Topic 4 Biodiversity

Question 1

Give three ways human activity is impacting biodiversity (with examples)

Answer 1

Pollution, causes certain species of plant and animal to die which reduces biodiversity.
Overhunting, causes certain animals to be removed from the food chain which reduces biodiversity.
Urbanisation / destruction of habitats. Causes entire ecosystems to be wiped out which has a massive effect on biodiversity in the area.

Question 2

Give three reasons why humans should preserve biodiversity (with explanations)

Answer 2

For food, killing certain animals or plants would affect the entire food chain, and could damage our food sources.
For ethics, We damage biodiversity often, we should strive to not leave a negative effect on every aspect of the earth.
For aesthetics, Increased biodiversity creates a more vibrant and lush environment, which is much more pleasant to inhabit.

Question 3

Define the term species

Answer 3

A species is a group of organisms that have similar morphology, physiology and can interbreed to produce fertile offspring.

Question 4

Explain why understanding a species’ niche enables more successful conservation of that species.

Answer 4

Because it allows you to focus your efforts on preserving the species’ access to said niche, e.g. preserving honeybees by planting more flowers and not damaging beehives.

Question 5

Definition of a species niche

Answer 5

The role a species plays in an environment, and the way a species exploits its environment.

Question 6

Definition of a behavioural adaptation

Answer 6

An adaptation to a species’ actions to increase species survival, e.g a robin being territorial to prevent competition for food.

Question 7

Definition of an anatomical adaptation

Answer 7

An adaptation to an organisms anatomy to increase species survival, e.g. a fly has many eyes to allow for hypersensitive 360degree vision.

Question 8

Definition of a physiological adaptation

Answer 8

An adaptation to a species’ cell biology to increase species survival, e.g. zona pelucida hardening after a sperm cell breaches the cell membrane to prevent polyspermy.

Question 9

State the 3 domains of classification

Answer 9

Prokaryote, Eukaryote, Archaea.

Question 10

Explain what is meant by molecular phylogeny

Answer 10

Comparison of species’ DNA, mRNA and Proteins to determine how closely related they are to one another

Question 11

Explain how molecular phylogeny enables organisms to be classified and evolutionary relationships to be identified.

Answer 11

It enables organisms to be classified by how similar they are physiologically, as their Proteins can be compared, also allows evolutionary relationships such as Converging, parallel or diverging evolution to be identified as species’ DNA can be compared with their behaviour and morphology.

Question 12

What is meant by the term peer review

Answer 12

The process by which a panel of your scientific peers (People with similar qualifications in the same field) assess your work to make sure your scientific methodology is correct.

Question 13

Explain how peer review enables the validity of findings to be established

Answer 13

Peer review allows for other people’s experience and findings to help verify the validity of your own results, as others may already have experience with similar research.

Question 14

List how scientists can communicate their findings to the general public and to the scientific community.

Answer 14

To the general public: Speeches, news reports, advertisements.
To the scientific community:
Scientific journals, conferences.

Question 15

Give the 5 conditions the Hardy-Weinburg formula is dependent upon

Answer 15

• Large population
• no immigration or migration
• no mutations
• mating is random
• no natural selection

Question 16

Explain why the H-W formula cannot be used for sex-linked conditions (hint: consider the XY chromosomes)

Answer 16

Because males carry xy combination of chromosomes, they only have one allele

Question 17

Give the two formulas needed for Hardy-Weinburg calculations and provide a key

Answer 17

p^2 + 2pq + q^2 = 1.0

p + q = 1.0

p = frequency of dominant allele

q = frequency of the recessive allele

Question 18

Explain how reproductive isolation can result in speciation (the formation of new species)

Answer 18

Because the different isolated populations will have different mutations and be exposed to different selection pressures, and therefore will evolve in different ways.

Question 19

Define biodiversity

Answer 19

Biodiversity is the number and distribution of different organisms inside a community of organisms.

Question 20

Define the term endemic

Answer 20

An endemic species is a species which is only found in one habitat.

Question 21

Give the formula for heterozygosity index

Answer 21

2pq

Question 22

Explain how heterozygosity index gives a measure of biodiversity

Answer 22

It shows how varied a species’ gene pool is, which gives an indication of how diverse the species is.

Question 23

Define the term species richness

Answer 23

The number of different species in a habitat

Question 24

Define the term species evenness

Answer 24

The distribution of organisms within different species ( Higher species evenness = more evenly spread distribution of organisms)

Question 25

List the four roles of a zoo

Answer 25

Scientific research about ecology/breeding behaviour Captive breeding programmes Reintroduce animals into the wild Educate the general public

Question 26

Define the term genetic drift

Answer 26

Occurs in a small, closed population. Some alleles are not passed on through chance which leads to a reduction in the gene pool (fewer alleles in the population) which makes the population at greater risk of extinction if environment changes

Question 27

Define the term inbreeding depression

Answer 27

Occurs in small, closed populations. In small populations there are a limited number of sexually mature adults, therefore increasing the likelihood of closely related individuals breeding, which causes homozygous recessive genotypes to be passed down, which is often harmful in offspring as this genotype often carries disease.

Question 28

Explain how studbooks avoid genetic drift and inbreeding depression in captive bred populations

Answer 28

Keeps track of who is related to who, stops them from breeding together, Keeps track of where animals came from, If animals are closely related or have similar genotypes to their current captive population they are transported to other captive bred populations to increase genetic diversity.

Question 29

Explain the conditions needed in order to store seeds in seedbanks

Answer 29

Cold: reduces enzyme activity to prevent germination, prevents decat Dry: to prevent damage via ice crystal formation (freezing effect) These factors protect viability and longevity.

Question 30

Explain why seeds need to be tested for viability

Answer 30

to deduce the quality of seeds, to determine the efficacy of seed storage and to help plant the proper amount of seeds

Question 31

Give reasons why storage of seeds is useful from a conservation standpoint

Answer 31

Allows for reintroduction of endangered populations into the wild, preserves genetic diversity to prevent genetic drift in small populations,

Question 32

Compare and contrast the structure of starch with cellulose

Answer 32

Starch: made of 2 polymers, Made of alpha glucose, 1,4,6 glycosidic bonds Cellulose: Made of one polymer, H bonds between chains, Beta glucose, 1,4 glycosidic bonds Both: Polymer chains made via condensation reaction

Question 33

State the stages involved in a clinical trial and give a reason for each stage

Answer 33

Stage 1: Animal trial to test safety / toxicity of drug Stage 2: Test on small group of healthy volunteers to test for side effects Stage 3: Test on small group of diseased individuals to confirm efficacy of drug and to find correct doseage, Stage 4: Double blind trial on large group of diseased individuals to test efficacy without placebo or bias. Stage 5: Post clinical trials to find long term side effects of drug

Question 34

Compare and contrast the modern clinical trial procedure with the William Withering procedure

Answer 34

Both involve treating diseased patients with the drug to establish if it is effective at fighting the disease. Modern trial involves testing on animals first to confirm safety, william withering trial does not. Modern trial tests for placebo effect, william withering trial does not. Both involve slowly increasing dosage until side effects are seen to find correct dosage.

Question 35

Explain what is meant by a double blind trial and why it is necessary

Answer 35

A double blind trial is where both the drug takers and administers do not know which is a placebo drug and which is a real drug, and it is used to establish how much of a role the placebo effect plays in the treatment of the disease.

Question 36

Explain what is meant by placebo and why it is necessary

Answer 36

Placebo effect is a psychological reaction where the brain thinks it is receiving treatment which causes the body to stop reacting to the disease in the same way, essentially treating the disease.