BIOL2 Exam 1

Question 1

True or False: Evolution is goal-oriented—
toward the more complex.

Answer 1

False

Question 2

True or False: Evolution creates new forms of life by dramatic mutations.

Answer 2

False

Question 3

True or False: An organism can evolve during
its lifetime

Answer 3

False

Question 4

True or False: An organism can influence the evolution of its structures in response to the environment.

Answer 4

False

Question 5

True or False: Evolution is a completely
random process.

Answer 5

False

Question 6

What is Evolution?

Answer 6

The change in organisms throughout
Earth’s history. Descent with modification

Question 7

Georges Cuvier

Answer 7

Fossils are a record of change over time caused by catastrophic
events.

Question 8

James Hutton

Answer 8

Gradualism. Geological features came from slow, continuous processes.

Question 9

Charles Lyell

Answer 9

Uniformitarianism. Geologic processes progress at the same rate as today. therefore the Earth is extremely old.

Question 10

Erasmus Darwin (Charles Darwin’s Grandfather)

Answer 10

natural philosophy on evolution wrote ideas that “form minute” slowly acquired complexity over time.

Question 11

Jean Baptist de Lamarck

Answer 11

Adaptation –extinct species have been replaced by descendants with
new features.

Question 12

Evolution theory

Answer 12

• Developed by Charles Darwin & Alfred Wallace
• All present life is related through “descent with
  modification”
• Natural selection is the mechanism for
  evolution.

Question 13

Evidence Supports Evolution Theory

Answer 13

Fossil Records: Many extinct species (much greater than alive today!)
Homology: structures derived from a common ancestor (but may be
modified for different functions)
Vestigial structures: remnants of ancestral (homologous) structures with no present
adaptive function
Convergence Evolution: unrelated species have similar adaptations (analogous
structures) under similar environmental conditions

Question 14

Ways to define “species”

Answer 14

• Morphological species: Look alike
• Ecological species: a set of organisms adapted to a specific
  set of resources
• Phylogenetic species: smallest distinct set of organisms that share a
  common ancestor
  -Biological species (our default): a set of populations whose members potentially interbreed in nature to produce fertile, viable young and do not successfully interbreed with other such groups.

Question 15

Biological Species Concept

Answer 15

• share the same gene pool
• are reproductively isolated

Question 16

Prezygotic barriers

Answer 16

prevent fertilization

Question 17

Examples of prezygotic barriers

Answer 17

• habitat (ecological) isolation
• temporal isolation
• behavioral isolation
• mechanical isolation
• gametic isolation

Question 18

Postzygotic barriers

Answer 18

act after a hybrid zygote is
formed

Question 19

Effects of post-zygotic barriers

Answer 19

• reduced hybrid viability
• reduced hybrid fertility
• hybrid breakdown

Question 20

Allopatric Speciation

Answer 20

How geographic separation makes a new species
Isolated population diverges genetically due to natural selection
and/or genetic drift
During allopatry, biological reproductive barriers evolve, creating
separate species.

Question 21

Sympatric Speciation

Answer 21

–Speciation occurs in the same geographical area
- Habitat differentiation may lead to sympatric speciation

Question 22

autopolyploidy

Answer 22

• polyploid of one individual
  –gametes of polyploid individuals not compatible with “parent” species gametes

Question 23

allopolyploidy

Answer 23

– polyploid of hybrid of 2 species

Question 24

Discrete Genetic Variation

Answer 24

single gene locus
–2 or more alleles

Question 25

continuous variation

Answer 25

–phenotypes produced by combined effects of 2 or more genes

Question 26

Population:

Answer 26

a group of interbreeding individuals in the
same area, somewhat isolated from other groups

Question 27

Microevolution

Answer 27

Any change in population allelic or genotypic frequency
over time

Question 28

–The H-W equilibrium

Answer 28

• IF a large population reproduces sexually at random,
• THEN the genetic frequencies should not change in the next generation
  (remains in equilibrium)

Question 29

The H-W conditions:

Answer 29

1. no mutations
2. mating is random
3. no selection (equal survival)
4. very large population size
5. no gene flow in or out

Question 30

–The H-W equation (population at equilibrium):

Answer 30

if p = frequency of dominant allele
and q = frequency of recessive allele
and p + q = 1,
then in any generation:
p^2 + 2pq + q^2 = 1

Question 31

What CAUSES
microevolution
to happen?

Answer 31

1. Natural Selection
2. Genetic Drift
3. Gene Flow

Question 32

Natural Selection

Answer 32

– Acts non-randomly on phenotypes of
individuals
–Changes in allelic & genotypic frequencies of
populations non-randomly
– Always leads to the adaptation of the population to current environment

Question 33

Genetic Drift

Answer 33

• genetic frequency changes due to random
  events
• often reduces diversity
  Bottleneck Effect / Founder Effect

Question 34

Gene Flow

Answer 34

• alleles move in/out of population
• tends to add diversity to the population
• tends to reduce differences between
  populations

Question 35

Relative Fitness

Answer 35

–Fitness is relative to other individuals
in the population
includes: survival, finding mates, & the # healthy, fertile offspring
“fittest” = best reproductive success

Question 36

Forms of Natural Selection

Answer 36

• Directional Selection: shifts character’s mean value
  to one direction
• Disruptive selection (Diversifying selection) intermediates are less fit
  than extremes
• maintains diversity
  –Stabilizing selection
  intermediate types fitter
  than extremes
• variation reduced