Biology Unit 7 Evolution - Review and Practice Packet

Biology Unit 7 Evolution - Review and Practice Packet

Name: ______Period: ______

Biology Unit 7 Evolution - Review and Practice Packet



  1. How do we define evolution? **Be sure to include in your definition whether individuals evolve or populations**
  1. Describe WHAT each of these causes of evolution is and HOW each contributes to the process of evolution.

Cause / Description and HOW it effects evolution:
Genetic Variation
Sexual Preference
Environmental Changes
  1. Describe natural selection ANDdescribe an example of natural selection. THIS MEANS YOU MUST EXPLAIN THE EXAMPLE, NOT JUST LIST IT!


  1. To the right shows the 3 types of selections that can occur through natural selection. Under each picture, describe/define the phenotype selection depicted:
  1. How do adaptations contribute to survival and reproductive success? List an example.
  1. Some adaptations can include camouflage and mimicry. State how each help an organisms survive below:

Camouflage =

Mimicry =

  1. Complete the chart below to review your understanding of Charles Darwin (continues on the next page):

Focal Questions / Your Description/Response:
Who was Charles Darwin?
What did Charles Darwin do and where did he do it?
What two major contributions (observations) did he make with regard to evolution?
  1. What was Lamark’s Theory and state why it is wrong?
  1. What is the ultimate result of natural selection? (HINT: Your explanation should include the term “allele frequency”/It may act on phenotypes over time; however, think about what is it ultimately changing?)
  1. TWO-PART QUESTION: What type of interaction occurs when limited resources are available for organism to use? How does this interaction impact an organism’s ability to survive and reproduce?
  1. How do we define a species? ______
  2. List and DESCRIBE the three main causes of speciation. (HINT: THESE ARE ALL TYPES OF ISOLATION)
  1. TWO PART QUESTION: What are homologous structures? Describe an example. THIS MEANS YOU MUST EXPLAIN THE EXAMPLE, NOT JUST LIST IT! **Be sure to state whether this is evidence of a common ancestor or not!**
  1. What is descent with modification?
  1. What do we mean by the “gene pool”?
  1. Describe & Give an example for the 4 main forces of evolutionary change:

Force / Explanation/Example
MUTATION / Does this process increase or decrease genetic variation? ______
GENETIC DRIFT / Does this process increase or decrease genetic variation? ______
GENE FLOW / Does this process increase or decrease genetic variation? ______
NATURAL SELECTION / Does this process increase or decrease genetic variation? ______

Evidence of Evolution Practice:

Evidence of Evolution. P. 423-429. Match the type of evidence to its description.


______17. Different organisms share similar structures that have very different functions, or have remnants of structures/organs that had a function in the past.

______18. In DNA sequencing, the more closely related two organisms are, the more similar their DNA.

______19. Fossil organisms found in bottom (older) layers are more primitive than those in the upper (newer) layers; often times, these extinct fossils resembled modern life.

______20. During the early stages of life, embryos of very different organisms appear to be very similar. As they continue to develop, they become increasingly different.

style______21. Different habitats favor different traits and can establish separate populations that have a common ancestor.

22. Use the rock layer diagram to the right to answer

Questions A - D.

  1. Which layer is the oldest? ______
  1. Which layer is the youngest? ______
  1. Would a fossil from layer F be older or younger than a fossil from layer B? ______
  1. How does looking at rock layers and fossils help scientists to understand how organisms have changed over time? ______

23. Organisms that are closely related may also have physical similarities before they are even born! Take a look at the six different embryos to the right. Does this suggest an evolutionary relationship? ______Explain how these embryos can be used as evidence of a common ancestor between each of these six organisms.

24. To the right showing various wings is an example of what type of structure? ______Do these organisms have a common ancestor? ______

25. Use the chart to the leftcomparing the amino acid sequence of various organisms to answer the following questions.

A. Which species is more closely related to a human & why?

B. Which species is least related to a human & why?

26. Explain below how we use Biogeography as evidence for evolution”

27. Using the picture to the right, give a reason as to how species C & E are more closely related that species C & D, even though C and D are technically inhabiting the same island?

Part 2: Apply and Extend

Below is a series of pictures representing changes in a population of cacti over many generations.

  1. Figure 4 shows the situation several months later. What has happened?

a.Why would a deer be more likely to eat the left cactus than the right cactus?

  1. In figure 3, the right cactus has flowers, but the cactus that has been eaten by the deer is too damaged to make flowers?

b.Do you think that evolution by natural selection is occurring in this cactus population? Explain why or why not.

c.What adaptation seems to increase the fitness of the cacti on the right? How do you think this adaptation increases the ability of cacti on the right to survive and reproduce?

  1. You have seen, in all of these examples, how natural selection favors those individuals with certain traits. Based on what you have seen AND on what you know about genetics, answer the following questions:
  2. Is the dominant characteristic ALWAYS the one that is most seen in a population? [think about our work with human genetics
  1. Assume that in the cactus population, the presence of thorns is a recessive characteristic. Will the frequency of the allele for thorns become greater or lesser over time?