Vocabulary
What is fitness?
the ability of an organism to survive and reproduce
What are acquired traits? Give an example.
Traits that are not passed down to offspring. These are traits that an organisms got in its lifetime, such as scars.
What are homologous structures? Give an example.
Body structures that are similar among organisms of different species, but that have adapted because of a common ancestor. Ex: human arm, cat front leg, whale flipper, bat wing
What is the theory of common descent?
The idea that all living things arise from a common ancestor
What are mass extinctions?
when large amounts of organisms go extinct (cease to exist) in a short amount of time
What are fossils?
Preserved remains of organisms that can show organisms that are now extinct.
What is the use and disuse theory?
If you use an organ or body part, evolution will likely improve that structure. If you don't use that organ or body part, it is likely to either get small or disappear entirely.
What are analogous body structures? Give an example.
Body parts that serve similar functions, but not the same structure. They did not come from a common ancestor. Ex: shark fins, bird wings, dolphin flipper, human hand
How does genetic drift effect evolution?
Genetic drift involves changes in a gene pool when some individuals leave behind more descendants than others. This is not necessarily due to natural selection; it is by chance.
What is adaptive radiation?
When one single species evolves into several different forms
What is artificial selection?
Humans select the variations/traits provided by nature
What is the endosymbiotic theory?
A theory that proposes that eukaryotic cells formed from a symbiotic relationship among several different prokaryotic cells.
Structures that don't serve important functions. They are inherited from ancestors, but have lost much of their original size and function
What is the difference between directional natural selection and stabilizing natural selection?
Directional selection shows that phenotypes at one end of a bell curve have a higher fitness than at the other end. Stabilizing selection shows that individuals in the center have a higher fitness and are more likely to survive.
How is punctuated equilibrium different than gradualism?
Punctuated equilibrium involves long stable periods of time interrupted by rapid change caused by a change in the ecosystem. Gradualism involves slow and steady evolution.
What is a gene pool?
It consists of all genes present in a population, including all alleles for each gene
How does reproductive isolation prevent organisms from breeding with each other?
Organisms are kept apart by either their behavior, geography, or different mating seasons. Because of this, they do not breed, even though they physically could.
What is biogeography, and how does it relate to evolution
It is the study of where organisms live now and where their ancestors used to live. Patterns of fossils show how organisms have been distributed around the world and tell us how modern organisms may have evolved from them
What is speciation? (What is a species?)
The formation of a new species. A species is any group that can mate with each other and produce fertile offspring.
What is convergent evolution?
This occurs when similar environments make unrelated organisms look similar (such as what causes analogous structures).
What is the founder effect?
When immigration brings in new traits to an environment
What is survival of the fittest?
This is another phrase describing natural selection. It states that only the organisms best fit for their environment will survive. All organisms struggle for existence, and fitness is the result of adaptations.
How does the story of embryology help show evidence for evolution?
Similar patterns of embryological development (studying organisms at very early stages in life) show that organisms have descended from a common ancestor based on similarities.
What is genetic equilibrium, and why is it nearly impossible to take place?
Genetic equilibrium occurs when there is no natural selection, no gene mutations, random mating, large populations, and no migration. Basically, there are no changes in a population. This does not happen in nature because you can't prevent all mutations, organisms do not mate randomly, natural selection always takes place, and organisms migrate to find resources.
What did Miller and Urey try to prove/show in their experiments?
They tried to create life by creating an environment that they thought resembled early earth, but only ended up creating amino acids.