4.2.1 Biodiversity

Question 1

What is biodiversity?

Answer 1

Biodiversity refers to the variety of organisms in an area.

Question 2

Describe the three levels of biodiversity.

Answer 2

Habitat diversity - number of habitats

Species diversity - number of species and number of individuals in each species

Genetic diversity - variation in alleles within a population of a species

Question 3

Why is high genetic biodiversity important?

Answer 3

Allows for better adaptation to a changing environment and resistance to disease.

Question 4

Define the term species.

Answer 4

A group of organisms that can interbreed to produce fertile offspring

Question 5

Define the term habitat.

Answer 5

The place where a species lives within an ecosystem.

Question 6

What is species richness?

Answer 6

The total number of different species in a habitat.
Measured by taking random samples and counting the different species present.
Higher species richness = greater diversity

Question 7

What is species evenness?

Answer 7

A comparison of the numbers of individuals of each species in a community.
Measured by taking samples and counting individuals of each species.
More even abundance = higher species richness & diversity

Question 8

Why is random sampling important in biology?

Answer 8

It avoids bias and ensures the sample is representative of the whole population.

Question 9

Outline the basic steps of random sampling.

Answer 9

1. Choose an area
2. Randomly generate coordinates across the area - prevents sampling bias by removing human involvement.
3. Collect samples from random coordinates - samples that are representative.
4. Repeat several times - large sample size and minimises effects of chance.
5. Analyse data collected - identify relationships.

Question 10

What are techniques used to sample animals?

Answer 10

Pooters - samples small insects by sucking them into a container via a tube
Sweep nets - samples insects in long grass or air using a figure-of-eight motion.
Pitfall traps - samples small, ground-crawling animals by catching them in a trap.

Question 11

What is a quadrat used for?

Answer 11

To sample plants and non-motile animals in an area.

Question 12

Describe the two types of quadrats.

Answer 12

Frame quadrat - square frame divided into a grid used to record species in each section.
Point quadrat - frame with a horizontal bar through which pins are dropped at intervals, species touched by pins are recorded.

Question 13

What is species frequency in a quadrat?

Answer 13

Number of squares in a quadrat a species is found in divided by number of total squares in the quadrat x100

Question 14

What is percentage cover in a quadrat?

Answer 14

An estimate of the area within a quadrat that a species covers.

Question 15

What is the key difference between random and non-random sampling?

Answer 15

• Random sampling removes human bias by selecting samples randomly, improving reliability
• Non-random sampling uses specific criteria and is prone to bias.

Question 16

Name three types of non-random sampling.

Answer 16

Opportunistic
Stratified
Systematic

Question 17

What is opportunistic sampling?

Answer 17

Type of non-random sampling
The most conveniently available organisms are sampled.
It may not be representative.

Question 18

What is stratified sampling?

Answer 18

The population is divided into zones (strata) based on a characteristic, and random samples are taken from each group in proportion to its size.

Question 19

What is systematic sampling?

Answer 19

Sampling at regular intervals along an area to assess changes in species distribution.
Often used with transects.

Question 20

What is transect sampling used for?

Answer 20

Method for studying the distribution of organisms in a specific area.
Typically used in systematic sampling.

Question 21

How is a line transect used?

Answer 21

A line is marked & species are sampled at regular intervals along it.

Question 22

How is a belt transect used?

Answer 22

Samples are taken in an area along a lines or between two parallel lines, by using a quadrat.

Question 23

What abiotic factors can be measured in the field?

Answer 23

• Light, humidity, temperature (using sensors)
• pH, wind speed (using probes)
• Dissolved oxygen (using specialised probes)

Question 24

Why should abiotic factors be measured when sampling?

Answer 24

• Detect rapid changes
• Reduce human error
• Increase precision
• Allow digital data storage and tracking

Question 25

How could you investigate the effect of pH on vegetation along a shore?

Answer 25

1. Place a transect perpendicular to the shore 2. Sample at regular intervals using quadrats 3. Record % cover of target species 4. Measure pH at each interval 5. Plot a graph of the data and analyse relationships

Question 26

What does **Simpson’s Diversity Index** measure?

Answer 26

It measures **biodiversity** by considering **species richness** (number of species) and **species evenness** (relative abundance).

Question 27

What is the formula for Simpson’s Diversity Index?

Answer 27

given in exam n = number of individuals of one species N = total number of individuals of all species

Question 28

What does a higher value of 𝐷 indicate?

Answer 28

𝐷 ranges from 0 to 1, with 1 = maximum diversity A higher 𝐷 means greater biodiversity, with species being more evenly distributed.

Question 29

What is **genetic** biodiversity?

Answer 29

It refers to the **variety of alleles** (gene variants) in a population's gene pool.

Question 30

Why is high genetic biodiversity important?

Answer 30

Increases a polulation's ability to adapt to environmental changes So helps them avoid extinction.

Question 31

What is a **polymorphic** gene locus?

Answer 31

A polymorphic gene locus has more than one allele Meaning there’s variation in the population. (Example: The gene for blood type is polymorphic because there are A, B, and O alleles.)

Question 32

What is a **monomorphic** gene locus?

Answer 32

A locus with only one allele, keeping the species' traits consistent.

Question 33

How do you calculate the proportion of polymorphic gene loci?

Answer 33

Proportion = no. of polymorphic loci divided by total no. of loci

Question 34

How can genetic diversity **increase** in a population?

Answer 34

* **Gene flow** - interbreeding between different populations, introducing new alleles * **Mutations** in DNA of organisms - creates new alleles

Question 35

How can genetic diversity **decrease** in a population?

Answer 35

* Selective breeding * Captive breeding programmes * Artificial cloning * Natural selection * **Genetic bottlenecks** - sudden decrease in population size, only few individuals remain * The **founder effect** - few individuals from original population split to form a new population. * **Genetic drift** - alleles are randomly passed down and some may disappear by chance.

Question 36

How does human population growth affect biodiversity?

Answer 36

* **Deforestation** destroys habitats and reduces ecosystem biodiversity. * **Overuse of resources** causes certain species to decline or go extinct, reducing **genetic & species diversity** * **Urban sprawl** isolates wildlife populations, limiting breeding and **decreasing genetic diversity** * **Pollution** kills species directly and harms habitats long term.

Question 37

What are some farming methods that reduce biodiversity?

Answer 37

* **Monocultures** - decrease diversity of plants & deplete nutrients from soild * Converting woodland and hedgerows into **fields** - destroys habitats & reduces species * **Filling in ponds**, **draining marshes** & **over-grazing** * Removing weeds with **herbicides** * Using **pesticides** to kill crop pests - harm unintented species or those that depend * Using **inorganic fertilisers** - may runoff into water courses, damaging aquatic species

Question 38

Name 3 ways farmers can support biodiversity while farming.

Answer 38

* Maintain hedgerows * Reduce pesticide and herbicide use * Use organic fertilisers * Using crop rotation

Question 39

What is the effect of climate change on biodiversity?

Answer 39

* Climate change alters temperature and rainfall, affecting species' habitats. * Some habitats may **shrink** (e.g. melting ice caps), changing species distribution and migration. * Slow-moving species may go **extinct**. * Warmer climates may spread **tropical diseases**. * Rising sea levels can flood low-lying habitats.

Question 40

What are the three reasons for **conserving** biodiversity?

Answer 40

Ecological, economic & aesthetic

Question 41

What are the **ecological reasons** for conserving biodiversity?

Answer 41

* Maintains stable **food webs** and prevents disruption of food chains. * Protects **keystone species** which have large ecosystem impacts. * Supports **nutrient cycles** via decomposers (e.g. carbon, nitrogen). * Increases ecosystem **resilience** to climate change, stress, and disease.

Question 42

What are the **economic** benefits of conserving biodiversity?

Answer 42

* Provides resources: timber, fabric, **biofuels**, **medicines**, pesticides. * Supports **ecotourism**, generating national income. * Microorganisms contribute to biotechnology and **antibiotic** production. * Protects genetic diversity for future products and climate resilience.

Question 43

How does biodiversity benefit **agriculture**?

Answer 43

* Prevents **monoculture problems** like low yields and soil depletion. * Wild crop relatives offer genes for breeding better varieties. * Genetic diversity protects crops from **disease** and **pests**. * Many crops rely on insect **pollinators** to reproduce.

Question 44

What are the **aesthetic reasons** for biodiversity conservation?

Answer 44

* Biodiversity **enriches** environments, offering natural beauty. * Helps people recover from stress and illness through nature

Question 45

What is ***in situ*** conservation and how is it carried out?

Answer 45

*in situ* conservation protects species **within their natural habitat**. Methods include: * National parks and wildlife reserves * Marine conservation zones * Controlling invasive species * Protecting food sources and nesting sites * Banning hunting of endangered species

Question 46

What are the advantages of ***in situ*** conservation?

Answer 46

* Larger populations can be sustained * More chance of recovery than *ex situ* conservation * Less disruption to ecosystems * Natural behaviour and interactions are preserved

Question 47

What is ***ex situ*** conservation and how is it done?

Answer 47

Ex situ conservation involves protecting species **outside their natural habitat**. Methods include: * Relocation to safer areas * **Captive breeding** in zoos or botanical gardens * Seed banks

Question 48

What are the limitations of *ex situ* conservation?

Answer 48

* Captive animals may **lose disease resistance** * **Behavioural problems** may develop * **Genetic differences** from wild populations

Question 49

Name three conservation agreements.

Answer 49

CITES Rio Convention on Biological Diversity (CBD) Countryside Stewardship Scheme (CSS)

Question 50

What does the Rio Convention on Biological Diversity (CBD) aim to do?

Answer 50

* Develop **global conservation** strategies and promote **sustainable** use of resources. * Make conservation an international legal responsibilty * Address climate change and land degradation * Provide government guidance on protecting habitats

Question 51

What does **CITES** do?

Answer 51

* Makes the trade of endangered species **internationally illegal**. * Regulates trade of wildlife and their products (e.g. ivory, skins) * Requires permits for legal trade * **Raises awareness** through education on threats

Question 52

What does the Countryside Stewardship Scheme (CSS) do?

Answer 52

Pays farmers to manage land **sustainably** Actions include: * Leaving field margins * Protecting hedgerows * Controlling grazing Enhances **local biodiversity** and integrates conservation into agriculture