Week 9: Evolution

Cartoon:

There are many misconceptions about evolution and this cartoon shows one nicely. The beaver would like to cut down more trees for food and building his/her lodge.  So he thinks very hard and wills  himself to have a chainsaw paw. Explain what is wrong with this idea?

Learning Objectives 

By the end of this module, students should be able to

• • Define evolution and answer the following questions
    •  What is a gene? What is a gene pool? What reshuffles genetic information from generation to generation? What is evolution in terms of frequency of genes? What are 5 different mechanisms that can lead to evolution? Which of these introduces new genes? Which of these leads to adaptations? What is an adaptation? What is natural selection in terms of genes, variations and adaptation to environment?
  • Explain the requirements for natural selection 
    •  Why does their need to be variability in the population for natural selection to occur? Why does that variability need to be heritable? Why does their need to be difference in reproductive success? How does the environment determine which traits are most favorable?
  • List the origins of genetic variation
    • What are mutations? What is the relation between mutations and protein shape, folding and function? How does the environment affect the impact of a mutation on the organism? How do mutations happen in day to day life of cells? Why are mutations random? How does sexual reproduction lead to genetic variation in a population? What is the impact of meiosis (crossing over and independent assortment) on the genetic variation in a population? What is the impact of random fertilization? 
  • Explain how natural selection leads to adaptations
    • What is the definition of natural selection? What is the definition of an adaptation?  How does the environment determine which genetic variations will lead to reproductive success? How does this lead to a match between the environmental conditions and the structure, function and behavior of organisms? Be able to give an example. 
  • Explain  how natural selection leads to speciation
    • What are reproductive barriers? How does natural selection in different populations of the same species lead to reproductive barriers? If there is enough time and large enough reproductive barriers, why does that create new species? How do we define a species? 
  • Explain how natural selection, speciation lead to the diversity we see on earth today.
  • Identify misconceptions about evolution and explain the correct information

Study Guide Questions 

1. Explain how evolution occurs by natural selection and leads to adaptations, using a specific (real) example. Make sure to include

• • • definition of evolution,
    • definition of natural selection
    • requirements for natural selection
    • the role environment plays in natural selection
    • a definition of adaptation

2. Explain how evolution leads to speciation, using a specific (real) example. Make sure to include

• • • definition of evolution
    • definition of species
    • definition of speciation
    • the role of reproductive barriers
    • different types of reproductive barriers
    • the results of a reproductive barrier on genetic differences between populations 

3. For each of the following misconceptions, explain the error and restate the correct information.

• • • Evolution is random
    • Organisms control their adaptations 
    • Organisms can control their adaptations to human environmental changes
    • The strongest survive
    • All traits are adaptive
    • Organisms inherit acquired traits
    • Individuals evolve

Powerpoint slides