Chapter 18

Question 1

Gene pool

Answer 1

All of the alleles of all of the genes of all the individuals in a population at a given time

Question 2

Population definition

Answer 2

Group of organisms of the same species that occupies a particular space at a particular time and can be potentially interbreed

Question 3

Allelic frequency defintion

Answer 3

The number of times an allele occurs within a gene pool

Question 4

5 assumptions for Hardy-Weinberg to work

Answer 4

No mutations, isolated population, no selection, large population and random mating

Question 5

Hardy Weinberg letters and meaning - p,q,p²,q²,2pq

Answer 5

p = probability of dominant allele
q = probability of recessive allele
p² = probability of homozygous dominant genotype
q² = probability of homozygous recessive allele
2pq = probability of heterozygous genotype
p²+2pq = probability of having dominant genotype

Question 6

Harry Weinberg 2 equations

Answer 6

p + q = 1.0
p² + 2pq + q² = 1.0

Question 7

Mutation definition

Answer 7

Sudden changes to genes or chromosomes

Question 8

Stabilising selection effect on graph

Answer 8

Peak gets narrower and higher

Question 9

Directional selection effect on graph

Answer 9

Peak stays the same abs shifts to what end is being selected for

Question 10

Disruptive selection effect on graph

Answer 10

Selected for two extremes

Question 11

species definition

Answer 11

a group of individuals with similar characteristics that can interbreed to produce fertile offspring

Question 12

causes of variation with phenotype

Answer 12

environment and genetic

Question 13

how does environment effect phenotype

Answer 13

the conditions where which an organism develops can cause variation

Question 14

how does genetics effect phenotype

Answer 14

mutations, meiosis (independent segregation and crossing over) and random fertilisation of gametes

Question 15

Speciation

Answer 15

in a given population under certain conditions a new species can arise from an existing specie

Question 16

allopatric speciation

Answer 16

geographical barrier causes the 2 populations to become completely separate. The mutations the populations undergo are separate and therefore if they join back and can no longer interbreed to produce fertile offspring they are said to be different species

Question 17

sympatric speciation

Answer 17

a new species arise from the same ancestral specie whilst living in the same area due to different habits and routines

Question 18

genetic drift

Answer 18

random change of allele frequency due to only some of each generation reproducing

Question 19

ecosystem

Answer 19

interaction between the community and the abiotic factors

Question 20

niche

Answer 20

a space within a habitat in which species survive

Question 21

community

Answer 21

the total of all the populations living together in a habitat

Question 22

carrying capacity

Answer 22

the size of a population an ecosystem can support

Question 23

interspecific competition

Answer 23

organisms from different species compete for resources

Question 24

intraspecific competition

Answer 24

organisms from the same specie compete for resources

Question 25

ecological succesion

Answer 25

change in a community over time

Question 26

primary succession

Answer 26

pioneer species, soil formation, colonisation by new species, altering abiotic conditions

Question 27

secondary succession

Answer 27

pioneer species, colonisation by new species, increased complexity, climax community

Question 28

percentage frequency =

Answer 28

number of quadrats in which the species was found/ total number of quadrats

Question 29

mark release recapture equation

Answer 29

population size = (total of first sample x total of second sample)/ marked organisms in second sample