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Flashcards in Evolution Deck (16):

What are the two core principles of evolution?

Descent with modification
Natural selection


What is descent with modification?

Particular groups or species undergo modification in successive generations, sometimes resulting in the formation of new, separate species


What is natural selection?

Process in which differential adaptation of organisms to their environment selects those traits that will be passed on with greater frequency
The primary and most significant of several processes that result in life evolving


What is adaptation?

As a result of natural selection, organisms change (evolve) over time


Understand and provide examples of convergent evolution

the independent acquisition of the same biological feature in unrelated lineages
features arising through convergent evolution are termed analogies, whereas homologies have a common evolutionary origin
Shark (fish)
Ichthyosaur (reptile)
Dolphin (mammal)


What is different between convergent evolution and homologous structures?

Traits arising through convergent evolution are termed analogous structures, whereas homologous structures have a common evolutionary origin


List categories and examples of “homology” evidence that species are related, including structural, developmental and molecular.

homologies: morphological or biochemical traits that are similar
Functions vary but underlying structure
morphology of embryos (pharyngeal slits)
h = hind limb bud in
dolphin embryo


What are vestigial features in humans?

The existence of vestigial traits supports the idea that traits that are selected against may be minimized, and give evidence of the ancestral condition.  Vestigial traits imply a different ancestral form and thus support the idea that species change over time.
I.E. Tails


Describe Darwin’s insights into descent with modification and natural selection.

Darwin saw a pattern: these animals were related to an ancestral species found on the mainland of South America.
Many of the species he saw had common mainland ancestors, but those on the islands had diverged into separate species


Discuss the evidence that species change over time, including…

extinction means living world is not “fixed”
fossil record, species not static


Discuss the evidence that species change over time, including…

“law of succession”
striking resemblance in geographic proximity, and in geological layers


Discuss the evidence that species change over time, including…
Vestigial traits

coccyx, appendix?
gene families (gene duplication followed by shift in function)


Discuss the evidence that species change over time, including…
contemporary response to environment

drug resistance, pesticide resistance, herbicide resistance


Define natural selection

natural selection: Individuals with certain heritable traits will survive and reproduce more, leading to a change in the traits of a population.


Explain why Darwin’s theory of natural selection is a process component to the theory of evolution.

Darwin’s major contribution: recognizing a process for descent with modification, natural selection.
Darwin recognized and expressed natural selection, the process that could explain the pattern of “descent with modification.”


Understand how scientific arguments against evolution in the late 1800’s were reconciled

Age of the earth (it had to be old in order for evolution to proceed from single cells to complex organisms)
Genetic mechanism (for transmitting adaptations to subsequent generations)