Population Dynamics

Question 1

p + q =

Answer 1

1

Question 2

5 things to maintain hardy weinberg equilibrium

Answer 2

1. large population: losing an individual’s genes (genetic drift) has less of an effect on large populations that small ones
2. random mating: mating by individuals is not determined by pheno/genotypes
3. no mutations: changing alleles present in the pool
4. no migration: movnt of alleles in/out (gene flow)
5. no natural selection: no env’t factor favoring one genotype over another

Question 3

p=

Answer 3

frequency of dominant allele in population

Question 4

q=

Answer 4

frequency of recessive allele in population

Question 5

p^2

Answer 5

% of homozygous dominant individuals (trait)

Question 6

q^2=

Answer 6

% of homozygous recessive individuals (trait)

Question 7

2pq=

Answer 7

% of heterozygous individuals (trait)

Question 8

mutation (agent of gene pool change)

Answer 8

random changes in genetic sequences. A source of genetic variation for natural selection

Question 9

gene flow (agent of gene pool change)

Answer 9

movement of individuals (alleles) from one population to another (immigration/ emigration)

Question 10

non-random mating (agent of gene pool change)

Answer 10

preferred phenotypes, increases those genotypes in pool

Question 11

Genetic drift (agent of gene pool change) 2 types

Answer 11

change in allele frequency in a breeding pop. due to random events. Small pop. may loose certain alleles (lack of mates, predation, etc): will have a greater impact on smaller groups

1. Founder Effect: a pop (gene pool) that’s formed by a small group of individuals (founders) that carry a representation (limited gene pool) of the original pop’s genes
2. Bottleneck Effect: quick reduction in pop (starvation, disease) causes a “bottleneck”, surviving pop produces less variant offspring

Question 12

natural selection (agent of gene pool change)

Answer 12

some individuals are better able to survive & reproduce than others. The offspring carry the successful genes

Question 13

speciation and 2 types of isolation

Answer 13

formation of a new species (lack of production of viable offspring)

1. Geographic isolation
2. Reproductive isolation

Question 14

geographic isolation

Answer 14

separation of individuals of the same species by physical barriers (ie sea, mountains)

• gene flow between 2 groups stops
• eventually individuals of one pop. can no longer interbreed with the other

Question 15

reproductive isolation

Answer 15

organisms in a pop can no longer mate to produce offspring, even though they live in similar envt
ex mutations not shared, mating seasons differ, reproductive organs

Question 16

relationship where both organisms (of different species) benefit

Answer 16

mutualism

eg. bees and flowers

Question 17

commensalism

Answer 17

one organism benefits, the other is unaffected

eg. shark and remora

Question 18

parasitism

Answer 18

one organism benefits and the other (host) is harmed

eg. tapeworm and buffalo

Question 19

intraspecific competition

Answer 19

between members of the same species

Question 20

interspecific competition

Answer 20

between members of different species

Question 21

6 defense mechanisms (against competition and predation)

Answer 21

1. camouflage
2. mimicry
3. biochemical (bitter/ toxic)
4. armor (thorns)
5. warning coloration
6. behavioral

Question 22

succession

Answer 22

process of replacement of organisms by a more successful group following a disturbance
pioneer species re/colonize (moss) –> intermediate/ seral species more successful and replaces pioneers –> community stabilizes when climax (most successful) community presides (hardwood trees)

Question 23

primary succession

Answer 23

occurs where there was no pre-existing soil

- glacier retreat, volcanic eruption

Question 24

secondary succession

Answer 24

occurs where soil has pre- existed before disturbance

ie fire/ earthquake

Question 25

carrying capacity (K)

Answer 25

the amount of individuals an envt can support based on resources etc

Question 26

environmental resistance

Answer 26

all the limiting factors that keep a pop from growing at its biotic potential, and determine the carrying capacity

Question 27

biotic potential

Answer 27

the max rate at which a pop can increase its size

Question 28

density dependent

Answer 28

effect increases as population increases
tend to be biotic
ie food suppy, disease, competition

Question 29

density independent

Answer 29

effect is the same regardless of pop size
tend to be abiotic
ie climate, natural disaters

Question 30

4 phases of carrying capacity graph

Answer 30

1. lag phase (slow/ no growth)
2. growth phase: exponential rise in pop
3. plateau/ stationary phase: climax community
4. decline phase: resources lack

Question 31

uniform pop distribution

Answer 31

order/ territories: competiton for resources

Question 32

random pop distribution

Answer 32

no order, attraction, or repulsion among members (lots of resources)

Question 33

clumped pop distribution

Answer 33

order; grouped in patches around an attraction

ie. watering holes/ to protect from predation (bison)

Question 34

J-shaped curve graph (exponential or unrestricted growth)

Answer 34

r selected species (closed pops)

Question 35

S shaped graph (logistic or restricted)

Answer 35

K selected species (open pops)

Question 36

characteristics of r selected species

Answer 36

J shaped graph
- small bodies
- numerous 
- many offspring, no care for offspring 
- high mortality rate
- reach reproductive age early
- short life span
eg bugs/ bacteria

Question 37

characteristics of K selected species

Answer 37

S shaped graph
- large bodies, fewer in #s
- few offspring, which require care
- low mortality rate
- reach reproductive age late, long life span
eg mammals, reptiles