Biodiversity (ARN)

Question 1

What is meant by genetic diversity?

Answer 1

The total number of different alleles in a population. A greater number of different alleles means a greater genetic diversity

Question 2

What is an allele?

Answer 2

A variant or form of a gene that occupies the same position (locus) on homologous chromosomes.

Question 3

What is a population?

Answer 3

A group of individuals of the same species that live in the same place and can interbreed.

Question 4

What is a species?

Answer 4

A group of organisms that can interbreed and produce fertile offspring.

Question 5

What is a selection pressure?

Answer 5

An environmental change that affects the chance of survival of individuals in a population

Question 6

How does genetic diversity affect a population’s resistance to selection pressures?

Answer 6

The greater the genetic diversity, the more resistant a population is to selection pressure, as the wide range of characteristics in the population means it is more likely that an individual possesses a trait that can suit new environmental conditions

Question 7

What is natural selection?

Answer 7

Process where individuals with traits better suited to their environment are more likely to survive, reproduce, and pass on those advantageous traits, leading to changes in the genetic makeup of a population over time.

Question 8

What is evolution?

Answer 8

A change in the genetic makeup of a population over time, driven by natural selection, where advantageous traits become more common due to increased survival and reproduction

Question 9

Describe the process by which a species becomes adapted to their environment

Answer 9

• Random mutations of alleles can lead to an advantageous trait that is better adapted to the environment. Individuals with this trait are more likely to survive in competition with others.
• They also have an increased chance of reproducing, so the advantageous allele is more likely to be passed on to the next generation.
• Over many generations, the number of individuals with the advantageous alleles increases at the expense of those with less advantageous alleles, as they have a greater chance of surviving and reproducing.

Question 10

Polygenetic traits are

Answer 10

Influenced by more than one gene

Question 11

Monogenetic traits are

Answer 11

Influenced by only one gene

Question 12

Directional selection favours

Answer 12

Individuals with extreme phenotypes. It moves the mean closer to the extreme that is being selected for

Question 13

Stabilising selection favours

Answer 13

Individuals closest to the mean, when environmental conditions remain stable. Phenotypes around the mean are selected for and those at the extremes are being selected against.

Question 14

Anatomical adaptations are

Answer 14

Physical features of animals that have evolved to enhance their survival.

Question 15

Physiological adaptations are

Answer 15

Internal body processes that regulate and maintain homeostasis for an organism to survive in their environment.

Question 16

Behavioural adaptations are

Answer 16

Actions that organisms exhibit to increase chances of survival.

Question 17

Artificial classification …

Answer 17

divides organisms according to observable, non-evolutionary characteristics, like colour or size, rather than evolutionary relationships

Question 18

Phylogenetic classification is based upon … (4)

Answer 18

• Evolutionary relationships between organisms and their ancestors
• Classification of species based on shared features derived from their ancestors
• Arrangement of organisms into hierarchies
• Homologous characteristics

Question 19

What is meant by a hierarchy?

Answer 19

Groups within groups that don’t overlap

Question 20

What are homologous characteristics?

Answer 20

Characteristics that have similar evolutionary origins, regardless of function.

Question 21

Taxonomic ranks

Answer 21

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 22

Features of the binomial naming system (6)

Answer 22

• Universal system based on Latin and Greek.
• The first name denotes the genus and is known as the generic name
• The second name denotes the species and is known as the specific name
• Names are printed in italics or underlined
• The first letter of the generic name is capitalised, the rest is lowercase
• If the specific name is not known, it can be written as sp.

Question 23

How do individuals recognise members of their own species?

Answer 23

By their behaviour and appearance

Question 24

Courtship behaviour helps individuals to pass on their DNA by allowing them to… (5)

Answer 24

• Recognise members of their own species
• Identify a mate that is capable of breeding because both partners need to be sexually mature, fertile and receptive to mating
• Form a pair bond that will lead to successful mating and raising of offspring
• Synchronise mating
• Become able to breed

Question 25

What is meant by species diversity?

Answer 25

The number of different species and the number of individuals within any one community

Question 25

4 components of biodiversity:

Answer 25

1. Species diversity 2. Genetic diversity 3. Ecosystem diversity 4. Species richness

Question 26

What is meant by genetic diversity?

Answer 26

Total number of different alleles in a population

Question 27

What is meant by ecosystem diversity?

Answer 27

Range of different habitats in a community

Question 28

What is meant by species richness?

Answer 28

The number of different species in a community at a given time

Question 29

What does index of diversity indicate?

Answer 29

Gives an indication of the species diversity. Greater value of index of diversity indicates a greater species diversity

Question 30

Index of diversity equation

Answer 30

D = (N(N-1))/(Σn(n-1))

Question 31

What to the letters stand for in the index of diversity equation?

Answer 31

d = index of diversity N = total number of organisms of all species n = total number of organisms of each species

Question 32

Why do agricultural ecosystems have a low biodiversity?

Answer 32

Because farmers select for desirable qualities and grow a large amount of these crops for commercial gain.

Question 33

Why does growing a large amount of desirable crops reduce biodiversity?

Answer 33

It leaves very little space for other species which will have to compete for the very little space available to them. Many individuals will not survive this competition, reducing the population of undesirable species.

Question 34

Practices that have reduced biodiversity

Answer 34

- Removal of hedgerows. - Grubbing out woodland - Pesticides and inorganic fertilisers - Overgrazing of land which prevents regeneration of woodland - Draining ponds

Question 35

How has removal of hedgerows reduced biodiversity?

Answer 35

Reduces habitat availability and isolates populations. Hedgerows connect habitats allowing species to move between them. Removing them isolates species, leading to more inbreeding and reduces genetic diversity.

Question 36

How has grubbing out woodland reduced biodiversity?

Answer 36

Reduces habitats and food sources

Question 37

How does draining ponds reduce biodiversity?

Answer 37

Removes habitats and reduces water availability for plants

Question 38

Biodiversity conservation techniques

Answer 38

- Plant hedges rather than use fences - Maintain existing ponds and create new ones - Leave wet corners of fields rather than draining them - Plant native trees on land with a low species diversity - Organic fertilisers

Question 39

How we measure genetic diversity in a species?

Answer 39

Sampling DNA of its members and sequencing it to create coloured bands, with each base having a different colour. Analysis and comparison of these patterns allows us to determine diversity in a species.

Question 40

Why might a sample not be representative of a population?

Answer 40

1. Sampling bias – people may not want to take a sample in a muddy area 2. Chance – It could happen that the flowers that you sampled are the tallest flowers in the area

Question 41

Ways to reduce sampling bias

Answer 41

- Divide the study area into a numbered grid - Use a random number generator to generate a coordinate - Take samples at this coordinate

Question 42

Ways to reduce the effect of chance

Answer 42

- Use a large sample size, which reduces the influence of anomalies - Analyse data using statistical tests

Question 43

What is meant by standard deviation?

Answer 43

It is a measure of the spread of data around the mean value. It gives a better idea of the range of values.