Download Darwins 5 Points of Natural Selection

Evolution Study Guide
Name___KEY___________
My child is prepared for Friday’s Test and has completed this study guide ________________________
Vocabulary: Use the following words to fill in the blanks: genetic variation, mutation, adaptation, sexual
selection, evolution, theory, natural selection, artificial selection, genetic drift, migration (gene flow), and
reproduction. Some words may be used more than once.
1. In order for a population to evolve, organisms in the population must have differences or __genetic
variations__________.
2. There are 5 mechanisms that change the gene frequencies in a population. They are __gene flow_____ ,
____sexual selection_________, ______natural selection___, ____mutations______,__genetic drift_________.
3. gene flow__________________-The chance of an individual migrating to another population and sharing its
genes there.
4. _mutation____________________- A change in a DNA sequence, usually occurring because of errors in
replication or repair.
5. ___mutation_______________________ - The ultimate source of genetic variation.
6. __genetic drift_______ - The change in allele frequencies in a population due to random events like habitat
destruction which results in changes in successive generations.
7. ___natural selection___________ - A process of evolution in which traits that result in better fitness of an
individual survives to the next generation. Survival of the fittest!
8. ___natural selection________ - is defined as the process whereby organisms with the best genetic adaptations
will survive and reproduce.
9. __evolution_______ - Theory in which populations will inherit small changes over time.
10. A ___theory___________________ is more than an educated guess. It is a widely accepted set of explanations
of observations and phenomena.
11. __adaptation__________ - An inherited characteristic that increases the chance of survival
12. In ___artificial selection__________, human breeders, rather than the environment, select the variations of traits
to be passed to offspring.
13. Darwin provides a mechanism for evolution to occur. He proposed that _natural selection__
____________________ took place as individuals best suited to the environment survived and reproduced.
14. Charles Darwin realized that the measure of success for an organism was not only a long period of survival but
also successful _reproduction_______.
15. Every organism must either carry out ___reproduction______ or become extinct. ( A characteristic of all living
things)
Evidence of Evolution:
1___paleontology___________- The study of extinct Life.
 Fossil records show that species have changed over time. In ___relative _ dating, scientists compare fossils
found in different layers of rock to determine the relative age of an organism. In __absolute
(radioactive)__dating, scientist look at half-lives of element decay to determine the exact age of a fossil.
2. _Embryology_____________- The study of organisms at an early stage of development provides evidence of possible
common ancestors between two different species.
3. ___homologus structures___- Organs found on different organisms that have similar structures but have evolved
different uses for these structures.
4. __Vestigial Structures_- Organs or structures that have been reduced in size in an organism that suggests that they
adapted to life without their use.
Darwins 5 Points of Natural Selection
1. __Variation__________________- Organisms within a population will have differences.
2. Within variation, their will be a __favorable____ ___traits_________
3. __Overproduction______- More organisms will be produced than will survive.
4. Of those organisms that survive, they have a favorable trait that increased their chances of survival called
an___adaptation____.
5. Over time, the environment will have __selected____ a trait that will become more prevalent within the
population.
Short Answer:
Animals and plants have been selectively bred for generations to produce
certain desired phenotypes. This is an example of __artificial
selection_________________. This supports the theory of
_evolution_________________ because it shows how organisms can change.
Light
Phenotypes:
Dark
E
D
C
Use the peppered moth example to explain Darwin’s 5 points of evolution.
1. ___Variation__________ – populations have differences. What is the
variation in the peppered moth population? __dark and light______
2. Some variations are __favorable_____________. After the Industrial
Revolution, which phenotype is most favorable? __darker_________
3. __Overproduction______– More offspring are produced than survive. After
the Industrial Revolution, which phenotype survived at a greater rate? _darker
moths________
4. _Adaptations_________– those that survive are the ones with the favorable
traits
5. _Selection____________– the population will change over time as a result
of passing inheritable traits from adaptations. In time, most of the moth
population were of the ___darker__________ phenotype.
This diagram demonstrates the process of ___natural selection
___________________. It demonstrates that changes in the gene frequency of
a population can change the phenotypes of a population. Before the
introduction of the predator, each phenotype occurred in equal numbers in the
population. After the introduction of the predator the __darker______
phenotype is most common. This is because they were able to survive and
__reproduce___________ at a greater rate.
There are two ways that scientists date fossils. This picture represents
__relative_______ dating in which the position of fossils in rock layers are
used to determine age. Fossils in lower layers are _older_______ and fossils in
upper layers are ___younger_____. In this picture, layer __E__ is the youngest
layer and layer ___A_ is the oldest.
B
A
Darwin cited evidence for the theory of evolution. One of these is represented
by this diagram. It shows _Embryology______________- the study of
organisms at an early stage of development. The similarities in the
development of many organisms suggest an __evolutionary_______
relationship (common ancestor).
Another line of evidence cited in the theory of evolution is represented by this
diagram. It is an example of __Vestigial________ structures, body parts that
are reduced in size and unused in present day organisms.
Suggests that as body part was no longer needed in environment they were lost
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The diagram below shows _______Homologous__________structures, which
may not have the same use, but do have a common evolutionary origin, and
thus structure. These similarities in body parts suggest a ___Common
Ancestor______
__Carrying Capacity________ – the number of individuals that an
environment can support due to environmental pressures.
Explain what each point on the graph shows:
A: Individuals are dying and reproducing at the same rate
B: Population is slowly growing
C: Unlimited resources and not much competition, population is growing fast
F: Possible Answer: Population ran out of resources/ predator was introduced
At which point is the population increasing at the greatest rate? __C______
What caused this population to crash? __Disease/ natural disaster/ Predator
Graph 1: Rabbits Over Time
The graph shows ___population of rabbits meeting its carrying capacity
The carrying capacity for rabbits is __65__
During which month did the population of rabbits reach carrying capacity? __August
During which month were the rabbits in exponential growth? __June_____
Using the cladogram provided, which species (indicated
by letters) are now extinct? ____P,O, L,H, D,C___(6)
Determine the ancestors of the following present day
organisms:
For J: (there is 4) __I, G, E, A__________
For K: (there is 4) _I, G, E, A__________
For M: (there is 3) __F, E, A, (another one not labled)
Study the picture to the left. A population of insects is sprayed with a new
insecticide. Most of the insects are killed but a few survive. In the next
generation, spraying continues, but many more of the insects are unaffected by
the insecticide than the first spraying. Which of the following BEST explains
these results?
a. The insecticide caused a mutation in the species.
b. A few insects in the first population were immune and passed
this trait to their offspring.
c. The insecticide caused a side effect of immunity that was
passed on to the next generation of insects.
d. The insects learned to fight off the insecticide.
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