Biology Unit 8 - Evolution

What is genetic drift and how does it affect evolution?

Significant changes in allelic frequencies of a population that drastically change that populations phenotypic makeup

What is sexual selection?

occurs when certain traits increase mating success fuels speciation

What is the difference between microevolution and macroevolution?

Microevolution: small changes in allelic frequency that can lead to major changes in a population (genetic drift---> founder effect)

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Macroevolution: Speciation over a much longer period of time (creation of new species)

What is the role of mutation in evolution

provides genetic variation

What is natural selection?

The idea that the fittest survive and pass along their traits to their offspring.

Natural selection 4 postulates

Variation must exist within a species/population of organisms. (earth always changing)

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Some variations are "better" or more advantageous than the others depending on the specific environment/niche that organism lives in (adaptations)

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Due to limited resources, not all organisms survive to reproduce. (Malthus)

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Those with the more favorable characteristics survive, reproduce, and leave more offspring.

What is fitness?

how well an organism can survive and reproduce in its environment

What are examples of evidence we can use to support the theory evolution? (know at least 4)

\-Genetic/molecular comparisons

\-vestigial organs (human tailbone)

\-homologous structures

\-analogous structures

\-viruses

\-immune system

\-pesticide/antibiotic resistance

\-Embryology

What are homologous structures?

Organisms who share a recent common ancestor and similar structures with different functions (Divergent evolution)

Ex: forearm of dogs, whales, humans

What are analagous structures?

Organisms who have no recent common ancestor, different structures, but the same function (Convergent evolution)

Ex: bird and bat wings

divergent evolution

when two or more species sharing a common ancestor become more different over time

convergent evolution

Evolution toward similar characteristics in unrelated species

What is biogeography and how does it provide evidence for evolution?

Determining if an organism would or would not thrive in a specific environment it shows that species have adapted to their environments and evolved because of it.

What is molecular biology and how does it provide evidence for evolution?

Seeing how many amino acids organisms have in common, provides evidence bc it shows how closely related organisms are to each other on a biochemical level

What is speciation and how does it relate to evolution?

Formation of a new species due to a separation and makes it so organisms who used to be of the same species unable to mate.

What is evolution?

Change over time; the process by which modern organisms have descended from ancient organisms

Dawin was

Fitzroy's conversationalist on their voyage of South America

Darwin's journey on the Beagle

1831-1836 only 2 months in the Galapagos\----\>finches

influences that shaped Darwins work

Malthus and Wallace

What is adaptation?

A trait that helps an organism survive and reproduce

What are vestigial organs?

Organs/bones that have lost their original function due to evolution and are now present in organisms as remnants

Ex: he human appendix or human/whale tailbone

Directional selection

Type of natural selection that favors individuals at one end of the phenotypic range, leading to a shift in the population's characteristics over time

Stabilizing selection

Type of natural selection that favors individuals in the middle of the phenotypic range, reducing variation

Disruptive selection

Type of natural selection that favors individuals on both ends of the phenotypic range, favoring variation over the average and/or leading to the splitting of a population into two distinct groups

What is wrong with the idea that organisms lose traits because they do not need them?

The trait is harming them or is making life harder, so the ones without the trait survive better and reproduce