Evolution Flashcards
What did Charles Darwin do?
He wrote the Origin of the Species by Natural Selection; which explained how modern organisms evolved over long periods of time from common ancestors
how did meat eating birds evolve to not compete?
Evolved to have different characteristics for different niches
owls: crepuscular to nocturnal (dusk and dawn to night)
vultures: scavenged the kills
hawks: stayed diurnal (day)
Different animals with similar characteristics inhabit___
similar habitats around the world.
Evolution
the process of change over time
two causes of evolution
Natural selection and artificial selection
Natural selection
organisms that have the best characteristics to survive in an environment will live long enough to pass these superior alleles to the offspring and future generations
artificial selection
organism that have the traits that humans want are bred together to give the offspring the desired alleles to pass on to future generations
what did Hutton and Lyell discover that influenced Darwin’s theory?
The Earth must be millions of years old for the geological process to have time to shape it as we see it today
what did Malthus discover that influenced Darwin’s theory?
predicted that human overpopulation would experience war (for resources), famine, and disease. After deaths, the population size would be manageable again. (just like animals)
what did Lamarck discover that influenced Darwin’s theory?
proposed that organisms evolved by acquired traits. What happens to an individual will change its characteristics and this will be passed on to off spring (giraffe necks). this was WRONG trump voice
what did Wallace discover that influenced Darwin to publish his theory?
proposes evolution by natural selection. encouraged and recognized by Darwin.
The struggle for existence
members of a population must compete for limited resources (minerals, air, water, shelter). only a limited number can win.
What do the “winners” of the struggle for existence have?
had the best variations of a characteristic which made them superior in getting resources. they were the fittest
Fitness
how well an organism can survive and reproduce so the alleles for the survivor characteristic are passed on
in a population do all characteristics have a population?
yes. some of these variants are better suited to life in that environment. these will be passed on
adaptation
any heritable (passed on) characteristic that increases an organisms chance to survive and reproduce in a given environment (becomes most frequent allele, even if recessive)
survival of the fittest
the fact that the organisms with the adaptations Best suited for survival for life and reproduction will have the greatest rate of survival
when will natural selection happen
whenever more organisms are born then can survive. the less suited to obtain resources will die
Principle of common descent
suggests that all species come from common ancestors that evolved over time through natural selection as the environments changed around the world
fossils
preserved remains of organisms
descent with modification
natural selection changed more and more of the characteristics in a population until the members didn’t look like the ancestors, they created a new species.
biogeography
tells us where organisms live now and where they lived in the past. patterns suggest environmental factors for evolution
h0m0logous structures
non-similar organisms in related animals. these animals were from a common ancestor population whose members adapted to different habitats. these structures are now used in different ways
divergent evolution
results in homologous organs. the original population spreads out into various habitats that put different environmental selection pressures on the organisms. as organisms adapt to new/different environments their bodies change from the original populations and each offshoot population. (body similar on inside)
analogous structures
body parts that share common function but not structure. the animals are not closely related. don’t share many characteristics
convergent evolution
results in analogous structures. organisms not closely related have similar body parts because they are dealing with the same environmental pressures. (body similar on outside)
Vestigial structures
body parts inherited by ancestors but they have lost most or all of its original function. it didn’t matter if they were there or not. variants with or with out them were just as fit.
ex: wiggling ears, appendix, tail bone
embryological evidence for evolution
exists in the same patterns of embryo development by the HOX genes