biology Chapter 10-11

Question 1

Define evolution.

Answer 1

Change in a species over time.Process of biological change by which descendents come to differ from their ancestors.

Question 2

Who was the man behind evolution? What was the name of the ship he set sail on?

Answer 2

Charles Darwin-HMS Beagle

Question 3

Define species.

Answer 3

A group of organisms so similar to one another that they can reproduce and have fertile offspring.

Question 4

Who developed the present day classification system?

Answer 4

Carolus Linnaeus

Question 5

What are fossils? How do they support evolution?

Answer 5

Traces of organisms that existed in the past. They are very different by layers that are formed over time in rock

Question 6

Explain the differences among catastrophism,
gradualism
and uniformitarianism.

Answer 6

Catastrophism
- Georges Curvier-natural disasters such as floods and volcanic eruptions caused species to become extinct . New species then moved in from elsewhere accounting for the new species in the rock layers.

Gradualism
- James Hutton-Laying down of soil or Canyons, were not the result of large scale events, but were the result of slow changes over a long period of time. It has come to mean the gradual change of a species through evolution.

Uniformitarianism
- Charles Lyell-expanded Hutton’s theory of gradualism with his own observations that the geologic processes that shape earth’s landforms are uniform through time and have occurred at a constant rate and are ongoing. This greatly influenced Darwin.

Question 7

Define variation

Answer 7

is the difference in the physical traits of an individual from those of other individuals in the group to which it belongs.

Question 8

Define adaptation

Answer 8

-is a feature that allows an organism. To better survive in its environment. Adaptations can lead to genetic changes in population over time.

Question 9

Define artificial selection

Answer 9

humans make use of the genetic variations in plants and animals by acting as the selective agent. Humans determine which trait is desirable.

Question 10

Define heritability

Answer 10

is the ability of a trait to be passed down from one generation to the next.

Question 11

Define natural selection

Answer 11

is a mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals. In nature the environment is the selective agent.

Question 12

Define population

Answer 12

all the individuals of a species that live in an area

Question 13

What are the four main principles to the theory of natural selection? Describe each

Answer 13

Variation
-the heritable differences or variations that exist in every population. Result from differences in the genetic material of the organisms whether inherited or the result of a genetic mutation.

Overproduction
-having many offspring raises the chance that some will survive it also results in competition for resources.

Adaptation
-sometimes certain variations allow an individual to survive better than other individuals it competes against in the environment. More successful individuals are naturally selected.

Descent with modification
- Over time, natural selection will result in species with adaptations that are well suited for survival and reproduction in an environment. More individuals will have the trait in following generations as long as the environmental conditions continue to remain beneficial for the trait.

Question 14

Define fitness

Answer 14

is the measure of the ability to survive and produce more offspring relative to other members of the population in a given environment.

Question 15

Define biogeography

Answer 15

The study of the distribution of organisms around the world.

Question 16

What are the four main pieces of evidence that support the theory of evolution?

Explain how each supports evolution.

Answer 16

Fossils
-Organisms in different layers of rock are different possibly lower layers were more primitive versions.

Geography
-Darwin noticed the similarity between organisms on an island and the main land, but also that over time they had developed different traits to adapt to the new environment.

Embryology
-the similar features of embryos I very different organisms suggest evolution from a common ancestor.

Anatomy
-comparing the body parts of different species showed similarity of structure in parts in different organisms. This was strong evidence for common descent.

Question 17

Explain the difference between homologous and analogous structures. Give an example of each.

Answer 17

Homologous
-are features that are similar in structure but appear in different organisms and have different functions. Homologous structures are different in detail but similar in structure and relation to each other. Ex:forelimbs of tetrapod vertebrates. The forelimbs of humans, bats and moles have several bones that are similar to each other despite their different functions.

Analogous
-structures that perform a similar function, but are not similar in origin. Ex: Bat wings have bones but insect wings do not.

Question 18

What are vestigial structures? Give an example. How do they support the theory of evolution?

Answer 18

Remnants of organs or structures that had a function in an early ancestor. They are evidence of common descent and gradual change or shrinkage in unnecessary organs. Ex: Ostrich wings are small as they do not need them to run away from predators..

Question 19

Define gene pool

Answer 19

the combined alleles of all the individuals in a population.

Question 20

Define allele frequency

Answer 20

is a measure of how common a certain allele is in the population.

Question 21

What are the two main sources of genetic variation?

Answer 21

Mutation
-a random change in the DNA of a gene. This change can forma new allele.

Recombination
-New allele combinations form in offspring. Most combinations occur during Meiosis-the type of cell division need for sexual reproduction.. When gametes are made each parents alleles are arranged in new ways.

Question 22

What is normal distribution?

Answer 22

When the frequency values are graphed the result is a bell shaped curve. It is highest in the middle and decreases to either side.

Question 23

Explain the differences among directional selection, stabilizing selection and disruptive selection

Answer 23

Directional Selection
-a type of selection that favors phenotypes at one extreme of a traits range. An extreme phenotype that was once rare in a population becomes more common.

Stabilizing Selection
-the intermediate phenotype is favored and becomes more common in the population.

disruptive selection
-occurs when both extreme phenotypes are favored., while individuals with intermediate phenotypes are selected against by something in nature.

Question 24

What is microevolution?

Answer 24

is the observable change in the allele frequencies of a population over time. Microevolution occurs on a small scale -within a single population.

Question 25

Define gene flow

Answer 25

the movement of alleles from one population to another.

Question 26

Define genetic drift

Answer 26

changes in allele frequency due to chance. Causes a loss of genetic diversity in a population

Question 27

Describe the founder effect and the bottleneck effect.

Answer 27

Founder effect
-is genetic drift that occurs after a small number of individuals colonize a new area. The gene pools of these populations is often very different from the larger population.

Bottleneck effect
-genetic drift that occurs after an event greatly reduces the size of a population.

Question 28

Describe sexual selection

Answer 28

when certain traits increase mating success

Question 29

Describe Intrasexual selection

Answer 29

competition among males.

Question 30

Describe Intersexual Selection

Answer 30

traits that attract the opposite sex.

Question 31

What is Hardy-Weinberg equilibrium?

Answer 31

genotype frequencies in a population stay the same over time as long as certain conditions are met.
Populations that are not evolving:
• Very large population- No genetic drift can occur
• No emigration or immigration- No gene flow can occur
• No mutations-No new alleles can be added to the gene pool
• Random mating-No sexual selection can occur
• No natural selection-All traits must equally aid in survival.

Question 32

What are the 5 factors that lead to evolution? Describe each.

Answer 32

• Genetic Drift-Allele frequencies can change due to chance alone.
• Gene Flow- the movement of alleles from one population to another changes the allele frequencies in each
• Mutation-New alleles can form through mutation. Mutations create the genetic variation needed for evolution.
• Sexual Selection-Certain traits may improve mating success. Alleles for these traits in crease in frequency.
• Natural Selection- Certain traits may be an advantage for survival. Alleles for these traits increase in frequency.

Question 33

Define reproductive speciation

Answer 33

when members of different populations can no longer mate successfully with one another reproductive isolation occurs.This is the final step in becoming separate species.

Question 34

Define speciation

Answer 34

The rise of two ore more species from one existing species

Question 35

Explain the differences among geographic isolation, behavioral isolation and temporal isolation

Answer 35

• geographic isolation-Physical barriers that divide a population into two or more groups. This is the most commonly studied type of isolation
• behavioral isolation-isolation caused by differences in courtship or mating behaviors
• temporal isolation-when timing prevents reproduction between populations.Reproductive periods may change to a different time of the year or a different part of the day

Question 36

Explain the difference between convergent evolution and divergent evolution

Answer 36

Convergent is evolution towards similar characteristics in unrelated species and Divergent is when related species evolve in different directions and become increasingly different

Question 37

What is coevolution?

Answer 37

the process in which two or more species evolve in response to changes in each other.