Evolution Flashcards
What were Lamarcks beliefs on evolution
He believed that:
- Physical traits change with use and disuse
- These altered traits or acquired traits are inherited by offspring
- Ex a giraffe stretches its neck to reach food and its offspring inherit a longer neck.
Describe the process of Darwin’s evolution by means of natural selection
Which organisms are more fit depends on their environment. Nature selects traits to be passed on to the next generation
What is sexual selection
A form of natural selection in which animals develop features as a result of reproductive success. Ex
Being attractive to the opposite sex Intimidating, deterring or defeating same-sex rivals
Describe the process of artificial selection
Organisms naturally vary in phenotype
Humans select and breed organisms they “like”
What is the principle of super-position
sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top.
Explain relative dating
Deeper fossils are older than shallower ones
Explain a Homologous structure
Homologous Structures:
-Develop from same material using the same genes
-Indicate that the trait has a shared ancestor/heritage
-Become modified over time as mutations occurred
Ex: The limbs of humans, cats, whales, and bats
Explain a Analogous structure
Analogous Structures:
- Develop from different materials using different genes
- Indicate that the trait has a different ancestry/heritage
- Same selection pressure performs the same function (ex. Flight)
- Convergent Evolution = species independently evolve similarities (analogous structures) because they experience similar selection pressures.
Explain a Vestigial structure
Vestigial organs:
Homologous trait that has has no apparent purpose
-Indicate shared ancestry and relatedness – ancestor had that trait
-Show over time
Ex: The appendix is a non-functional organ in humans
Give an example of evolution
Rock pocket mice changing color over time to have some of the population be black to blend in with the lava rock and some be tan to blend into the sand
Misusing antibiotics can cause bacteria to build up resistance to it and the antibiotics can become un-helpful.
Describe Directional selection
Organisms at one end of the bell curve are more fit, so the entire population shifts to that side of the curve
Describe Stabilizing selection
Organisms in the middle are more fit, so the curve gets narrower
Describe Disruptive selection
Organisms at both ends are more fit than ones in the middle, so the curve may split in two
Describe Allopatric speciation
geographic separation causes groups to evolve separately until interbreed is not possible Ex. river forms, migration, mountain range forms
Describe Sympatric Speciation
no geographic separation, but groups evolve separately due to different lifestyles, preference time, habits…
