Sciences {biology} can include botany, cell biology, development, ecology, evolution, genetics, and zoology.



organism structures {anatomy}|.

natural history

nature {natural history, nature}|.


organism functions {physiology}|.


animal husbandry

farm animals {animal husbandry}| {husbandry}.


gardening {horticulture}|.


Food can grow in aerated nutrient-rich water {hydroponics}|, with no soil.


wine {viticulture}|.



organism development {embryology}|.


insects {entomology}|.


Animals have natural behaviors {ethology}|, such as aggression, imprinting, instincts, innate releasing mechanisms, and fixed action patterns, which evolve, develop, and have purposes. Environmental stimuli trigger innate complex behaviors. Perhaps, humans have innate behaviors or behavioral tendencies, such as aggression.


fish {ichthyology}|.


birds {ornithology}|.


palm reading {palmistry}|.


skull regions {phrenology}|.


stuffing animal skins and mounting heads {taxidermy}|.

4-Biology-Subjects-Cell Biology


cells {cytology}|.


enzymes {enzymology}|.


morphology in biology

structures {morphology, biology}|.


ancient times {paleontology}|.


People study excrement {scatology}|. People study obscenities.


classification {taxonomy}|.



sedation {anesthesiology}|.


bacteria {bacteriology}|.


heart {cardiology}|.


spine manipulation {chiropractic}|.


skin {dermatology}|.


hormones {endocrinology}|.


infectious diseases {epidemiology}|.


disease causes {etiology, disease causes}|.


old age {geriatrics}|.


old age {gerontology}|.


women {gynecology}|.


tissues {histology}|.


immune system {immunology}|.

internal medicine

general disease {internal medicine}|.


nervous system {neurology}|.


pregnancy {obstetrics}|.


cancer {oncology}|.


eye medical problems {ophthalmology}|.


eyesight {optometry}|.


bones and muscles {orthopedics}|.


bones {osteopathy}|.


ear and throat {otolaryngology}|.


Organisms can live on other organisms {parasitology}|.


disease {pathology}|.


children {pediatrics}|.


drug development {pharmaceutics}|.


drug information {pharmacology}|.

physical therapy

rehabilitation {physical therapy}|.

plastic surgery

Surgeons can reshape {plastic surgery}| nose, breasts, ears, eye sockets, and penis.


feet {podiatry}|.


colon {proctology}|.


mind diseases {psychiatry}|.


irradiation {radiology}|.


blood {serology}|.


development diseases {tetralogy}|.


therapy {therapeutics}|.


poisons {toxicology}|.


urinary tract {urology}|.


viruses {virology}|.



teeth alignment {orthodontics}|.


gums {periodontics}|.


mouth and teeth devices {prosthodontics}|.



fungi {mycology}|.


algae {phycology}| {algology}.


plants {phytology}|.


life in biology

Self-contained, integrated structures {life}| have mechanisms for gathering and using energy and matter, to build mechanisms and reproduce similar structures. Living organism species come from one or two genetically similar organisms. Species communities live in local regions. Community ecosystems live in large geographic regions or climate zones. Living things adapt, grow, have irritability, and reproduce. Living things have sizes, shapes, biochemical reactions, molecules, and movements.


Biochemical molecules, organelle molecular structures, cell molecular systems, tissue cell types, and organ-system tissue groups can work as units {organism}| {individual}. Organisms eat each other, live in different environments, and use oxygen differently.


Killing can be for the sake of mercy {euthanasia}|, either by letting people die or by painless killing.

irritability of organism

Organisms can react to stimuli {irritability, organism}|.

life force

Perhaps, living things need special energy {life force} for motion and organization. However, molecules and physical laws can make life. Organic molecules, cells, organisms, species, and all life can be purely physical and require no extra information or non-physical energy.

spontaneous generation

Perhaps, living things can arise directly from molecules or decaying matter {spontaneous generation}|. However, organisms are too complex to arise directly from molecules or decaying matter. Organisms arise only from other living things, which contain information needed to initiate and develop life through complex processes. At life's origin, more-complex molecules, between living and non-living, arose from complex molecules by moderately complex processes.

4-Biology-Life-Body Locations

cephalic side

head {cephalic}.

cranial side

about head {cranial}.

humoral body fluids

about body fluids {humoral}.

medial side

middle {medial}|.

4-Biology-Life-Body Locations-Front And Back

dorsal side

back {dorsal}.

ventral side

abdominal, anterior, or lower {ventral}|.

4-Biology-Life-Body Locations-Head And Tail

caudal side

tail {caudal}.

rostral side

head {rostral}|.

4-Biology-Life-Body Locations-Lateral

lateral side

side {lateral, side}|.

contralateral side

opposite side {contralateral}|.

ipsilateral side

same side {ipsilateral}|.


origin of life

Experiments simulating primitive Earth conditions can make small organic molecules. Under special conditions, these molecules can make large stable proteins, ribonucleic acids (RNA), and deoxyribonucleic acids (DNA) {origin of life}|. DNA has optimum mutation rate, crossing-over, hybridization, and long length and so can be replication templates.

early-Earth molecules

Experiments replicating early-Earth conditions make formaldehyde, formic acid, lactic acid, acetic acid, urea, sugars, and hydrogen cyanide. From nitrogen, methane, ammonia, water, and hydrogen-gas mixtures, lightning or ultraviolet light can produce amino acids. Metallic carbides and water can react to form acetylene. Formaldehyde can polymerize to make ribose and other sugars.


Living things replicate, so life requires replicating molecules. Proteins cannot be templates, because most amino acids can have no hydrogen bonding. RNAs are easy to create. However, RNA is also easy to hydrolyze, so only short RNA regions can replicate. DNA does not hydrolyze, because deoxyribonucleotides have no oxygen atom and prevent hydrolysis. DNAs are harder to create but can be templates.

cell functions

After DNA formation, DNA regions able to make functional RNAs and proteins arose. To these exons, evolution added and subtracted introns. Archaebacteria have tRNA and rRNA introns. Cyanobacteria eubacteria have leucine-tRNA introns. Eukaryote RNAs typically have introns. Eukaryote DNA has different intron types, such as self-splicing introns. Currently, gene exons have 1000 to 7000 functional DNA regions.

cell functions: photosynthesis

Earth life needs photosynthesis, using metals, enzymes, carbon dioxide, and water.


Perhaps, chirality is necessary.

sexual reproduction

Earth life needs sexual reproduction, for more variation and more competition. Sexual reproduction began 2.2 x 10^9 years ago. Sexual intercourse began 2 x 10^8 years ago.


Different DNA types change at different rates. Mitochondrial DNA mutates ten times faster than nuclear DNA. Mitochondrial DNA mostly comes from mother, but some paternal genes can enter and recombine. DNA-change rates can be faster if codon changes do not change amino acids produced. DNA-change rate is slower for histones and other fundamental proteins. DNA-change rate is slower in humans than in other species.

gene duplication

With sexual reproduction, genes can duplicate by unequal crossing over at recombination. If genes duplicate, one copy can change while the other still provides original functions, thus allowing genetic drift.


DNA amount and gene number can increase for whole genome, tRNA, rRNA, mitochondrial DNA, and globin DNA, increasing organism complexity.

Drake equation

Percentage of planets that can have intelligent life depends on star formation rate, fraction of stars that have planets, percentage of planets that are suitable for life, fraction where life actually exists, intelligent-life probability, and average civilization longevity {Drake equation} (Frank Drake) [1961]. For planets to have life, they must be like Earth and have stars like Sun.


Sun is a yellow-orange class-G0 star. Only class F, G, and K stars can have suitable planets, because liquid-water zone is too small for smaller stars, and bigger stars have no rocky planets in that zone. Such stars have masses 0.7 to 1.5 times Sun mass. Lifetimes are long enough, and masses are big enough, for planets. Stars sufficiently like Sun are 1% of all stars.

Stars younger than Sun have time too short for life. Stars older have too few heavy elements. Time range is 3 to 7 billion years, one-third of all stars.

Multiple stars can have no planets. Single stars are one-fifth of all stars.

Stars with slow spins possibly indicate planets. Probably, one sixth of all stars qualify.

Stars must be in galactic arms. Galaxy centers have too much radiation. Edges have low metals and low star-formation rates. Galactic habitable zone is far from center and edge.


Circular orbits make temperature swings not too great. Probably 100% of planets at correct distance from star have circular orbits.


Earth size is big enough to retain oxygen and nitrogen and small enough to lose hydrogen and helium, so as not to have too much gas. Surface gravity is not too strong or too weak for living things. Diameter is 5000 km to 15000 km. Probably, one tenth of all planets have correct size. Therefore, 0.001% of all stars have Earth-like planets. Galaxy has 2.5 x 10^11 stars and so 2.5 x 10^6 habitable planets.


Planet rotation must not be too fast or slow. Probably 100% of planets at correct distance from star have Earth-like rotation speeds.


On early Earth, volcanoes gave off steam, nitrogen, methane, hydrogen cyanide, ammonia, carbon dioxide, and sulfur dioxide or hydrogen sulfide. If iron was already at core, atmosphere was carbon dioxide, nitrogen, and sulfur dioxide. Soon after Earth formed, atmosphere layered into decreasing-density gases. Ultraviolet light reaching Earth decreased, and temperature lowered. Crust cooled quickly, and lower temperature led to more atmosphere layering. Hydrogen, ammonia, and methane were no longer in oceans, so processes no longer formed organic molecules. Temperature became too low to make organic molecules. All gases can dissolve in oceans.


If planet surface temperature is hotter than 40 C, proteins denature and water evaporation is too high. If surface temperature is colder than ice, no water is available. Planets must be in circumstellar habitable zones. If planet forms too close to star, it has little water and large greenhouse effect, like Venus. If planet forms too far from star, surface is ice. Distance from star is 10^7 km for optimum temperature. Probably, one tenth of planetary systems have such planets. Composition, size, wind, rain, and sunlight cause tectonic and erosion processes.


If planet is at correct distance from star, mineral composition is similar to Earth mineral composition.


Cosmic radiation can react water and carbon dioxide to make organic acids.


3,800,000,000 years ago, ultraviolet light, lightning, meteor impacts, thunder, volcanic heat, and hydrothermal vents provided energy.

meteors and comets

Perhaps, some organic molecules came to Earth in meteors and comets. Meteors have saturated hydrocarbons, porphyrin rings, and organic acids. Spores cannot come from space, because ultraviolet and ionizing radiation kill them.


First life probably arose in shallow seas or tidal areas. Oceans probably had water, gases, proteins, nucleic acids, carbohydrates, fats, and adenosine phosphate.


Shallow seas with high evaporation rates allow molecule concentration. Tides add water. Large moons can cause tides. On Earth, tides were 30-meters high when Moon formed.

other factors

Probably, Earth life needs continental drift, orbital changes, star evolution, seasons, days and nights, major climactic changes, and magnetic fields.


Earth life needs no life-ending catastrophes, like too many comets or meteors, too much volcanism and earthquakes, too much erosion, or too much greenhouse effect.

life factors

Earth life needs brains, hands, vocal chords, speech centers, forebrains, vision, immune systems, and societies. Earth life must be large enough, be long-lived enough, be few in number, have slow reproduction cycles, and have long childhoods. Earth life must have no mass destruction, optimum competition, optimum population, enough energy and resources, few radioactive wastes, few chemical wastes, optimum ozone, and social cohesion.

number of times

On Earth-like planets, life has probability, possibly 10^-6. Perhaps, galaxies have 10^6 suitable planets. Therefore, galaxies have one planet with life. If other planets have intelligent life, they can send probes to Earth, but there is no evidence for this. Therefore, no other intelligent life forms are in Milky Way Galaxy yet.

first cells

Life began as non-photosynthetic one-celled bacteria-like organisms. First cells reproduced themselves, protected themselves, and found energy.


All cells have cell membranes. Cell membranes have lipids with embedded proteins. Cells can control membrane-molecule amounts and ratios. All cells have voltage differences across cell membranes, because inner and outer sodium, potassium, and chloride salt concentrations differ.

energy and entropy

Life can overcome dissipative forces and persist. Living systems have high order {negentropy} in small regions, surrounded by large energy sources that they can tap. Living systems must gather energy faster than surroundings can dissipate energy. Sunlight energy, planet interior heat, and lightning can make locally high temperature, for anabolic and catabolic chemical reactions.

Small cells have small fast energy changes. Fast heat and material exchanges among physical compartments allow rapidly removing order from surroundings. High combination and division rates make many new organic molecules and cells. Equilibrium conditions in oceans or tide pools allow reversible chemical reactions.

Fermi paradox

If life is abundant in universe, why have people not seen other intelligent life {Fermi paradox}?


circumstellar habitable zone

Planets must have liquid water, not ice or steam {circumstellar habitable zone} (CHZ).

galactic habitable zone

Galaxy centers have too much radiation. Galaxy edges have low metals and low star-formation rates. Stars must be in galactic arms {galactic habitable zone} (GHZ).

hydrothermal vent

Hot water rich in sulfur, iron, hydrogen, and carbon flows from sea floor holes {hydrothermal vent}|. Bacteria-like organisms began there.

reducing atmosphere

If surface had iron 3,800,000,000 years ago, reduction reactions caused methane, ammonia, and hydrogen sulfide {reducing atmosphere}.


carbon-based life

Carbon compounds {carbon-based life} can be soluble or insoluble and have intermediate-stability chemical bonds, so they can form and break at moderate energies.

organic molecules

Organic molecules formed in seas. Stable forms persisted. Persisting molecules aggregated.

nucleic acids

When nucleotide concentrations were great enough, nucleotides linked. Nucleic acids used themselves as templates to make copies. Good copiers persisted and used more nucleotides. Mutations resulted in populations with property ranges.


When amino-acid concentrations were great enough, amino acids linked. Peptides assisted chemical reactions and formed structures.


Later, photosynthesis added oxygen to atmosphere, using water, sunlight, and atmosphere carbon dioxide.

silicon-based life

Silicon compounds {silicon-based life} cannot substitute for carbon compounds, because silicon compounds are insoluble, silicon makes shorter bonds, and silicates are too stable.

chirality in molecules

In living organisms, sugars and amino acids are in only one of two possible stereochemical forms {chirality, molecule}|. Sugar and amino-acid chirality probably had survival value, but people do not yet know cause [Gardner, 1960].


Perhaps, living things or organic molecules are in cosmic dust, meteors, comets, asteroids, and planets and then travel to Earth in dust, meteors, or comets {panspermia}.



Glycerin molecules mixed with other molecules can clump together to make stable gels {coascervate}| [1926]. Other molecules can enter, interact inside, and leave.


Nucleic acid and protein can combine. Perhaps, dissolved genes in early oceans evolved to make genes with protein shells {proto-virus}. Proto-viruses can acquire lipid layers, making micelles. Proteins can embed in lipids, to make cell membranes. Food can pass from seawater into simple cells. Chemosynthesis can evolve. Simple cells can replicate. Later, photosynthesis can evolve.

RNA world

Perhaps, RNAs had genetic codes, were enzymes, and formed structures {RNA world}. RNAs folded and unfolded to perform functions.


endosymbiosis theory

Eukaryote-cell organelles can come from eubacteria incorporated into cells {endosymbiosis theory}. Plant chloroplasts came from cyanobacteria. Animal mitochondria came from purple photosynthetic bacteria. For example, Cryptomonas phytoflagellate combines eukaryotic nucleus, photosynthetic prokaryote, and eukaryotic cell.

exon shuffling

Evolution has added introns to, and subtracted introns from, DNA, possibly to aid exon recombination {exon shuffling} and combine protein functions.


Bacteria have one circular chromosome {monoploid}|. Polyploid protozoa have several linear-chromosome copies. Perhaps, bacteria are simplified polyploid protozoa.


evolution in biology

New species develop from existing species {species evolution} {evolution, species}|.


On early Earth, heat, light, lightning, and meteor collisions formed carbon-containing molecules {organic molecule, life} with attached hydrogen, oxygen, nitrogen, sulfur, and phosphorus atoms. Simple organic molecules combined to make sugars, amino acids, nucleotides, and fatty acids, which combined to make carbohydrates, proteins, nucleic acids, and lipids. Large molecules can have shapes and structures and can have multiple binding and reaction sites. Structural molecules combined to form cells, viruses, and bacteriophages.


The first cells were the first species. Cells evolved into single-cell Archaea. Archaea evolved into bacteria and single-cell plants and animals. Single-cell organisms evolved into multicellular plants and animals. Multicellular animals evolved into invertebrates. One invertebrate species evolved into vertebrates. One vertebrate species evolved into fish. One fish species evolved into amphibians. One amphibian species evolved into reptiles. One reptile species evolved into mammals. One mammal species evolved into primates. One primate species evolved into monkeys. One monkey species evolved into apes. One ape species evolved into anthropoid apes (great apes) (hominids). One hominid species evolved into hominins (human ancestors) and Homo sapiens.


Prokaryotes have no nucleus. Eukaryotes have nuclei. Multicellular eukaryotes have neurons, sense cells, and muscle cells. Invertebrates can have bilateral symmetry, as in flatworms. Prechordates have notochord beginnings. Chordates have notochord in one development stage. Vertebrates have vertebrae. First fish have cartilage. Bony fish have bones. Lobe-finned fish have fin stumps. Fresh-water lobe-finned fish live in fresh water. Amphibians live on land and in water. Reptiles can live only on land. Mammals make milk. Primates have forward eyes. Old World monkeys have tricolor vision. Hominids, hominins, Homo, Homo habilis, Homo erectus, and Homo sapiens follow.


Evolution requires objects that carry coded information about how to build and maintain structures and functions and about how to replicate themselves. Evolution requires mechanisms to build objects, maintain objects, replicate objects faithfully, and provide slight variations in coded information. Evolution requires environment that has scarce resources. Evolution requires competition among similar objects. Objects then replicate more or better.


Evolution can affect whole Earth, biomes, ecosystems, clades, or demes. Evolution can act on kingdoms, phyla, classes, orders, families, genuses, species, and varieties. Evolution can act on organs, tissues, cell lines, chromosomes, genes, exons, DNA functional regions, and nucleotides. Different levels can have different selection laws.


If organisms change, other organisms change in response, and relations between other organisms and environment change. Change can cause exponential change. However, change is disruptive and decreases survival for most organisms.

Universal Darwinism

Systems that make copies, have variations, and have a selection mechanism can evolve {Universal Darwinism} [Dawkins, 1976] [Dawkins, 1986] [Dawkins, 1995].

intelligent design

Religionists can believe that God helped form some species. God used special structures and functions that distinguish humans from other species. However, intelligent design does not seem to allow human-appendix creation or maintenance. Complex life forms need to eat less complex forms. Intelligent design allows arbitrary changes and so has no testable hypotheses.


Perhaps, both intelligent design and evolution are incorrect. Really, physical laws determine all, with no higher principles. Evolution works only haphazardly, with most species dying out.


Natural selection can make more-complex higher-level organisms {macroevolution}.


Structural constraints allow special forms {orthogenesis}| and guide evolution. Evolution can proceed directly from primitive species to higher species, without side branches. Evolution can jump to new species, without gradual steps.

phylogenetic inertia

Food specializations, migrations, and dangerous predators increase ecological-or-environmental pressures and increase evolution. Available genes, gene variability, adaptable behaviors, and food types resist evolution {phylogenetic inertia}.


species in ecology

Interbreeding organisms {species, ecology}| are basic biological units. Similar organisms share gene sets. Related species share similar structures, functions, and genes.


New species can arise from existing species {speciation}|.


Hybrids between two different species sum chromosome-pair numbers. If eggs are fertile, self-fertilization starts new species intermediate between parent species. Chromosome doubling created many plant species and some animal species.

chromosome change

New species can arise through chromosome-number or gene-order change. Human chromosomes differ from chimpanzee chromosomes by inversions in nine chromosomes and by fusion of two chromosomes.

divergence principle

New species can appear if species diverge {principle of divergence} {divergence principle}. Typically, species gradually diverge into varieties, then subspecies, and then species. Behavior traits can diverge in ten generations. Major changes, such as brain development, diverge in 100 generations. New species diverge in 2000 generations. Species formation by divergence typically requires subspecies geographic isolation, to prevent gene dilution by other subspecies. Species diverge if organisms have different niches in same geographic area. Species converge if organisms live in separate areas with similar niches.


Species have original varieties {holotype}.


Organisms can perform similar functions using different structures {homoplasy}.

homology of organisms

Organisms can have similar internal structures {homogeny} {homology, organism}|. Homology can result from keeping fundamental internal structure during evolution {parallelism, evolution} or having same external pressures during evolution and evolving to similar structures {convergence, evolution}.

endosymbiont hypothesis

Early eukaryotes incorporated primitive bacteria {endosymbiont hypothesis}, which evolved to mitochondria and chloroplasts.


Larval stages can become sexually mature {heterochrony}, to make new species.


Larval stages can become sexually mature, to make new species {paedomorphosis}.


Adult stages can add features, to make new species {peramorphosis}.


classification in biology

Earth has 2,500,000 species in many categories {classification, biology}. Earliest life was one-celled organisms. Archaea included thermophiles. Bacteria included proteobacteria and later cyanobacteria blue-green algae. Eukaryota included metamonad, parabasalid, trypanosoma, ciliates, and flagellates. Multicellular organisms arose from eukaryotes.


Many-celled organisms {metazoa}| {multicellular organism} include fungi, plants, and animals. Metazoa have specialized tissues.


Only eukaryotes can be multicellular organisms. About 650 million years ago, protozoa clustered, and cells differentiated into different tissues. Later eukaryotes evolved neurons. Later, jellyfish evolved sodium-ion channels for action potentials, which allow neurons to communicate over any distance.

gene transfer

Early eukaryotes incorporated early alpha-proteobacteria to make mitochondria. Early eukaryotes incorporated early cyanobacteria to make chloroplasts. Perhaps, eukaryote cytoskeleton and internal membranes came from early spirochetes, flagellates, or ciliates.

binomial nomenclature

Organism names are genus name followed by species name {binomial system} {binomial nomenclature}|, such as Escherischia coli.

4-Biology-Evolution-Classification-Cell Nucleus


One-celled organisms {prokaryote}| {Monera} {Prokaryota} can have no distinct nucleus or other cell organelles. Prokaryotes include archaebacteria and eubacteria. Eubacteria include blue-green-algae cyanobacteria.


Cells {eukaryote}| (Eukaryota) (Eukarya) can have one cell nucleus surrounded by membrane. Eukaryotes include protozoa, fungi, plants, and animals. Eukaryotes are not Archaea, bacteria, blue-green algae, viruses, or bacteriophages.


kingdom of organisms

The largest organism groups {kingdom, classification}| include non-nucleated single-cell archaebacteria (Archaea), non-nucleated single-cell eubacteria (Bacteria), nucleated single-cell protozoa (Protista) {protist}, nucleated fungi (Fungi), nucleated multi-cell plants (Plantae), and nucleated multi-cell animals (Animalia).


Domains are Archaea, Bacteria, and Eukaryota. Archaea include thermophiles. Bacteria include proteobacteria, cyanobacteria, and other bacteria. Eukaryota include protozoa, yeast and other fungi, algae and other plants, and animals.


Bacteria include cyanobacteria blue-green algae. Other algae are plants.


Fungi include yeast.

division of organisms

Kingdoms have major organism types {phylum} {phyla} {division, classification}|.

class of organisms

Divisions/phyla have subdivisions {class, classification}|.

order of organisms

Classes have subclasses {order, classification}|.

family of organisms

Orders have suborders {family, classification}|.

genus of organisms

Families have subfamilies {genus, classification}|.

species of genus

Genuses have interbreeding subgenuses {species, classification}|.


variety of organisms

Species have subspecies {variety}|.


Humans have varieties {race, people}, such as north European white {Caucasian, people}, south European white {Mediterranean, people}, European and American Indian {mestizo}, Spanish-speaking or Portuguese-speaking country of South and Central America {Hispanic}, Central America {Latino}, Mexico {Chicano}, Africa {Negro} {black, person} {African-American}, and Asia {Asian} {Oriental, people} {Asian-American}.


People have three races, totaling 30 varieties.

Races {Caucasoid race} can include the varieties Mediterranean, Nordic, Alpine, Armenoid, and Dinaric. It can have more pale red, white, or light brown skin color, be taller, have longer or broader head, have light to dark hair, and have higher nosebridge. Armenoid has Caucasian and Mongoloid. Dinaric has Caucasian, Negroid, and Mongoloid.

Races {Negroid race} can include the varieties African, South Pacific, Melanesian, Oceania, White Hottentots, Bushmen, extinct Tasmanian, and Negritos or pygmies. It can have browner skin color, longer head, thicker lips, darker and coarser hair, darker eyes, lower nosebridge, and broader nostrils.

Races {Asiao-American Race} {Yellow Race} {Mongoloid race} can include the varieties Tungus in Siberia, Oriental, Eskimo, Indonesian, American Indian, Ainu in Japan, Australoid, and Veddoid, as well as Beijing Man, Lantian Man, and Jinniushan Man. Oriental has Chinese and Japanese. Oceanian has New Guinean, Australian, and Aborigine. Eskimos are more separate from Oriental than Oceanian. Mongoloid race started in Central and East Asia and went to South Asia and Southeast Asia. It can have more yellow or red skin color, be average height, have broader head, have less body hair, have darker eyes, have more epicanthic fold, have lower nosebridge, have higher eye sockets, have flat face bones, have higher superciliary arches, have more spade-shaped incisor insides, and have darker, straighter, and coarser hair.

Aborigines in Australia, Dravidians in south India, Polynesians in South Pacific Ocean, and Ainu in north Japan are hard to classify.


Gene differences show that original Homo sapiens split into proto-Africans-and-Europeans, proto-Oceania, proto-American Indians, and proto-Oriental peoples. Then African Negritos and Bushmen separated from European Germanic and Mediterranean, so Europeans were intermediate between proto-African and proto-Oriental peoples.

Alu-repeat and short-tandem-repeat polymorphisms divide people into sub-Saharan Africa, Europe and West Asia, East Asia, Polynesia, and Americas groups. Perhaps, sub-Saharan Africa had two groups, including Mbuti pygmies. Genetic variants are 90% same, so group differences are maximum 10%.

cold adaptations

In cold regions, people tend to have shorter limbs, larger bodies, thicker eyelids, flatter noses, flatter foreheads, and broader cheeks.


Decreased environmental pressures, increased mutation-causing agents, more socially-useful genes, greater specialization, and faster environment changes affect human evolution.

multiregional hypothesis

Y-chromosome studies indicate that modern human did not arise from multiple origins {multiregional hypothesis}.

out-of-Africa hypothesis

Y-chromosome studies indicate that modern human races arose from African population [-89000 to -35000] {out-of-Africa hypothesis}.



Organism-classification systems {cladistics}| can depend on evolutionary, gene, structural, and functional features.


Species can split into independently evolving lines {clade}|. Different clades have different speciation rates, which can change over time. Clades determine classes and hierarchies, shown in branching diagrams {cladogram}. Cladogram nodes represent shared homologies.


natural selection

Species members make species members similar to themselves. Among variations, surviving and reproducing member adaptations increase percentages {natural selection, evolution}|. Natural selection affects phenotypes, which relate to genotypes, which vary by mutation or allele recombination.


Natural selection has no goals. Natural selection is not progress.


Natural selection explains species diversity and adaptations materialistically. Creation mechanisms need have no creator.


Peppered moths become darker or lighter in industrial or rural areas, because birds eat lighter or darker moths in industrial or rural areas. Bacteria develop antibiotic resistance. Insects develop insecticide resistance. Rats develop rat-poison resistance. People still have sickle-cell anemia, because it helps fight malaria. People still have tuberculosis, because it has vitamin-D-receptor gene. People still have cystic-fibrosis CTFR gene, because it helps fight typhoid.

selection types

In unpredictable environments, organisms tend to have fast development, many offspring, and offspring with few defenses {r-selection} {r selection} {opportunistic selection}, so population can increase in favorable periods. Unpredictable environments have fewer species. In predictable environments, organisms tend to have slower development, few offspring, and offspring with defenses {k-selection} {K selection}, so population is stable. Predictable environments have more species {selection, evolution}.

social evolution

Societies evolve through time {social evolution}. Social evolution includes new defenses against predators, higher feeding efficiencies, higher reproductive efficiencies, lower child death rates, more population stability, and new territories and environmental changes. Social evolution is more in stable environments. Social evolution seldom happens in variable environments.

survival of the fittest

Species members with best adaptations have highest percentage of survival to reproductive age {survival of the fittest, selection}|.

extinction of species

Species die out {extinction, species}|. Extinction typically happens soon after species formation. Extinction can happen if environment capacity is not enough. Increased speciation increases species extinction. Better adaptation prevents extinction. Slow variation and slow environmental change prevent extinction.

kin selection

Parents can care for relatives' children, or relatives {kinship group} can help each other {kin selection}.


competition in species

Species members compete for food, mates, and territory {competition, evolution}. Different species compete as predators and prey. Territory competition can cause convergence in dominant species and divergence in dominated species. Species typically relinquish habitat to competitors to keep preferred food, rather than staying and eating new foods.


Animals {predator} can eat other animals {predation, competition}|. Predators kill young, weak, and sick population members.

aggression in evolution

Aggressive behavior {aggression, ecology} protects territory, establishes dominance, protects sexual property, gets sex partners, disciplines, weans, imposes morals, predates, prevents predation, causes fear, expresses anger, and irritates. Most aggressions happen in competitions between species members. Examples are sexual aggression and food, territory, and status competition. Aggressive behavior patterns and levels evolve to adapt to environments. Species members vary in aggression levels.

Gause principle

In one ecosystem, competition can separate two similar species into separate niches {competition exclusion principle} {Gause's principle} {Gause principle}.


variation in species

Species members have different gene-allele combinations and so have different trait combinations {variation, species}|.


Mutations or allele recombinations cause genetic variation. Sex increases variation by increasing gene combination.

causes: selection

Evolution typically changes population allele ratios. Climate changes increase variation by increasing environment variety. Isolation increases variation by increasing environment variety.


On average, 6% of vertebrate genes vary from wild type. On average, 15% of plant and invertebrate genes vary from wild type.


Most changes are not adaptive. Species with greater genetic variation evolve faster, because they can use more environmental niches.

effects: duplication

Gene duplication and body part duplication allow duplicates to perform new functions, while originals perform old functions.

effects: whole body

Isolated changes can happen, but, to be adaptive, changes must work together with whole body, which then evolves in response to changes. For example, brain and body evolved together. Finger muscles, bone, nerves, blood supply, and brain motor-and-sensory finger regions evolved together, because dexterity required linked development.


Populations have gene-frequency changes {microevolution}. Microevolution includes gene flow, mutation pressure, and segregation distortion.

natural selection

Natural selection causes most gene-frequency changes. Natural selection can cause adaptations in constant environments or make new genes in fluctuating environments. Natural selection typically stabilizes gene frequencies and decreases homozygote percentage. New species arise from microevolutionary changes by accumulated changes in one direction {progressive evolution}.


Random gene-splicing errors can cause heterozygosity loss by genetic drift, but this factor only affects small populations with inbreeding and consanguinity.


Allele mutations can negatively affect other alleles {canalizing}.

gene flow

Immigrations into populations {gene flow} have major and fast gene-frequency effects, mainly through hybridization.

hybrid strain

Strain combinations {hybrid}| generally show the good results of outbreeding {hybrid vigor}.

Mongolian spot

Bluish pigmented areas {Mongolian spot} {Mongol spot} {blue spot}, near spine bases, are present at birth in some Asian, south European, American Indian, and black infants and typically disappears during childhood.

mutation pressure

Minor gene-frequency-change factors {mutation pressure} include differing allele-mutation rates.

segregation distortion

Minor gene-frequency-change factors {segregation distortion} {meiotic drive} include unequal allele production by heterozygous parents.

sexual dimorphism

Males typically have larger size and different shape than females {sexual dimorphism}|.

proximate factor

Trait presence depends on making trait {proximate factor} and keeping trait during reproduction. Trait survival in species members depends on environment, reproduction accuracy, and protection from change {ultimate factor}.


adaptation of organism

In environments, organisms can adjust behavior {adaptation, organism}| to survive and reproduce.


To reproduce, species members must survive to sexual maturity. They must get food, avoid predators, fight disease, and maintain temperature, in a struggle for survival.


To optimize environment use, species can use different foods, decrease development time, increase temperature range, increase air or water pressure range, use protective coloration, use warning coloration, use mimicry, and use other species.


Genes alleles vary proportions and interactions. Alleles remain available to survive slow, catastrophic, or cyclic environmental changes and to use different environment niches.

adaptive radiation

Species evolve to new varieties that can occupy surrounding environments {adaptive radiation} {radiation, adaptive}.


As structures shift, functions and adaptations can be different {functional shift} {cooptation}. Small structure shifts are not necessarily adaptive.

Cope rule

Organisms tend to evolve to larger size {Cope's rule} {Cope rule}. Larger organisms typically compete better for sex and food and have better protection from predators. Evolution tends to build larger and more complex organisms.


Animal tops and bottoms can have different colors {countershading}|. For example, bottoms can be light to match sky, and tops dark to match sea.


Organisms can alter their surroundings {environment} [Bateson, 1916] [Cosmides et al., 1992].

grade in development

Species can pass through trait-development stages {grade, development}.

homeostasis in animals

Negative feedback keeps involuntary muscle actions and chemical levels within normal ranges {homeostasis, animal}.


Longer lives {longevity}| are adaptive in stable environments, harsh and unpredictable environments, low progeny-survival-rate conditions, and low-fertility conditions.


Species can imitate other species {mimicry}|.


Organism features {preadaptation} can find new uses in new environments.

protective coloration

Species can change color for disguise {protective coloration}|.

warning coloration

Species can change skin or coat color and pattern to scare predators {warning coloration}|.


convergent evolution

Evolution can make similar structures and functions in different species {convergent evolution}, to adapt to similar environments.

divergent evolution

Evolution can make new species varieties, then subspecies, and then new species {divergent evolution}, to adapt to environment niches.


habitat tracking

Species try to stay in environment niches {habitat tracking}.


Different habitats cause differences among people {polygenesis}.



New species arise in geographic isolation {allopatry}.


New species do not arise in same location {sympatry}.



Reproductive fitness {fitness} is adaptations that maximize offspring that live to make offspring. Fitness maximizes number of genes passed to offspring, which pass those genes to offspring.

differential fitness

Replicate number and adaptability depend on how well environment and species members interact {differential fitness}.


Gene alleles can affect other-allele fitness {epistasis} {epistasy} {epistatic coupling}. Gene mutation can affect mutation expression at other loci.

evolutionary stable strategy

Ecosystems can maintain stable alleles in stable species {evolutionary stable strategy}. Evolutionary stable strategies apply game-theory Nash equilibria to ecosystems. If allele change reduces other-species fitness, it reduces species fitness.


reproduction in evolution

One or two organisms can make new organisms {reproduction, organism}|, by sexual or asexual reproduction. Reptiles determine sex by egg temperature, not by Y-chromosome. Birds and mammals determine sex by chromosome. More sexual selection, higher fecundity, and higher rates of survival to reproducing age {differential reproduction} improve survival.

reproductive effort

Reproductive processes take time and energy {reproductive effort} away from predation and protection and escape from predation. Reproductive effort is more if reproductive rate is more. Higher non-social animals have low reproductive effort, but higher social animals have high reproductive effort. Societies perform predation and food gathering most, anti-predation next, and reproduction least. Function time varies with food shortage, danger, or mating season.

reproductive rate

Net population growth rate {reproductive rate} depends on death rate and birth rate. Young, weak, and sick population members have low reproduction. Older population members have high reproduction, producing more offspring and guarding them better. Stronger and more active population members have high reproduction, especially if they start new colonies and occupy new habitats. Species have optimum fertility rates, based on reproductive rates.


Natural objects {replicator} can copy themselves {replication, nature}, using available resources.


Replicators and replicates are alike. If replicate survives, it is like replicator survives.


Replication requires reproduction mechanisms to assemble parts. Replication requires template patterns to copy.


Organisms use resources for replication, eating, and escaping, so they must balance these activities. Survival to reproductive age requires eating and escaping.


Replicators are purposive, because they replicate. They are selfish, because they use resources to replicate. They are problem solving, because they gather and use resources to replicate. They are decision making, because they decide when and whether to replicate.


Species members must reproduce more organisms than environment can support {superfecundity, reproduction}. Superfecundity forces species members to compete against each other for mates and food, as well as other resources needed to reproduce. Species members must survive until sexual maturity, with strength to reproduce and win competitions for mates.

sexual maturity

Species members must reach reproductive age and development to reproduce {sexual maturity}. Before that stage, species members cannot reproduce {sexual immaturity}.

parental investment

Parents use energy and time {parental investment} to bring offspring to reproductive age. Children survive better if parents protect, feed, and teach them longer. However, parents can transmit more genes if they have more children, so parental investment is in equilibrium with children number.


Stable predictable environment, longevity, regular reproduction, large size, territoriality, few offspring, difficult environments, many predators, and food specialization favor more and longer parental investment.


Child raising by parents and relatives is altruistic kin selection. In many societies, non-relatives raise offspring, to gain child-raising experience and to limit aggression.


Societies typically have high societal investment in offspring. Insect societies have no parental investment, because adults do not directly affect offspring behavior.



Two opposite-sex animals can produce {mating}| offspring by uniting sperm and egg. Sexual reproduction allows more variation and more sexual selection.


Animals can have more than one mate. Polygamy is typical, because parental investment in children is typically unequal. Abundant food at least once a year, heavy predation, precocious young, greater longevity, different gender maturation ages, and different gender niches favor polygamy. High competition for mates leads to polygamy and mate monopolization. Polygamous species tend to have high sexual dimorphism.


Animals can have one mate. Monogamy is rare. Monogamy happens in territories with scarce resources that require two animals to maintain or defend. Monogamy happens in difficult environments. Monogamy happens in species with early breeding. Monogamous species tend to have low sexual dimorphism.


Mating {breeding}| related individuals {inbreeding, alleles} tends to pair recessive alleles. Mating unrelated individuals {outbreeding} mixes alleles more.

selective breeding

Species can choose mates for good survival characteristics {selective breeding}|. High competition for mates leads to polygamy and mate monopolization.

sexual selection

Organisms select mates {sexual selection}|. Sexual behaviors tend to resist social evolution.


Sexual behaviors can be strategies to ensure that parent has conceived cared-for offspring. For males, sexual selection can involve keeping other males away from females, to prevent reproduction. Males can transmit more genes if they produce more females, rather than males.

males: displays

In many species, male pattern and behavioral displays lure females. Displays are fewer if food is scarcer or predators are more numerous.


For females, sexual selection involves selecting mates. Species with more receptive females have less fighting among males. Females can transmit more genes if they produce one male.


asexual reproduction

One organism can make copies {asexual reproduction}| by budding, cell fission, regeneration, sporulation, or parthenogenesis.

budding reproduction

Asexual reproduction can have growth of special cells {budding}|, as in plants, hydra, and yeast.

fission of cells

Asexual reproduction can split cells {fission, cell}|, as in most cells.

regeneration reproduction

Asexual reproduction can have differential growth in broken-off pieces {regeneration, reproduction}, as in flatworms and starfish.


Asexual reproduction can uses special haploid or diploid cells {spore} that detach from organisms {sporulation}|, as in most plants and some animals.


Reproduction can be haploid egg developing into adult {parthenogenesis}|, as in honeybee, wasp, and other arthropods.


sexual reproduction

Two organisms can make organisms similar to themselves by uniting their DNA {sexual reproduction}|, using conjugation, copulation, or hermaphroditism.

fertilization in reproduction

In hermaphroditism and copulation, haploid sperm enter haploid eggs {fertilization, reproduction} to form diploid cells. Fertilization can happen in oceans, rivers, or lakes {external fertilization} or inside bodies {internal fertilization}.


Sex organs {gonad}| produce sperm or eggs.


conjugation for reproduction

Sexual reproduction can use DNA-region exchange, after temporary union of two one-celled organisms {conjugation, reproduction}, as in bacteria.


Sexual reproduction can use mutual egg fertilization by sperm from two individuals that have both sex organs {hermaphroditism}|, as in oysters, tapeworms, and earthworms.


evolution theory

New species develop from existing species {evolution theory} {organic evolution} {theory of organic evolution} {theory of evolution}.


Species members can make one or more organisms similar to themselves. Species members must reach sexual maturity to reproduce. Species members vary in fecundity.


Species members reproduce more organisms than environment can support {superfecundity, evolution}, so species members compete against each other for mates and food. In environments, species members must get food, avoid predators, fight disease, and maintain temperature {struggle for survival} to reach sexual maturity, have health and strength to reproduce, and win competitions for mates.


Species members have traits that affect the struggle for survival.


Species members differ over species-characteristic ranges. Parents and reproduced organisms typically have similar values. Mutation, crossing over, and development can change values, add new values, or add or subtract characteristics. Characteristics and values can affect adaptation, competition, and fecundity by altering strength, size, or skill. See Figure 1. Species members with best-adapted characteristics and values have highest percentage of survival to reproductive age {survival of the fittest, evolution}.


Environments have food sources, predators, diseases, climates, and cycles. Environments constrain species-member reproduction. Environments do not have enough food for all species members to stay alive, or be healthy and strong enough, to reproduce at reproductive age. Predators and diseases eat, kill, or harm species members, so they cannot reproduce at reproductive age. Environments have temperature cycles. Environments affect reproductive methods, such as how mates get together. See Figure 1.

natural selection

Species members compete for resources to reach reproductive age and reproduce. Species members vary in characteristics, so some species members have higher probability to win competitions and reproduce. Species members typically make members similar to themselves, so their characteristics increase percentages {natural selection, evolution theory}. Evolution shifts allele frequencies. See Figure 1. Evolution can also cause new genes.


Natural selection makes higher percentage of better-adapted species members, so species are better able to avoid extinction. Natural selection typically makes more surviving species members than before. Competition for food and mates becomes greater, causing higher pressure for survival. Over time, new species varieties arise. Over time, species varieties differ enough to be new species. For sexually reproducing species, new species members cannot reproduce with old species members. New species typically arise in isolated environments different from previous environments. New species can arise by combining two closely related species to make hybrids.


Cells, body, and environment supply energy and needed chemicals to make DNA physical structures that can be stable, vary slightly, replicate accurately, copy more or less, and contain enough information. DNA has four different nucleotides chemically bonded in long or short sequences. DNA positions can have any nucleotide. Genes are templates for making DNA by replication, RNA by transcription, and protein by translation. Copying mechanisms have one error per million DNA units. Besides copying errors, DNA and RNA can suffer physical and chemical mutation damage that changes nucleotides or disrupts sequence {rearrangement}. In sexual reproduction, combining DNA from two sexes mixes sequence segments by crossing-over. These processes cause sequence changes. DNA reproduces, varies, and depends on environment and individual, so it faces competition, has adaptation, and goes through natural selection. Different species have different genes and alleles.

copying instructions

Copying instructions is more accurate than copying products, because products have more and different parts than instructions, and products typically have damage [Blackmore, 1999].

selection levels

Perhaps, natural selection applies to cell lines, organisms, demes, species, and clades, as well as genes. Selection levels can work synergistically, in opposition, or independently.


Evolution is not best or perfectly adapted but constrained by history, random effects, and physical laws [Feynman, 1965].

evolution theory: Summary 1

Objects that can reproduce same structures and functions with small changes, and that occupy environments in which they can die before reproduction, tend to evolve characteristics that fit environment. Objects retain only changes that make them survive better.

evolution theory: Summary 2

Organisms produce more offspring than survive to reproduce. Though people can think that God makes organisms that almost all survive to reproduce, except for natural accidents, or that match reproduction rate with death rate, all species actually produce extra offspring, as shown by Darwin. Offspring vary traits. It is easily observable fact that species members vary in observable traits. Observable traits have microscopic traits that vary. Offspring pass microscopic and so observable traits to offspring. It is easily observable fact that all organisms try to reproduce and that offspring typically resemble reproducers. Offspring with traits more favorable for survival to reproductive age produce more offspring with same traits.

evolution theory: Summary 3

Natural selection removes unfit and designs fit. Organisms vary in random ways. Variations typically are harmful but can be adaptive. Variations can accumulate over generations. Natural selection can make more-complex higher-level organisms.

evolution theory: Summary 4

Because organisms over-reproduce, nature has competing organisms and species, so new ones must replace or push aside existing ones {wedge, evolution}, leading to better adapted species. Typically, environment changes slowly compared to species changes.

evolution theory: Summary 5

In geographic areas, organism number increases geometrically through reproduction, but food and mating resources have limits. Species members and all organisms have struggle for existence. Individuals have various trait values. On average, process selects individuals with the most-fit trait values. Over time, natural selection causes organism gene-frequency changes [Darwin, 1859] [Darwin, 1871] [Judson, 1979] [Gould, 2002] [Huxley, 1884] [Ridley, 2003].

gene theory

Specialized germ plasm reproductive cells transmit protein-coding genes that underlie physiological traits {gene theory}. Body cells do not affect germ-plasm genes, so genes cannot directly inherit learned behaviors {acquired characteristic} [Dubos, 1968] [Keller, 2000].

generalized theory of evolution

Evolution has general requirements {generalized theory of evolution}.


Evolution requires objects with properties, such as size or color, with different values. Evolution requires mechanisms to switch among property values and/or mechanisms that can make new values or new properties.


Evolution requires objects to have mechanisms that produce new objects with similar property values. Reproductive mechanisms typically use templates that carry coded information about object properties. Reproductive mechanisms do not copy perfectly but allow unit changes, such as mutations.


Objects and reproductive mechanisms require resources. Object reproductions produce more objects than environment resources can support.


Systems can have only one object type or can have multiple objects, object groups, and/or hierarchies.


Random events from inside or outside objects can affect objects, to cause new properties and values or affect reproduction.


Selective systems with variations among reproducing individuals who can pass on traits always evolve.

punctuated equilibrium

In small populations, new species can arise quickly under new environmental conditions {punctuated equilibrium} {quantum speciation}. Nature has many small populations. Fossils show many rapid species-evolution examples.



Lamarck said that organism actions cause body changes {Lamarckianism}. For example, giraffes have long necks through continual neck stretching. This theory is false in general, but organism actions can affect evolution in small ways by affecting mutation, crossing-over, and translocation.


Perhaps, neurohormones and neurotransmitters sent from brain can affect germ cells by changing gene expression or causing structural changes. Thus, learned behaviors can trigger chemicals that can alter germ cells. Alterations can correspond to learned behavior.


Perhaps, fittest individuals can sustain useless or harmful innovations that weaker individuals cannot have. Innovations can then evolve into useful traits, and species can evolve.


Perhaps, fittest individuals have more energy, matter, and organization to implement innovations that have no chance in weaker individuals. Innovations can then evolve into useful traits, and species can evolve.


Perhaps, all traits are adaptive {panadaptationism}. This theory is not true, because most traits are side effects and some traits are not good adaptations [Gould and Lewontin, 1979].


animal model

Animal diseases can model human diseases {animal model} {model, animal}. Germ-free animals are useful.


Disease progress and outcome depend on species, strain, genotype modifications, gender, and age. Disease agents and treatments have different locations and administration methods.


Animals contract other diseases regularly in laboratory settings, so animals must have no bacteria, such as Helicobacter and Camphlylobacter, or worms, such as Helminthes. Outside organisms can elicit immunologic, inflammatory, and cancerous effects to obviate experiment.

association study

Studies {association study} can compare allele frequency in disease and control populations. Frequency difference indicates that allele relates to disease. Genetic-linkage algorithms compare disease and control allele frequencies to find marker locus. Studies can compare allele frequencies among phenotypes.

carbon dating

Carbon-isotope ratios can date objects up to 100,000 years old {carbon dating}|.


Mass spectroscopy can measure isotope amounts in very small samples.


Lower-atmosphere carbon dioxide has radioactive carbon-14 {radiocarbon} to non-radioactive carbon-12 ratio. Living things have same carbon-isotope ratio as lower atmosphere.


Lower-atmosphere carbon-isotope ratio varies over time. Measuring air trapped in glaciers at different depths shows ratios at past times. Carbon-isotope ratio decreases after organisms die, because carbon-14 decays to nitrogen-14. Comparing current reduced ratio to atmosphere ratio at death indicates time of death.


Carbon dating is only useful up to 100,000 years ago, because almost all carbon-14 decays in 100,000 years.


Older carbon-dating methods needed more mass and used fire ashes or other organic materials adjacent to formerly living things, not living things themselves. Older carbon-dating methods assumed that atmospheric carbon-isotope ratio is constant. Because ratios actually changed, carbon-dating dates in scientific literature before 1990 are typically too recent. For example, earlier-reported -9000 is actually -11000 or 13,000 years ago.


Actual lower-atmosphere carbon-isotope ratios, measured at different glacier depths, can find correct dates {calibrated carbon dating}.


Techniques {dissection}| can open plants and animals to observe parts.

gene insertion

Shooting gold or tungsten particles carrying genes into cereal seeds {gene insertion} can cause gene insertion into cereal DNA.

leaf disk technique

Agrobacterium tumefaciens can attach to plant leaves and then transfer DNA, including foreign genes, into leaves {leaf disk technique}.

limb movement

Placing lights on joints and limbs allows filming limb movements {limb movement}.

monoclonal antibody

Injecting antigens into mice or rats causes immune responses and makes antibodies {monoclonal antibody}| in spleen lymphocytes.

hybrid cells

In cell culture, lymphocytes can mix with myeloma cell lines to make hybrid cells {hybridoma}. Polyethylene glycol helps hybridization.


Screening can find hybrid cells with large antibody quantities.


Rituxan works against lymphoma.

Herceptin {trastuzumab} works against breast cancer. Epidermal-growth-factor receptors (EGFR) make dimerization signals, which tell cells to divide. Herceptin binds to HER2 cell-surface epidermal-growth-factor receptors and prevents dimerization signals. Dimercept binds to HER cell-surface-receptor dimerization sites. Lapatinib kinase inhibitor inhibits HER2 receptors.

Kinase inhibitors inhibit PI3K, AKT, and mTOR in cell-survival pathway.

Letrozole aromatase inhibitor inhibits estrogen synthesis. Tamoxifen aromatase inhibitor inhibits estrogen and progesterone synthesis.

Bevacimuzab inhibits tumor blood-vessel formation at VEGF receptors.

Monoclonal antibodies can inhibit IGF-1 receptors.


Llamas and camels make half their antibodies {nanobody} using only heavy chains, which supply variable segments.

optical coherence tomography

Coherent light sources can split into reflected beams and beams that enter tissue, and then beams can interfere {optical coherence tomography}.

surface plasmon resonance

Techniques {surface plasmon resonance} (SPR) can measure protein site-binding strength.


axon flow

Squeezing nerve fibers causes axoplasm to accumulate on both sides, showing that nerve-fiber axoplasm flows {axon flow} in both directions.

Nauta technique

Techniques {Nauta technique} can stain degenerating axons with silver. First, electrodes stimulate neurons with electric current, or fine pipettes stimulate neurons with chemicals. Then fine pipettes inject dye into cells. After axon cutting, dye blackens dying-axon branches.

positron emission tomography

Techniques {positron emission tomography} (PET) can use radioactive oxygen or carbon isotopes to measure cerebral blood flow or metabolic activity. Oxygen isotopes in glucose or neurotransmitters emit positrons as they decay. Patients receive radioactive tracers by injection or in food. Scanners localize radioactivity to within several millimeters and within one minute. Localized radioactivity shows increased oxygen-metabolism and glucose-metabolism sites. Brain blood flow varies with metabolic activity, so PET indicates locations with increased blood flow.


Alternatively, patients can receive radioactive xenon by injection into blood. The most active neurons become the most radioactive.

carbon 14

Carbon(14) 2-deoxyglucose is similar to glucose. Neurons can absorb the radioactive compound but cannot metabolize it. Neurons that absorb the most radioactivity are the most metabolically active.

retrograde marking

Techniques {immunohistofluorescence} {retrograde marking} [1970] can stain neurons backward from injection site using horseradish peroxidase, colloidal gold wheat-germ agglutin, and fluorescent dyes.

single channel recording

Techniques {single channel recording} {patch clamping} can measure single-neuron electrical activity.

single photon emission computed tomography

Techniques {single photon emission computed tomography} (SPECT) can measure cerebral blood flow or metabolic activity, using light.

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Date Modified: 2015.0704

Description: 4-Biology