Download Evolution Unit Guide ANSWERS

EVOLUTION UNIT GUIDE ANSWERS
Read: Chapters 10.2 – 10.5, 11.1-11.3, 11.6, 12.1-12.2 (www.my.hrw.com username: astudents602
password: n2s7v)
Watch (Supplemental Resource): All videos can be found on youtube. Stated Clearly (What is
Natural Selection?) Bozeman science (Evolution)
Class websites: www.rebeccawheatley.weebly.com (Regular) or
www.wheatleypreapbiology.weebly.com (Pre-AP).
Listen and Look: Here is a list of key terms you will hear and see during the reading and video. You will
be completing a vocabulary activity using these terms.
Ecology Review Vocabulary:
 Ecosystem- a community of organisms and their abiotic environment
 Limiting factor-an environmental factor that prevents an organism or population from reaching
its full potential of distribution or activity
 Biosphere- The part of Earth where life exists; includes all of the living organisms on Earth.
 Trophic Level- Level of nourishment in a food chain
 Succession- the process by which one community replaces another
 Commensalism- Ecological relationship in which one species receives a benefit but the other
species is not affected one way or another
 Consumer- An organism that eats other organisms or organic matter instead of producing its own
nutrients or obtaining nutrients from inorganic sources.
 Producer-organism that obtains its energy from abiotic sources such as sunlight.
 Scavenger- organism that feeds on dead or decaying matter.
 Decomposer- An organism that feeds by breaking down organic matter from dead organisms (
fungi and bacteria).
 Predation- An interaction between 2 species in which one species, the predator, feeds on the
other species, the prey.
 Mutualism- Ecological relationship between two species in which each species gets a benefit from
the interaction
 Parasitism- Ecological relationship in which one organism benefits by harming another organism
 Symbiosis- a close ecological relationship between two or more organisms of different species
that live in direct contact with one another.
Evolution Vocabulary:
 Evolution = change in a species over time
 Natural Selection = mechanism by which individuals that have inherited beneficial adaptations
produce more offspring on average than do other individuals.
 Population = all of the individuals of a species that live in the same area.
 Homologous structure = body part that is similar in structure on different organisms but
performs different functions.
 Analogous structure = body part that is similar in function as a body part of another organism
but is structurally different.
 Embryology = study of embryos (stage of development after the fertilized cell implants into the
uterus but before the cells take on a recognizable shape).
 Vestigial
 Fossil Record = history of life as documented by fossils.
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Adaptation = inherited traits that is selected for over time because if allows organisms to better
survive in their environment.
Paleontology = study of fossils or extinct organisms.
Biogeography = study of the distribution of organisms around the world.
Variation
Artificial Selection = process by which humans modify a species by breeding it for certain traits.
Fitness
Convergent evolution = evolution toward similar characteristics in unrelated species, resulting
form adaptations to similar environmental conditions.
Divergent evolution = evolution of one or more closely related species into different species;
resulting from adaptations to different environmental conditions.
Coevolution = process in which two or more species evolve in response to changes in each other.
Extinction = elimination of a species from Earth.
Adaptive Radiation = process by which one species evolves and gives rise to many descendent
species that occupy different ecological niches.
Recall and Review: Use the videos and your textbook to help you answer the following questions in
your BILL.
Section 10.2
1. Describe the difference between a variation and an adaptation.
Variations are simply differences in phenotypes whereas adaptations are variations that give you
an advantage over other individuals.
2. Explain why tortoises of the same species look different.
Because they live in different areas and those organisms posses variations that allow them to be
most successful in their particular area.
3. List two things Darwin learned from his trip to the Galapagos.
Organisms within the same species have a lot of variety, those variations depend upon the
environment where they are living.
Section 10.3
4. State the four main principles of natural selection.
1. Overproduction
2. Competition
3. Variation and Adaptation
4. Reproduction
5. Briefly explain how each of the above principles is necessary for natural selection to occur.
In order for there to be a reason for natural selection, there have to be more individuals present
than the environment can support. Because of this, there is competition between the organisms.
Those with variations that give them an advantage will be more likely to survive and reproduce.
Section 10.4
6. Describe the four sources of evidence for evolution upon which Darwin based his ideas on
common ancestry.
A. Molecular DNA similarities
B. Fossil Evidence
C. Embryology
D. Comparitive Anatomy
7. Why are vestigial structures considered critical evidence of evolution? Give an example of a
vestigial structure.
Because they are structures that we still possess in our bodies but yet there is little to no function
needed for them anymore. An example is the small pelvis found in snakes and whales.
8. Describe the difference between homologous and analogous structures.
Homologous structures are those in which the structure is similar but they have a completely
different function. For example, bat wings and human arms. Analogous are those in which the
structure is very different but they are used for the same function, bat wings and insect wings.
Section 10.5
9. Explain how paleontology is important to evolutionary biology.
Paleontology is important to biology because the fossils are a good way to examine extinct
organisms to see what relationships existed a long time ago.
10. How has molecular genetics, combined with paleontology, added to our understanding of
evolution?
Molecular genetics allows us to make comparisons of the DNA structure and protein created from
it. For example, we can examine the amino acids that make up a particular protein and count the
number that are the same and different for a variety of species. This could then be used to figure
out which ones are the most closely related. Combining this with the ability to examine fossils can
help to map out evolution.
11. Describe how similar protein comparisons of cells in two species can suggest a close evolutionary
relationship.
The more similar the proteins then the more similar the DNA since the protein is transcribed and
translated from the DNA.
Section 11.1
12. Why does genetic variation increase the chance that some individuals in a population will survive.
Because some variations are more beneficial in the environment than others.
13. Describe two main sources of genetic variation.
Sexual reproduction and mutations
Section 11.6
14. Explain what it means to say that natural selection is not random.
Natural selection is not random because with each generation, variations present are chosen for,
meaning that certain variation are carried on to next generation because they provide an
advantage for the individual.
15. How does coevolution shape two species over time?
If you have two species that are dependent upon each other, as one species changes, the other
must change also. For example, if a bee pollinates a particular kind of flower and over the course
of many generations the shape of the flower changes, the bee must also change so that it can
continue to “fit” into the flower.
16. Describe the difference between convergent and divergent evolution.
Convergent evolution is when you have two species that do not share a common ancestor but do
share similar physical characteristics. It is the result of the environment choosing particular
individuals based on the characteristics needed to be successful.
Divergent evolution is when you have two species that are from a common ancestor. They have
branched out from the ancestor based on the characteristics necessary for their environment.
Section 12.1
17. Why are so few complete fossils discovered?
Very few fossils form because conditions have to be just right or the organism will decompose.
Section 12.2
18. What is the usefulness of categorizing Earth’s history into the geologic time scale?
It enables us to make comparisons of organisms that have lived over different years and make
predictions on how new species evolved.
Sample Questions
19. The loss of habitat in a forest region has caused some plant species to become extinct, while others
survive. The process by which some plant species survive and others do not in a changing
environment is best explained by
a. Natural selection
b. Law of segregation
c. Biological magnification
d. Alternation of generations
a.
b.
c.
d.
20. Which of the following is evidence to support the idea that two different species might have a
common ancestor?
Their fossil were discovered in the same location
Many of their genes are the same
Their methods of respiration are alike
They use the same means of locomotion
a.
b.
c.
d.
21. The bones in the wings of a bat are the same as the bones found in the paws of raccoon, though
their function is quite different. The similarity is evidence that the bat and the raccoon
Hunt for the same prey
Live in the similar habitat
Are about the same size
Share a common ancestor
a.
b.
c.
d.
22. Which of the following is biochemical evidence for evolution?
Embryonic human hemoglobin is different from adult human hemoglobin.
Hemoglobin in humans can vary between different individuals.
Human hemoglobin is more similar to chimp hemoglobin than mouse hemoglobin.
Human hemoglobin is different than mouse hemoglobin.