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.
purpose
Natural selection has no goals. Natural selection is not progress.
creation
Natural selection explains species diversity and adaptations materialistically. Creation mechanisms need have no creator.
examples
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.
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}.
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.
Species members with best adaptations have highest percentage of survival to reproductive age {survival of the fittest, selection}|.
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.
Parents can care for relatives' children, or relatives {kinship group} can help each other {kin selection}.
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.
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.
In one ecosystem, competition can separate two similar species into separate niches {competition exclusion principle} {Gause's principle} {Gause principle}.
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Date Modified: 2022.0225