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Biology Study Session- Evolution II
Name: _answer key_____________
For each question below, explain whether the evidence is comparative anatomy (homologous structures), comparative anatomy
(analogous structures), DNA analysis, fossil record, embryology, biogeography, or vestigial structures. Some may not be used. Then,
using complete sentences, explain why it is evidence of evolution, or that life changes over time.
Example:
1.
Humans, chimpanzees, whales, and bats all have the same bones in their arms, fins, or wings.
a. What type of evidence is this? ______comparative anatomy (homologous structures)__
b.
2.
Scientists find fossilized bones of a huge animal that doesn’t exist today.
a. What type of evidence is this? _______fossil record____________________________
b.
3.
Why is this evidence of evolution? Shows that the organ had a use in an ancestor
600 different species of cichlid fishes have diversified in Eastern Lakes in Africa. Fish lineages evolved to take advantage of
different foods (including insects, algae, mollusks, small fish, large fish, even fish scales).
a. What type of evidence is this? _______biogeography____________________________
b.
1.
Why is this evidence of evolution? Shows that organisms have a common ancestor since they look similar early on
in development
Humans, rabbits, and zebras all have an appendix, an extra piece in their digestive system, although in humans it’s much
smaller.
a. What type of evidence is this? _________vestigial structure__________________________
b.
7.
Why is this evidence of evolution? Even though these organisms are not closely related,
they have similar structures with the same function, showing organisms adapt to their
environment
Pigs, turtles, and lizards look similar in early embryonic development.
a. What type of evidence is this? _______embryology____________________________
b.
6.
Why is this evidence of evolution? Shows that organisms are related by similarities in DNA
Honey possums lick nectar from flowers using a long tongue made of soft muscle. Butterflies lick nectar from flowers using
a long tongue made of hard protein.
a. What type of evidence is this? ________analogous___________________________
b.
5.
Why is this evidence of evolution? Shows organisms have changed over time
The human gene for your muscle protein is different from monkey muscle protein in 4 places and different from a
chicken’s gene in 25 places.
a. What type of evidence is this? _______DNA analysis/molecular biology____________________________
b.
4.
Why is this evidence of evolution?
This is evidence of evolution because if all these animals have the same bones, they probably all evolved
from one creature that had those bones a very long time ago. Some of its descendants evolved (or
changed) into humans, and other evolved into whales or bats or chimpanzees.
Why is this evidence of evolution? Shows that organisms adapt to where they live
Hardy Weinberg describes populations that are not evolving. They are in equilibrium if these conditions are met:
a. _______no migration (no immigration/emigration)________________________________________________
b.
______no mutations_________________________________________________
c.
___________large population____________________________________________
2.
d.
___________random mating (no sexual selection)____________________________________________
e.
___________no natural selection____________________________________________
Read the synopsis or analyze the photo to determine which of the five factors that push a population out of
equilibrium is being represented.
a. _______mutation______________________A new coat color is introduced into a population of rabbits.
b.
_________non-random mating_________________Female guppies tend to mate with red colored males more often.
c.
________________genetic drift____________Before a tornado a frog population was 25% brown and 75% green. A
tornado rips through the land killing many frogs. The frog population is now 40% brown and 60% green.
d.
_____________________gene flow________200 Russians move into Finland.
e.
_______________natural selection____________Some weeds are sensitive to insecticide and die thus not passing
down their genes. Weeds with the allele for insecticide resistance are selected for.
Types of Natural Selection
Type of
Natural
Selection
Disruptive
Directional
Stabilizing
3.
Description
Graph of Distribution
Individuals with a
more extreme form of
trait have higher
fitness
Shifts normal
distribution to the
right or left
Having average form
of trait has highest
fitness
Normal distribution
becomes narrower, see
less individuals at the
extremes
Individuals with any
extreme trait has a
higher fitness and
most likely results in
two new species
Now have 2 curves in
distribution
Determine what type of Selection is occurring in these prompts. Grey is most common at the start
a. ___________stabilizing___________ Color of a moth can either be white, black, or grey. After many generations the
grey moth is the most favorable in its environment so it becomes the most frequent trait.
b.
________disruptive_________________ Color of moth can either be white, black or grey. The white moth blends in
with the birch trees while the black moths blend in with the shadows. Over time the white and black moths
BOTH become the most frequent trait.
c.
__________directional_________________ Color of moths can either be white, black, or grey. Pollution turns the
trees dark making the black moths better camouflaged than the grey or white moths. Over time the black
moths become the most frequent trait.
Types of Speciation
Allopatric Speciation
Sympatric Speciation
Definition:
Definition:
Speciation due to geographic isolation
Speciation due to reproductive isolation
Prezygotic
Definition:
Reproductive isolation occurs before fertilization
Postzygotic
Definition:
Reproductive isolation occurs after fertilization,
offspring are born, but they are infertile