biodiversity

Question 1

what is species richness

Answer 1

number of species within an ecosystem / community

Question 2

what is species diversity

Answer 2

number of different species in an ecosystem, and also the abundance across the different species present

Question 3

what is genetic diversity

Answer 3

diversity of alleles and genes in the genome of species

Question 4

how can genetic differences arise between populations of the same species

Answer 4

the two populations occupy slightly different ranges in their habitat and so are subject to slightly different selection pressures that affect the allele frequencies in their populations

Question 5

in what type of populations is genetic diversity limited

Answer 5

in populations that are very small or isolated as inbreeding is small, isolated populations leads to a high proportion of individuals being homozygous (e.g. AA to aa) for many genes, resulting in lower genetic diversity
This can mean that genetic diseases caused by recessive alleles can become more common in these populations

Question 6

what is endemism

Answer 6

species found in only one location

Question 7

how are fertilisers bad for the level of biodiversity

Answer 7

Fertilisers can leach into waterways, causing eutrophication, which can lead to the death of many aquatic invertebrate and fish species

Question 8

why are pesticides bad for the level of biodiversity

Answer 8

used on crops kill insect pests but also kill many non-target species, including important insect pollinators like bees

Question 9

how does global warming have a threat on marine biodiversity

Answer 9

Increasing atmospheric CO₂ is leading to more CO₂ dissolving in seawater, decreasing its pH (known as ocean acidification). This is negatively affecting organisms that require calcium carbonate for shells

Increased ocean temperatures have also led to an increased frequency of coral-bleaching events, where the tiny organisms that live inside corals and help keep them alive leave due to temperature stress. Without these organisms, the corals die and are broken down, eventually leading to the loss of whole coral reefs

Question 10

why can species richness be misleading indicator of diversity

Answer 10

as it does not take into account the number of individuals of each species

Question 11

what is species abundance

Answer 11

measure of the relative number of individuals in the different species within a given area

Question 12

what is random sampling used to estimate

Answer 12

The distribution of a species

The abundance of a species

Question 13

how can sampling bias be avoided

Answer 13

Quadrats must be laid randomly in the area

Question 14

what techniques are used for sampling animal species

Answer 14

Sweeping nets used to catch flying insects and insects that live in long grass by sweeping the net back and forth through the grass

Pitfall traps : cans or jars that are buried in the ground that are used to catch insects and other invertebrates as they fall into the trap

Kick-sampling catch freshwater invertebrates living in streams or rivers

Question 15

what are hetrozygotes

Answer 15

Organisms that have two different alleles at a particular gene locus

Question 16

formula for heterozygosity index

Answer 16

number of heterozygotes / number of individuals in the population

Question 17

index of diversity formula and what happens as the number obtained gets larger

Answer 17

The larger the number obtained, the higher the level of diversity

N(N-1) / {n(n-1)

N = total no. of organisms in the community
n = total no. of organisms for a single species in the community

Step 1: Calculate N(N-1) to find value A
Step 2: Calculate n(n-1) for each species and add all these numbers together to find value B
Step 3: Divide value A by value B

Question 18

what is a niche

Answer 18

The role that a species plays within its habitat

Question 19

what happens if two species try occupy same niche

Answer 19

compete with each other for the same resources
One of the species will be more successful and out-compete the other species until only one species is left and the other is either forced to occupy a new, slightly different niche or to go extinct from the habitat

Question 20

three types of features of an organism that increase their chances of surviving and reproducing

Answer 20

Anatomical, which refers to structural features

Behavioural, which refers to behaviours such as courtship of defensive behaviours

Physiological, which refers to processes inside the body, such as venom production or the ability to digest cellulose

Question 21

how can selection pressures increase chance of individuals with specific phenotypes surviving and reproducing over others

Answer 21

advantageous alleles that code for the favourable phenotype will be passed on to offspring

When selection pressures act over several generations of a species, they have an effect on the frequency of alleles in a population through natural selection

Question 22

what conditions must be met for Hardy Weinberg principle to be true

Answer 22

Mating must be random between individuals
The population is infinitely large
There is no migration, mutation or natural selection

Question 23

what is hardy weinberg principle

Answer 23

allele frequencies of a gene within a population will not change from one generation to the next

Question 24

what is the letter for
homozygous dominant
homozygous recessive

Answer 24

p2
q2

Question 25

what is reproductive isolation

Answer 25

when changes in the alleles and phenotypes of some individuals in a population prevent them from successfully breeding with other individuals in the population that don't have these changed alleles or phenotypes

Question 26

3 causes to reproductive isolation

Answer 26

Seasonal changes - some individuals in a population may develop different mating or flowering seasons to rest of population Mechanical changes - some individuals in a population may develop changes in their genitalia that prevent them from mating successfully with individuals of the opposite sex Behavioural changes - some individuals in a population may develop changes in their courtship behaviours, meaning they can no longer attract individuals of the opposite sex for mating

Question 27

how does speciation occur

Answer 27

when populations of a species become separated from each other by geographical barriers creates two populations of the same species who are geographically isolated from each other, and as a result, no gene exchange can occur between them If there are sufficient selection pressures acting to change the gene pools (and allele frequencies) within both populations then eventually these populations will diverge and form separate species The changes in the alleles/genes of each population will affect the phenotypes present in both populations Random mutations within each population will also change allele frequencies in each Over time, the two populations may begin to differ physiologically, behaviourally and anatomically

Question 28

what is each group called when grouping organisms

Answer 28

taxa

Question 29

what type of species are grouped together in the same genus

Answer 29

different species with similar genotypes and phenotypes

Question 30

why are species in the same genus seperate species

Answer 30

because they cannot produce fertile offspring This is known as the species concept

Question 31

what are the 3 domains

Answer 31

Archaea (prokaryotes) Bacteria (prokaryotes) Eukarya (eukaryotes)

Question 32

what is phylogeny

Answer 32

evolutionary history of different groups of organisms and can specify how closely related they are

Question 33

what does molecular phylogeny rely on

Answer 33

similarities or differences of molecules (such as DNA, RNA or proteins) between groups of organisms to determine how closely related they are The more similar the molecules, the more recent the common ancestor is that they share

Question 34

how do seed banks conserve plant diversity

Answer 34

drying and storing seeds in a temperature-controlled environment seeds of the same species are collected from different sites to maintain genetic diversity After a certain period of time the stored seeds are grown into plants and fresh seeds for storage are taken from those plants X-rayed to check for { viability / viable embryos

Question 35

advantage of seed bank

Answer 35

It provides an opportunity to investigate how to successfully grow plants from seeds They provide a stock of endangered plants that could be useful to humans (e.g. medicinal plant species, crop plant species) taking pressure off of wild populations

Question 36

disadvantage of seed banks

Answer 36

testing for viability is expensive and time consuming

Question 37

what are the problems with zoos

Answer 37

Captive breeding of small species populations can reduce genetic diversity ethics of keeping animals in captivity

Question 38

benefits and negatives of reintroduction

Answer 38

prevent them from going extinct in the wild Organisms that rely on these plants and animals for food or habitat may also benefit from their presence These organisms may carry new diseases that will harm other organisms living in that habitat Reintroduced animals may lack the ability to find food or communicate effectively with members of their own species

Question 39

why is the use of protected reserves more successful for conservation of animals over captive breeding

Answer 39

less stress and trauma natural interspecific relationships exist disease is less likely to wipe population animals more likely to breed in natural environment

Question 40

two differences between genetic diversity and species richness

Answer 40

idea that, GD considers one species but SR considers {different / number} species ; 2. idea that, GD considers {alleles / genotypes / eq} but SR is within a {habitat / area

Question 41

why is it better to store seeds from several individual plants of one species rather than seeds from one individual plant

Answer 41

idea of {greater / maintain} genetic variety e.g. wider gene pool, different alleles; idea of less chance of inbreeding; idea of reducing chance of storing seeds with {low viability / disease / eg} ;

Question 42

2 reasons why seeds need to be dried then stored in cold conditions

Answer 42

inhibits germination / eq; 2. idea of slowing down {enzymes / biochemical reactions}; 3. slows down rate of { decay / microbial activity / eg } ; 4. (therefore) prolongs seed survival / eq; 5. idea that drying reduces freezing effect ;

Question 43

how does inbreeding lead to genetic defects

Answer 43

closely-related mated with each other / a small gene pool / eq; * reference to inbreeding depression; * idea of increased chance of homozygous recessive genotypes for genetic defects;

Question 44

factors needed to be taken into account when zoos carry out captive breeding and reintroduction programmes for greater flamingo

Answer 44

maintenance of genetic diversity (1) by { selection of mates / use of stud books } (1) (use of stud books in order) to prevent {inbreeding depression / genetic drift } (1) habitat protected (from development) (1) relevant requirement of area into which flamingos reintroduced (1)

Question 45

what is biodiversity

Answer 45

{number / range / variety / eq} of species; 2. genetic variety within a species / number of different alleles in a {species / gene pool} ;

Question 46

Suggest advantages of selecting seeds of different sizes for long-term storage.

Answer 46

idea of maintaining or increasing {genetic diversity / size of gene pool / genetic variation} ; 2. idea of more chance of having beneficial alleles / eg: 3. increases chance of future survival {if environment changes / due to higher adaptability } / eq; 4. less chance of all being susceptible to a disease

Question 47

Describe what the seedbank will do with these seeds to ensure the long-term conservation of the species.

Answer 47

details of assessment of seed viability e.g. only select seeds with a living embryo, use of X ray (to detect embryo presence) / eq; 2. idea of {cleaning seeds / surface sterilisation / eq} ; 3. idea of drying (of the seed) ; 4. idea of storing at low temperatures; 5. idea of regularly testing viability (during storage of seed); 6. idea of what to do if viability decreases, e.g. if less than 75% germinate collect fresh seed for storage;

Question 48

describe how zoos use captive breeding and reintroduction to conserve rare species

Answer 48

to increase numbers/population size; 2. to {maintain / increase} genetic diversity/ reduce genetic drift / eq; 3. protect from {predators / poachers inter-zoo animal movement / eq; 5. selection of mates / use of stud books / records kept of breeding programme / eq; 6. process involved described e.g. IVF preparation for reintroduction described e.g. idea of reinforcing wild behaviour / idea of hacking out / reduce food intake to encourage hunting; select {habitat / reserves} ; raise {awareness / education? of local population

Question 49

what is difference between genetic diversity and species richness

Answer 49

GD considers one species but SR considers {different / number} species

Question 50

Suggest two reasons why it is better to store seeds rather than to store whole plants.

Answer 50

take {less / smaller} space / eq ; 2. can have more individuals / eq ; 3. reference to {greater / more} genetic variety ; 4. idea of less {maintenance / cost} ; 5. likely to survive longer / eq ; 6. can freeze seeds / eq

Question 51

why it is better to store seeds from several individual plants of one species rather than seeds from one individual plant.

Answer 51

idea of {greater / maintain} genetic variety e.g. wider gene pool, different alleles ; 2. idea of less chance of inbreeding ; 3. idea of reducing chance of storing seeds with {low viability / disease / eq} ;

Question 52

what effect transferring Rafa from one zoo to another had on genetic diversity in this species.

Answer 52

Increase genetic diversity allows outbreeding and mating with genetically different individuals

Question 53

Suggest why seed germination is tested at regular intervals.

Answer 53

idea that checking {seed viability / germination success / eq } ; 2. allows new seeds to be produced / eq ; 3. idea that stored seeds may need replacing e.g. due to decay / death

Question 54

Describe how breeding programmes at zoos are designed to reduce the risk of inbreeding.

Answer 54

selection of { unrelated / genetically different } mates / eq ; 2. use of stud books / records of mating / DNA profiling / eq ; 3. exchange of animals between zoos / eq ; 4. exchange of gametes between zoos / eq ; 5. IVF / AI / eq ;