Evolution And Darwin

Question 1

Aristotle

Answer 1

saw species as fixed or unchanging; thought they could be arranged on a linear scale of increased complexity.
Every species was perfect and impermanent.

Question 2

Linnaeus

Answer 2

used a 2 part binomial system: genus & species. Nested classification system; he grouped similar organisms into increasingly larger groups.

Question 3

Darwin

Answer 3

study of fossils. Changes in organisms occurs over time. From one layer to the next, we found new species & other species were no longer present. Greater dissimilarity between older fossils & living organisms than between newer fossils & living organisms.

Question 4

Natural Selection

Answer 4

mechanism that Darwin uses to explain the patterns of evolution. Described two observations:

1. Individuals of a population vary greatly in the herited traits. (Banded snails)
2. Species are capable of producing more offspring than can be supported by the environment.

Question 5

Inferences

Answer 5

1. Individuals whose inherited traits provide a high probability of survival and reproduction will leave more offspring in the next generation.
2. There is an accumulation of favorable traits in the population over time.

Question 6

Homology

Answer 6

Modifications in ancestral characters over time in related species with similar characteristics can lead to different functions of these characteristics (homologous structures)

Bone arrangement in all mammals are the same (used for different functions)

Suggest a common ancestor

Question 7

Embryonic structures

Answer 7

Vertebrates are very large groups - all have a post anal tail and pharyngeal pouches

Pharyngeal pouches become parts of ear and throat

Fish retain the tail, pharyngeal pouches become the gills

Question 8

Divergent evolution

Answer 8

gives rise to species and increases biodiversity

Distantly related organisms can also share characteristics; they don’t come from a common ancestor

Question 9

Convergent evolution

Answer 9

independent evolution of similar characteristics in different lineages
Ex: dolphin and the shark, have made similar adaptations, both predators of fish; had to evolve a very slim body shape, less resistance to water, both had to develop better methods of movement, tail is motor, fins and flippers for stearing. Not closely related at all. Shark is related to sting ray; dolphin, a mammal

Question 10

Galapagos mockingbirds

Answer 10

1. Different species are found on each island
2. All have similarities to a mockingbird species that’s found in Ecuador
3. Mockingbirds of Galapagos share a common ancestor from Ecuador
   Explains why two islands with similar environments located in different parts of the world are populated by species that are not closely related; those species resemble a common ancestor that came from a different mainland