Genetics

Question 1

What is the importance of meiosis

Answer 1

sexual reproduction

crossing over leads to genetic variation

Question 2

How does genetic variation occur

Answer 2

independent segregation of homologous chromosomes

new combination of maternal and paternal alleles by crossing over

Question 3

what is a gene

Answer 3

length of DNA that codes for a polypeptide

Question 4

what is a locus

Answer 4

position of gene on a chromosome

Question 5

explain independent segregation

Answer 5

chromatids arrange randomly on the equator
homologous pair line up
4 pairs therefore 4 options

Question 6

when does crossing over occur

Answer 6

between pro and metaphase 1

Question 7

when does independent segregation occur

Answer 7

anaphase 1 and 2

Question 8

how does prophase 1 leads to variety

Answer 8

crossing over is a random process and alleles

Question 9

Why does selective breeding decrease genetic diversity

Answer 9

decreases the number of alleles

Question 10

What is eugenics

Answer 10

selective breeding in humans

Question 11

why do populations stay constant even though there’s more food

Answer 11

intraspecific competition within species and natural selection increases desirable allele frequency which, after e period of time, becomes the most common allele

Question 12

what are the two types of selection

Answer 12

directional and stabilising

Question 13

what is directional selection

Answer 13

favours individuals that vary in a direction from the mean when selection pressure applies such as a change in the environment

Question 14

what is stabilising selection

Answer 14

favours average individuals, preserving characteristics of a population in a maintained environment

Question 15

What will a stabilising selection do

Answer 15

eliminate extreme alleles

Question 16

what 3 things can natural selection be based off

Answer 16

anatomical changes, physiological changes or behavioural changes

Question 17

What is a genetic bottleneck

Answer 17

when a population suffers a drop in numbers and survivors possess fewer alleles than the original population

Question 18

what is a disadvantage of having fewer alleles

Answer 18

less likely to adapt to changes making them vulnerable

Question 19

give an example of genetic bottlenecking

Answer 19

Northern elephant seals that were hunted close to extinction

Question 20

Name three things that increase genetic variability

Answer 20

migration, meiosis and mutations

Question 21

name three things that decrease genetic variability

Answer 21

natural selection, diseases and natural disasters

Question 22

give an example of industrial melanism

Answer 22

light peppered moths in the industrial revolution

Question 23

what is the founder effect

Answer 23

a few individuals from a population start a new population with a different allele frequency than the original, more diverse population

Question 24

how do we write the genus and species

Answer 24

underlined

Question 25

if the species is unknown what do we write

Answer 25

sp

Question 26

what is the genus written with

Answer 26

a capital letter

Question 27

what is the theory and practice of biological classification called

Answer 27

taxonomy

Question 28

what are the two types of classification

Answer 28

artificial and phylogenetic

Question 29

what is artificial classification

Answer 29

divides organisms according to differences that are useful to us at the same time

Question 30

what is phylogenetic classification

Answer 30

based on the evolutionary relationship between organisms and their ancestors

Question 31

what is a homologous characteristic

Answer 31

a characteristic that has similar evolutionary origins but may not have the same uses now eg pentadactyl limb

Question 32

what are the three domains

Answer 32

bacteria archaea eukarya

Question 33

what characteristics does bacteria have

Answer 33

unicellular 70s chromosomes murein walls

Question 34

what characteristics does archaea have

Answer 34

no murein single cell DNA more similar to bacteria

Question 35

what characteristics does eukarya have

Answer 35

80s ribosomes membrane bound organelles no murein in cell walls

Question 36

on a phylogenetic tree where is the oldest species

Answer 36

at the base

Question 37

what are the older species on a tree

Answer 37

extinct

Question 38

name 5 reasons why it is hard to define species

Answer 38

they are not fixed and evolve artificial selection causes much variation many species are extinct with no fossil records some species dont reproduce sexually some species are isolated from one another and cannot interbreed

Question 39

what does courtship allow

Answer 39

animals to recognise their own species and identify a mate that is capable of breeding allows easy inheritance of genes

Question 40

what happens in a ritual

Answer 40

male does the action and the female responds making a stimulus response chain

Question 41

biodiversity meaning

Answer 41

variety in living organisms in a particular area

Question 42

what is species diversity

Answer 42

the number of different species within one community

Question 43

what is genetic diversity

Answer 43

the variety of genes possessed by the individuals that make up one species

Question 44

what is ecosystem diversity

Answer 44

range of different habitats within one particular area

Question 45

what does biodiversity reflect

Answer 45

how well an ecosystem functions

Question 46

the higher the species diversity index the what

Answer 46

more stable the ecosystem

Question 47

how does making comparisons with dna help look at classification

Answer 47

dna determines proteins proteins determines features comparing dna helps determine evolutionary relationships

Question 48

what is interspecific variation

Answer 48

variation between species

Question 49

what is intraspecific variation

Answer 49

variation in a species