Unit 6 Evolution & Classification Study Guide Lesson 6.1 – Origins of Life & Natural Selection 1. Describe what scientists believe the earliest organisms on Earth were like. 2. Explain how scientists believe the first organisms changed over time. 3. The theory of Natural Selection was first suggested by ______________________________ 4. The driving force between evolution is the interaction between organisms and their ____________________. 5. Explain each of the conditions that lead to the evolut

Unit 6 Evolution & Classification Study Guide 

Lesson 6.1 – Origins of Life & Natural Selection 

1. Describe what scientists believe the earliest organisms on Earth were like. 

2. Explain how scientists believe the first organisms changed over time. 

3. The theory of Natural Selection was first suggested by ______________________________ 

4. The driving force between evolution is the interaction between organisms and their ____________________. 

5. Explain each of the conditions that lead to the evolution of a population below: 

a. Genetic Variation 

i. What are the causes of genetic variation? 

b. Overproduction 

c. Competition 

d. Adaptation 

i. Why is this also called survival of the fittest? 

6. Explain how peppered moths illustrate Darwin’s theory of natural selection. 

Lesson 6.2 – Evidence of Evolution 

1. What does the fossil record tell biologists about evolution? 

2. What do structural similarities suggest about the evolutionary history of organisms? 

a. What are homologous structures? How are the structures below examples of homologous 

structures.? 

b. What are vestigial structures? Give an example of a vestigial structure. 

c. What is embryology? How do the embryos below provide evidence for evolution?     

d. What do molecular similarities tell biologists about the relationships between organisms? 

e. What are examples of molecular similarities biologists might study? 

Lesson 6.3 – Classification & Dichotomous Keys 

1. Place the following categories in order from largest (most general) to smallest (most specific): 

a. Class, domain, family, genus, 

2. What are the 6 kingdoms used to classify organisms? 

3. Summarize the key characteristics of each kingdom below. 

4. What information can be learned by reading a phylogenetic (evolutionary) tree? 

5. Use the phylogenetic tree below to answer the following questions: 

a. Which two species are most closely related? Explain how you know. 

b. Which species are extinct? How do you know? 

6. What are dichotomous keys? 

7. Use the dichotomous key below to name the shark shown. 

Dichotomous Key 

1. a. tail fins are horizontal…………go to 2 

b. tail fins are vertical…………….go to 3 

2. a. has teeth or tusk……………….go to 4 

b. has no teeth……………………Balaena mysticetus 

3. a. has gill slits behind mouth…….go to 5 

b. has no gill slits……………………Lepidosiren paradoxa

4. a. black with white underside…..Orcinus orca

b. tusk, gray with dark spots……Monodon monoceros

5. a. head is hammer shaped……..Sphyrna mokarran 

b. tail fins are half the body length…Alopias vulpinus

         Shark Name