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NAME & PERIOD:_______________________________Chapter 15 Study Guide: Due Monday (4/13) Test Tuesday (4/14)
Section 1
1. On Darwin’s voyage, what was interesting about the tortoises on
the different islands?
The tortoise was native to 7 of the 19 Galapagos Islands. Shell size
and shape vary between populations. On islands with low vegetation,
tortoises have short necks and domed shells. On islands with tall
vegetation, tortoises have long necks and saddle-like shells. Why would
there be predominantly different variations of tortoise on different
islands?
2. In order to better understand what was going on, Darwin observed
artificial selection which is …
Darwin’s term for the selective breeding of organisms selected for
certain traits in order to produce offspring and have those traits (i.e.
breeding dogs, cattle, crops, pigeons).
3. What is natural selection? What are the four principles (include
descriptions).
Natural select ion is the theory of evolution developed by Darwin,
based on four ideas:
Excessive reproduction- population produces more offspring than can
survive- better chances for more beneficial variations to arise
NAME & PERIOD:_______________________________Chapter 15 Study Guide: Due Monday (4/13) Test Tuesday (4/14)
Variations- differences between individuals in a population (ie tall or
short, ear lobe attached unattached)
Inheritance- variations can be passed on to the next generation
Advantages of specific traits in an environment- “survival of the fittest”
some traits allow the organism to live and have more offspring than an
organism that does not have them
4. Give an example of natural selection (include the principles in your
description).
Species: Unideer
Overproduction: unideer have many children in hopes of creating a
variation that helps each new generation survive
Variations: soft hooves, hard hooves
Reproductive Advantage: unideer population had to scale a mountain,
soft hooves fell off and died (contributed no offspring to the next
generation), hard hooves survived and their trait had the highest fitness
Section 2
5.
How do fossils help support the theory of evolution?
The kinds of animals and plants found as fossils change through time.
The fossil record can document the transition from one species to
another (ex- fossil showing feathers of modern birds and teeth and
bony tails of reptiles).
6. How do homologous structures help support the theory of
evolution?
NAME & PERIOD:_______________________________Chapter 15 Study Guide: Due Monday (4/13) Test Tuesday (4/14)
The structures are anatomically similar but may not have the same
function (such as a human arm and a porpoise fin). Their similarity
suggests a common ancestor.
7.
How do vestigial structures help support the theory of evolution?
Vestigial structures are reduced forms of functional structures in other
organisms (i.e. a kiwi has wings, but they are too small to be used for
anything). Provides support for shared ancestry and evolution.
8.
Why do analogous structures NOT imply shared ancestry?
Analogous structures can be used for the same purpose and be
superficially similar in construction (i.e. eagle wing and beetle wing) but
are not inherited from a common ancestor.
9. How does comparative embryology help support the theory of
evolution?
Vertebrate embryos exhibit homologous structures during certain
phases of development but become totally different structures in the
adult forms.
10. How does biochemistry help support the theory of evolution?
Molecules in species with a recent common ancestor should share
certain ancient amino acid sequences. The more closely related a
species, the greater the number of sequences that will be shared.
11. How does geographic distribution help support the theory of
evolution?
NAME & PERIOD:_______________________________Chapter 15 Study Guide: Due Monday (4/13) Test Tuesday (4/14)
Animals could evolve similar adaptations to similar environments but
are not closely related.
12. (True/False) Adaptations are positive changes and increase a
species’ fitness.
TRUE
13. Compare and contrast camouflage and mimicry.
Camouflage and mimicry are both types of adaptations. Camouflage
helps a species to blend in with their environment. Mimicry allows one
species to evolve to resemble another species.
Section 3
14. List the 5 mechanisms of evolution and write a brief description of
each.
Genetic drift- change in allelic frequencies in a population as a result of
chance (i.e. founder effect, bottleneck)
Nonrandom mating- organisms mate for desirable traits, out of
convenience, close proximity
Mutation- random change in genetic material, may result in harmful,
helpful, or no change in traits
Gene flow- migration, animals/plants moving between populations,
increases genetic variation, decreases differences between populations
Natural selection-
15. Compare and contrast founder effect and bottleneck.
NAME & PERIOD:_______________________________Chapter 15 Study Guide: Due Monday (4/13) Test Tuesday (4/14)
Both are examples of genetic drift. The founder effect occurs when a
small sample of a population settles in a locations separated from the
rest of the population. A bottleneck occurs when a population declines
to a very low number and then rebounds (like after a natural disaster).
16. What are the four types of natural selection? Draw a graph for
three of them and explain what is going on in the graph.
Stabilizing, directional, disruptive, sexual
Stabilizing- both extremes selected against
Directional- one extreme selected against
Disruptive- mean selected against