BIO EXAM 1

Question 1

What is evolution?

Answer 1

The process by which different organisms change, adapt, or diversify their genetic composition over successive generations

Question 2

How do scientists determine whether evolution is occurring in a population?

Answer 2

By tracking allelic frequencies in populations and if said populations are not in Hardy-Weinberg equilibrium

Question 3

What is the Hardy-Weinberg equilibrium?

Answer 3

A theorem that explains why a population is not comprised of a dominant genotype.
It states that when a population is in equilibrium, the genotypic frequencies will remain proportionally balanced.

Question 4

What are the requirements for H-W equilibrium?

Answer 4

1) No selection
2) No mutation
3) No migration
4) Small population
5) Random mating

Question 5

What are the 3 kinds of selection?

Answer 5

1) Disruptive selection- two extremes are favoured. Ex. birds’ beaks sizes
2) Directional selection- One extreme is favoured. Ex. Industrial melanic moths in popullted areas
3) Stabilizing selection- Intermediete traits are favoured. Ex. Average human baby weight

Question 6

What mechanics contribute to evolution?

Answer 6

1) Mutation
2) Gene Flow
3) Natural selection
4) Nonrandom mating
5) Genetic Drift

Question 7

Natural Selection

Answer 7

THe process by which organisms that are best equipped to survive in their environment, get to reproduce.

Question 8

Niche

Answer 8

The role an organism plays in a community

Question 9

Gene Flow

Answer 9

Movement of alleles between populations, usually with migration

Question 10

Genetic Drift

Answer 10

Random fluctuation in allele frequencies by chance. I.e. natural disaster

Question 11

Adaptation

Answer 11

The process by which a species or population becomes better suited to its environment

Question 12

Reinforcement

Answer 12

In speciation, the process by which partial reproductive isolation is increased by selection against mating between members of the two populations, eventually resulting in complete reproductive isolation

Question 13

Adaptive Radiation

Answer 13

One species rapidly evolves to fill multiple niches

Question 14

Convergent Evolution

Answer 14

Process whereby distantly related organisms independently evolve similar traits

Question 15

Sympatric Speciation

Answer 15

The differentiation of populations within a common geographic area into species

Question 16

Subspecies

Answer 16

A geographically defined population or group of populations within a single species that has distinctive characteristics

Question 17

Allopatric Speciation

Answer 17

The differentiation of geographically isolated populations into distinct species

Question 18

Reproductive Isolation

Answer 18

Any barrier that prevents genetic exchange between species
PREZYGOTIC:
1) Ecological isolation
2) Behavioral isolation
3) Temporal isolation
4) Mechanical isolation
5) Prevention of gamete fusion

POSTZYGOTIC:
1) Hybrid inviability or infertility

Question 19

Biological Species Concept

Answer 19

The concept that defines species as groups of populations that can breed and produce fit offspring- is reproductively isolated

Question 20

Ecological Species Concept

Answer 20

The distinction among species is maintained by natural selection (each species has adapted to its own specific part of the environment)

Question 21

Phylogenic Species Concept

Answer 21

Species are defined by examining their evolutionary history in populations

Question 22

Artificial Selection

Answer 22

Selective breeding of desirable traits that get to reproduce as chosen by humans

Question 23

What is a fossil?

Answer 23

A preserved remains of a once-living organism

Question 24

3 Conditions for a fossilization to occur

Answer 24

1) Organisms must be buried in sediment
2) The calcium in bone or other tissue must mineralize
3) Surrounding sediment must harden to form rock

Question 25

What is a transition fossil?

Answer 25

A fossil that exhibits both traits from ancestral and present-day organisms

Question 26

Examples of two transition fossils

Answer 26

Archaeopteryx- Traits of modern-day birds (feathers) and ancient dinosaurs (Teeth, bony tail, and carnivorous features) Pakicetus- Traits of modern-day whale (skull) but land-dwelling and four limbs

Question 27

Central dogma

Answer 27

DNA → mRNA → protein; only flows in one direction

Question 28

How does natural selection promote speciation?

Answer 28

It increases reproductive isolation as different species select for different adaptations and works against the fitness of hybrids

Question 29

How does gene flow work against speciation?

Answer 29

With incompletely isolated populations, gene flow is an intermediate for genotypes and the two populations lose their genetic distinctiveness/erase their differences

Question 30

Extinction

Answer 30

The process for species or populations to die off

Question 31

How does extinction occur?

Answer 31

When species die off because of environmental forces, overexploitation, or evolutionary changes

Question 32

How does molecular evidence support the theory of evolution?

Question 33

Pleiotropy

Answer 33

When one gene codes for more than one traits