By: Mrs. Tokmajian & Mrs. Jackson

1. Define genetic drift: Change in allele frequencies due to chance
Define both types of g.d. and give examples:
Bottleneck Effect: Random event decreases population and genetic variation in population. Ex.: Overhunting of elephant seals
Founder Effect: Individuals leave old population and start new population with decreased genetic variation. Ex.: Owl
Island

Exchange or transfer of alleles/genetic information between populations

-Organisms with traits that make them wellsuited to their environment are more likely to survive, reproduce, and pass their beneficial traits on to the next generation.
-Natural selection increases species diversity
(led to 2 types of tortoises on diff. islands those with long necks/legs, those with short necks/legs)

4. Explain how environment can cause a shift in the phenotype of a species (think of the black and white pocket mice in the desert).
-Environment can cause an increase in the number of individuals with beneficial phenotypes and a decrease of individuals without beneficial phenotypes.
-Black pocket mice increased due to phenotype helping them blend in with new dark environment from black hardened lava rock while white mice decreased.

-Mutations
-Combination of gametes formed by meiosis during sexual reproduction

6. Which produces more genetic variation: sexual or asexual reproduction?
Sexual reproduction. Asexual reproduction produces genetically identical offspring with NO variation.

When two populations of a species can no longer successfully mate - leads to speciation.

Behavioral isolation: differences in courtship or mating behaviors.
Geographic isolation: physical barriers that divide a population into two or more groups.
Temporal isolation: timing prevents reproduction between populations.

8. What type of selection favors phenotypes at both extremes and selects against intermediate phenotypes?
Disruptive selection
Selection FOR brown and blue, AGAINST intermediate (brownish bluish)

9. What type of selection favors phenotypes at only one extreme?
Directional selection

10. What type of selection favors intermediate phenotypes and selects against extreme phenotypes?
Stabilizing

11. DNA & proteins can be used to determine evolutionary relationships. 3 different species have a similar protein. Explain how you could tell which 2 species are less closely related by looking at the protein.
Compare the amino acid sequences of the proteins - species with more differences are l ess closely related

Embryology compares similarities in developmental stages of different organisms to provide evidence that they share a common ancestor.
Embryo
Fetus

13. Explain what vestigial structures are and what they tell us about evolution (think of wings on flightless birds).
Structures that had a function in an ancestor but don’t in modern day organisms.
Ex.: Wings on flightless birds show they evolved from ancestors that flew. They’ve since evolved adaptations to travel efficiently in other ways.

14. Explain what homologous structures are and how they provide evidence for evolution
Homologous structures are structures in different organisms that share similar structures but perform different functions - provides evidence of a common ancestor. Ex.: forelimbs of humans and cats.

-Variation
-Overpopulation
-Adaptation
-Descent with modification
(VOAD)

1. The 5 levels of ecology in order are listed below. Next to each category name, write the biotic or abiotic factor that belongs with each level.
1. Organism: Alligator
2. Population: 5 Alligators
3. Community: Alligators, Birds, Grass, Frogs, Trees
4. Ecosystem: Alligators, Birds, Grass, Frogs, Trees, Soil, Water, Sunlight
5. Biome: Temperate Deciduous Forest

2. Bacteria plays a major role in nitrogen fixation in the nitrogen cycle.
Bacteria in the soil and in plant roots fixing the nitrogen into ammonia so that plants can readily use it. How does nitrogen get into the soil so that bacteria can use it?
Answer : Besides fixation of atmospheric nitrogen, decomposers break down dead plants and animals.
This process returns nitrogen to the soil so that bacteria can fix it for plants.
*Also returned through animal urine
(not shown on diagram)

3. How is the carbon cycle related to the oxygen cycle?
Answer : In the carbon cycle, plants take in carbon. Plants receive this carbon in the form of carbon dioxide from the process of photosynthesis.
Remember: CO2 + H2O + light
(all inputs of photosynthesis)

4. Draw a food chain and a food web and explain the similarities and differences between them. A.: Food web = many connected food chains
Food Chain
Food Web
Food Web

Question 4 Continued:
Similarity : A food web contains multiple related food chains. (Both show feeding relationships)
Difference : Food chains show one feeding relationship, food webs show multiple feeding relationships.

5. Symbiotic relationships between organisms are relationships where the 2 organisms have close interactions with each other usually in a positive way. Name and explain the 3 types of symbiotic relationships.
A. Mutualism : Both organisms benefit from the relationship. Ex: bee and flower
B. Commensalism : One organism benefits and the other is neither helped nor harmed. Ex: clownfish and sea anemone
C. Parasitism : One organism benefits from the relationship while the other is harmed. Ex: tick and human

6. Define the terms Biotic and Abiotic and give examples.
A. BIOTIC : Living (animals, plants, etc)
B. ABIOTIC : Non-Living (water, light, soil,)

7. According to this food web, if the grasshoppers were removed, how would the other organisms be affected?
Answer : Most obvious answer is that lizards and hawks would go down.
*Which populations would be affected if grass was removed?
ALL OF THEM

8. Give an example of competition between two organisms and predation between two organisms.
Answer :
Competition : 2 male lions fight for a female, or for food. 2 species of plants fight for the same sunlight and soil.
Predation: A fox hunts, kills, and eats a rabbit.

9. Use the graph to determine when this population reached its carrying capacity?
Answer : Approximately on Day 22

10. According to the diagram, if lizards were removed, what would happen to the locusts and the snakes?
Answer : Snakes would DECREASE because they have nothing to eat. Locusts would INCREASE because nothing is eating them. *Ecosystem thrown off balance

11. Using your knowledge of renewable resources from class, explain 2 ways in which humans can reduce the waste/pollution produced on Earth.
Answer : Reduce CO2 emissions to cut back on global warming, use renewable energy like solar energy to cut back on burning fossil fuels like oil and gas. Recycle to cut down on waste,etc.

12. Give 2 reasons why invasive/non-native species can be harmful to a new area.
Answer : They have no natural predators so they can easily take over a new area. They take space and food away from the native species that lives there.

Variety of living things – different species live in different environments