module 7

Question 1

what is a species

Answer 1

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

Question 2

what is a population

Answer 2

all individuals of a particular species in a particular place

Question 3

what is community

Answer 3

all the population of different species in a particular place

Question 4

what is a habitat

Answer 4

the place where organisms lives

Question 5

what is an ecosystem

Answer 5

a mix of different communities and habitats and how they interact based on abiotic and biotic factors

Question 6

what is ecological niche

Answer 6

an organisms role/position in an ecosystem- in terms of its interaction with abiotic and biotic factors

Question 7

why can 2 different species not occupy the same ecological niche

Answer 7

interspecific competition will take place for the limiting factors/resources (abiotic/biotic factors)- better adapted species will out compete the other= competitive exclusion principle

Question 8

how to sample plant species over large area

Answer 8

-obtain a map of the area
-divide map into grids
-select a large number of coordinates using running mean
-select a random set of coordinates using random number chart
-in each coordinate place a quadrat
-measure abundance of the plant species in each quadrat= frequency or percentage cover
- calculate average for the whole area

Question 9

how to sample plants species along a path

Answer 9

use a transect
place a tape along the path, count number of plants touching tape
OR
place a tape along a path and at regular intervals place a quadrat, measure abundance within the quadrat ( belt transect)

Question 10

phenotype

Answer 10

the expression of the genetic constitution and its interaction within the environment

Question 11

chromosome

Answer 11

a thread like structure made of protein and dna and contains the genetic information

Question 12

allele

Answer 12

an alternate version of a gene

Question 13

genotype

Answer 13

the genetic constitution of an organism

Question 14

locus

Answer 14

the position of a gene on a chromsome

Question 15

genome

Answer 15

the complete set of genes in a cell

Question 16

gene

Answer 16

a selection of dna that codes for a polypeptide

Question 17

diploid

Answer 17

cells where the nucleus contains 2 sets of chromosomes

Question 18

proteome

Answer 18

the full range of proteins that a cell is able to produce

Question 19

homozygous

Answer 19

condition in which the alleles of a particular gene are identical

Question 20

haploid

Answer 20

a cell with only 1 set of chromosomes

Question 21

heterozygous

Answer 21

condition in which the alleles of a particular gene are different

Question 22

dominant allele

Answer 22

an allele that is always expressed in the phenotype

Question 23

co-dominance allele

Answer 23

both alleles of 1 gene in a heterozygous organism are expressed in the phenotype

Question 24

recessive allele

Answer 24

the allele is only expressed if 2 copies are present

Question 25

allopatric speciation

Answer 25

result of geographical isolation. eg, mountains

Question 26

sympatric speciation

Answer 26

no geographical barrier. eg, same plants start flowering at different times of the year due to mutation

Question 27

formation of species generic mark scheme

Answer 27

in each population there is variation caused by mutation
in each population the environments differ
‘’ there is competition
‘’ the best adapted to survive and reproduce
pass on advantageous alleles
frequency of allele increases
2 populations are now different species and cannot reproduce successfully

Question 28

evolution definition

Answer 28

how a species becomes better adapted to its environement

Question 29

genetic variation

Answer 29

mutation
crossing over
independent assortment
random fertilisation
( all produce new combinations of alleles)

Question 30

genetic variation

Answer 30

mutation
crossing over
independent assortment
random fertilisation
(All produce new combinations of alleles)

Question 31

environmental factors of variation

Answer 31

eg sunlight
influences the way an organism gene to be expressed

Question 32

evolution generic mark scheme

Answer 32

competition (preditation and disease) results
in some individuals better adapted
those individuals with advantageous phenotypes are more likely to survive and reproduce and pass on the alleles
frequency of these alleles will increase

Question 33

3 types of pf selection

Answer 33

directional
stabilising
disruptive

Question 34

pedigree charts

Answer 34

this shows the inheritance of a particular gene through a number of generations
(Never write skipped generation in an exam)

Question 35

hardy Weinburg equation

Answer 35

p+q=1
p^2 + 2pq + q^2 = 1

Question 36

monohybrid cross

Answer 36

Monohybrid inheritance is when a phenotype or trait is controlled by a single gene
3:1 ratio

Question 37

dihybrid cross

Answer 37

Dihybrid inheritance is when two characteristics are studied and is determined by two different genes that are present on two different chromosomes at the same time
9:3:1:1

Question 38

recessive epistasis

Answer 38

Recessive epistasis occurs when the presence of
a recessive allele prevents the expression of
another allele at a second locus. Recessive
epistasis gives the ratio of 9:3:4

Question 39

dominant epistasis

Answer 39

Dominant epistasis is when a dominant allele at one locus completely masks the alleles at a second locus. Dominant epistasis gives a ratio of
12:3:1

Question 40

hardy Weinburg principle

Answer 40

The Hardy-Weinberg Equation can be used to estimate the frequency of alleles in a
population and to see whether a change in allele frequency is occurring in a population over time

Question 41

in order for hardy Weinburg equation to work the following must be true

Answer 41

no mutation
large population size
mating must be random
no migration
no selection