Module 3

Question 1

Transmutation

Answer 1

The change of one species to another.

Question 2

Natural Selection

Answer 2

The mechanism of evolutionary change, in which genetic changes in frequencies of certain traits in populations are due to differential reproductive success between individuals

Question 3

Reproductive Success

Answer 3

How many offspring a creature or human has.

Question 4

Alfred Russel Wallace

Answer 4

Born into a modest family in 1823 and had little formal education. Beginning to work at the age of 14. In 1848 he joined an expedition to the Amazon and later explored parts of south-east Asia to collect bird specimens. In 1855 Wallace published a paper suggesting that species were descended from other species and that the appearance of a new species was influenced by environmental factors. In 1858 Wallace publishes another paper describing evolution as a process driven by competition and natural selection.

Question 5

The Conditions of Natural Selection

Answer 5

1. All species are capable or producing offspring at a faster rate than good supplies increase.

Question 6

The Conditions of Natural Selection

Answer 6

Basic Principle: Natural selection operates on individuals, favorably or unfavorably, but it is the population that evolves. The unit of natural selection is the individual. The unit of evolution is the population - this is because individuals don’t change over time, populations do.

1. All species are capable of producing offspring at a faster rate than good supplies increase.
2. There is biological variation within all species due to recombination due to sexual reproduction.
3. Since in each generation more offspring are produced than can survive due to limited resources, there is competition between individuals.
4. Individuals who possess favorable variations or traits have an advantage over those who don’t have time. The favorable trait increases the likelihood of survival and reproduction.
5. The environmental context determines whether or not a trait is beneficial - what is beneficial in one setting, may be a liability in another.
6. Traits are inherited and passed on to the next generation. Because individuals who possess favorable traits contribute more offspring to the next generation than others over time, such characteristics become more common in the population. Less favorable traits aren’t passed on as frequently and they become less common and eventually die out.
7. Over long periods of time, successful variations accumulate in a population, so that later generations may be very distinct from ancestral ones. In time, a new species may appear.
8. Geographical isolation also contributes to the formation of new species. As populations of a species become geographically isolated from one another, they begin to adapt to different environments. Over time, as populations continue to respond to different selective pressures, they may become distinct species.

Question 7

Selective Pressures

Answer 7

Forces in the environment that influence reproductive success in individuals.

Question 8

Fundamentals of Evolutionary Change

Answer 8

1. A trait must be inherited if natural selection is to act on it.
2. Natural selection cannot occur without population variation in inherited characteristics, and can only occur with variation that already exists
3. Fitness, which is differential reproductive success, is a relative measure that changes as the environment changes.
4. Natural selection can only act on traits that affect reproduction.

Question 9

Fertility

Answer 9

The number of offspring an individual within a population produces.

Question 10

Differential Net Reproductive Success

Answer 10

Individuals within a population will have varying amounts of success in the number of offspring that survive to reproduce themselves.