Evolution Unit
Test Review
1. Explain how the following scientist contributed to Darwin’s theory of Natural selection.
a. Lyell
 Explained the process that shaped the Earth are still taking place and take
millions of years to occur.
b. Hutton
 He proposed that earth is shaped by geological forces. He estimated the
Earth to be Millions not thousands of years old.
c. Lamarck
 He proposed the process of Inheritance of acquired traits. His ideas were
flawed, but he was the first to propose a mechanism explaining how
organisms change over time.
d. Malthus
 Predicted the human population will grow faster than the resources needed
to survive (competition).
2. Describe the following evidences for evolution.
a. Vestigial Structures (organs)
 A structure that had a function at one time, but over time through the
process of evolution, they lost the function. AN common example is the
appendix of humans.
b. Fossil Record
 Seeing remains of ancient organisms that were once on the earth, but are
now extinct, allows scientist to see how similar organisms have changed over
time.
c. Embryology
 Scientists look at the embryos of organisms which show the similarities in
development which gives evidence of a common ancestor.
d. DNA
 The more similarities found in the DNA the closer related an organism is.
3. Describe an example of speciation.
 The Galapogas Finches are an example of speciation. They adapted beaks
that were fit for the available food. Since they look at beak size for finding a
mate, this created reproductive isolation that led to new species.
4. How does reproductive isolation lead to speciation? How does temporal and
geographical isolation lead to reproductive isolation?
 When a species no longer can bread together they are considered two
different species. Temporal isolation is when you have two groups of a
species that have a difference in their mating rituals so they no longer breed
which leads to reproductive isolation. Geographical isolation is when a
species can no longer physically mate because geographic divisions that leads
to reproductive isolation. Ex- a canyon, road, mountain. Those species will
evolve separately.
5. Explain radioactive dating.
 Scientist use the ratio of radioactive elements to the stable isotope to
determine the age of the sample by using the half-life of the radioactive
isotope to calculate the age.
6. What is genetic variation?
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Genetic variation describes naturally occurring genetic differences among
individuals of the same species.
Without genetic variation, some of the basic mechanisms of evolutionary
change cannot operate.
There are three primary sources of genetic variation, which we will learn
more about:
o Mutations are changes in the DNA. A single mutation can have a large
effect, but in many cases, evolutionary change is based on the
accumulation of many mutations.
o Gene flow is any movement of genes from one population to another
and is an important source of genetic variation.
o Sex can introduce new gene combinations into a population. This
genetic shuffling is another important source of genetic variation.
7. How does genetic variation help an organism evolve in a changing environment?
 If a species has a lot of variation then it will be better prepared for a changing
environment. It is very likely that one of the variations will be better suited for
the changing environment. If a species has no variation than a whole species
could be wiped out by a changing environment.
8. Describe the four eras of the geological time line.
 Precambrian Time:
o 90% of the Earth’s history occurred during this time. Few fossils from this
time have been uncovered because most organisms were soft-bodied.
 Paleozoic Era:
o Large diversity of organisms especially marine organisms.
o As much as 95% of the complex life in the oceans died in the mass
extinction that occurred at the end of this era.
 Mesozoic Era:
o Age of the dinosaurs
o Marked by the appearance of flowering plants.
o Another mass extinction that wiped out half of the organisms occurred at
the end of the Mesozoic.
 Cenozoic Era:
o Mammals evolved adaptations that allowed them to live in a variety of
environments.
o Modern humans live during this era
o Current Era
9. What is biodiversity?
 The sum total of the genetically based variety of all organisms in the biosphere.
10. Explain how biodiversity in an ecosystem can occur?
 Adaptations of populations to differing environments.
11. What is gene shuffling?
 It is the process that produces millions of different combinations of genes.
12. What is Natural Selection? Give an Example.
 Survival of the fittest. Those organisms better fit for an ecosystem will survive
and pass their traits on to their offspring.
 Example: peppered moths, Galapagos finches, Galapagos tortoise, Galapagos
iguanas
13. What is Artificial Selection? Give an example.
 Nature provides the variation, and humans select the variations that they find
useful in organisms. Then they breed the selected organisms to get a specific
outcome.
14. Explain the 3 domain system.
 There are three domains: Bacteria, Archaea, and Eukarya.
 Based on a molecular clock model.
15. What are the levels of classification from broadest to most specific?
 Kingdom, Phylum, Class, Order, Family, Genus, Species
16. Explain the scientific name of an organism.
 A system developed by Carolus Linnaeus.
 It is a two-word naming system called binomial nomenclature.
 The first word is the Genus and is always capitalized.
 The second word is the species and is not ever capitalized.
 The name is always written in italics.
17. Describe Darwin’s observations on the Galapagos Islands.
 He saw that so many plants and animals seemed so well suited for whatever
environment they inhabited.
 He also saw that not every organism lived in every place on the Earth.
 He also noticed that living organisms were only part of the story. HE looked at
fossils to tell the rest.
 He was especially interested in the Galapagos Islands and how the many species
seemed to be fit to the specific island environment they lived in.