Darwin and Diversity Flashcards
Explain how evolution is a fact.
Evolution has been observed and has definitely, undeniably occurred.
Explain how evolution is a theory.
The processes and mechanisms of evolution are debatable in regards to timing and methods, making this a theory.
What are the four lines of evidence for evolution?
Microevolution, macroevolution, imperfections, and molecular evidence.
What is microevolution?
A small change within a species over a short period of time.
What is macroevolution?
A large change between species over a long period of time.
How are imperfections proof of evolution?
Imperfections in the physical structures of organisms indicate their evolutionary history.
What is an example of a physical imperfection in whales and what does it indicate?
Whales have an unnecessary pelvis, which indicates that they are descended from terrestrial mammals.
What is an example of a physical imperfection in snakes and what does it indicate?
Snakes have vestigial hind limbs, which indicate that they are evolved from a lizard like creature.
Why is the appendix an imperfection in humans?
It is a remainder from when humans were unable to digest cellulose. It is now unnecessary, making it a physical imperfection.
Why are wisdom teeth an imperfection in humans?
Wisdom teeth used to be able to fit in our mouths, but no longer can as our jaw shapes have changed. They are now detrimental, making them physical imperfections.
What does the coccygael tail indicate?
The coccygael tail vertebrae are left over from when humans used a tail for balance and support.
What two things are used as molecular evidence for evolution?
Amino acids and nucleotide sequences.
What is a gene which is conserved across vertebrates?
The FoxP2 gene.
What is the FoxP2 gene used for? (3 things)
- Neural circuitry of the brain
- Sensory-motor information
- Learning of coordinated movements
What happens to mice which don’t have the FoxP2 gene?
They can’t navigate mazes
What happens to birds which don’t have the FoxP2 gene?
They can’t learn songs.
What happens to people who don’t have the FoxP2 gene?
They have very delayed speech development or never develop speech.
What four observations are Darwin’s theory of evolution based on?
- Variation exists between individuals within a population.
- Genetic traits are inherited from parents by offspring.
- More offspring are produced than the environment can support.
- Many offspring do not survive long enough to reproduce.
What two inferences are Darwin’s theory of evolution based on?
- Individuals with favourable genetic traits are more successful at reproduction and have increased survival rates.
- Differential reproductive success results in an accumulation of favourable genes.
Explain how lactose tolerance is an example of microevolution.
Domestication of cattle arose 5,000 - 10,000 years ago. People who were able to digest lactose could then use milk as a source of energy and nutrients, making them stronger and fitter. This lead to differential reproductive success and positive selection for lactose tolerance genes.
Define evolution.
Change in the genetic composition of a species over time. (aka descent with modification)
Define natural selection.
A process by which organisms with certain inherited traits have differential reproductive success due to those traits.
What are the four main misconceptions about natural selection?
- Individuals change within their lifetime.
- Natural selection occurs because of a desire / need to adapt.
- All individuals are equally fit.
- Acquired traits can be passed on to offspring.
Define sexual selection.
Selection based on phenotypical characteristics which make mates more desirable or increases an individuals ability to compete for mates.
Define intrasexual selection.
Intrasexual selection is selection which occurs within a sex. It selects for body size and weapons.
What is an example of intrasexual selection?
Male deer compete for mates through ritualised fighting, which selects for large antlers and large body sizes.
Define intersexual selection.
Intersexual selection is selection which occurs between sexes, usually when a male tries to attract a female mate. This selects for behaviour, colour, and ornamentation.
What is an example of intersexual selection?
Male birds of paradise use bright colourings and courtships displays to try attract mates.
How are adaptions based on sexual selection detrimental to organisms survival?
The elaborate structures selected for through sexual selection take energy to construct and make the individuals vulnerable to predation.
Define stabilising selection.
Selection for the mean and against the extremes.
What is an example of stabilising selection?
Birth weight in humans. Very small babies are more vulnerable to health complications while very large babies are a risk for deadly birth complications.
Define directional selection.
Selection against one extreme and for the other extreme. This results in the mean shifting.
What are two situations where directional selection could occur?
- Change in the environment
2. Migration to a new environment
What is an example of directional selection? (turkeys)
Turkeys have been artificially selected to have extremely large breasts. They can no longer breed naturally because of their large breast size.