4.2.1 Biodiversity

Question 1

Define biodiversity

Answer 1

measure of variation found in the living world

Question 2

Define habitat biodiversity

Answer 2

range of habitats in which diff species live (sand dunes, woodland, meadow, streams)

Question 3

Define species biodiversity

Answer 3

range of organisms found in a habitat (species richness and evenness)

Question 4

What is species richness and species evenness?

Answer 4

richness: no. of species
evenness: no. of individuals in each species/the degree to which theyre represented.

Question 5

Define genetic biodiversity

Answer 5

variation between individuals belonging to the same species -> breeds / number of different alleles in a population

Question 6

Why is sampling important?

Answer 6

Impossible to count all fungi, bacteria and other single-celled organisms for example. So must SAMPLE -> select a small portion and then scale up

Question 7

What is random sampling? State its advantages and disadvantages

Answer 7

randomly generating numbers as coordinates, or from a map

• ensures data aren’t biased

-low presence species might be missed = underestimate
- might not cover all areas equally

Question 8

What is opportunistic sampling? State its advantages and disadvantages

Answer 8

• decisions based on prior knowledge - deliberate due to containing a species
• easier and quicker

-may be biased
-may be an overestimate due to large and colourful species

Question 9

What is stratified sampling? State its advantages and disadvantages

Answer 9

• dividing a habitat into diff areas and sampling each separately
• ensures species aren’t under-represented and that all areas are sampled
• may lead to over-representation

Question 10

What is systematic sampling? State its advantages and disadvantages

Answer 10

• samples taken at fixed intervals using line and belt transects
• useful when habitat shows a clear change in an environmental factor
• species may be missed if not on line = underestimate

Question 11

Explain how you use a quadrat

Answer 11

used to define size of sample area

generate random numbers as coords and place it there. Identify plants found.

estimation: some have grid which make them more accurate since percentage cover can be estimated
point frame: no. of long needles, lower it into quadrat and record any plants touching. best to use it at regular intervals. use no.of readings etc to calculate a %.

Question 12

Explain how to use a transect. What is an interrupted vs continuous belt transect?

Answer 12

• line taken across habitat, especially large ones
• can be line (just tape) or belt (with quadrats)

interrupted: at intervals
continuous: move quadrat along the line to study in detail - no gaps

Question 13

Why is it hard to sample animals by observation?

Answer 13

animals hide and often move too quickly

Question 14

What is involved in careful observation?

Answer 14

footprints, DNA sequencing of droppings, burrows, damage to trees -> can estimate population sizes

Question 15

What is capture recapture?

Answer 15

LONGWORTH TRAP
1. Capture a sample and mark each individual (C1)
2. Release them and leave traps for a period of time
3. Number captured on 2nd occasion = C2
4. Number of already marked that are captured = C3

TOTAL POPULATION = C1 x C2 / C3

Question 16

Why is capture and recapture sometimes inaccurate?

Answer 16

some know it contains food, some know it’s harmless, or some might stay away

Question 17

How are birds and larger mammals kept track of?

Answer 17

birds: ringing
larger mammals tagged

Question 18

What is Simpsons index of diversity? What does a high and low value indicate?

Answer 18

measure of diversity of a habitat -> takes into account species richness and evenness

high: diverse. tends to be stable and able to withstand environmental changes
low: habitat dominated by a few species, less stable

Question 19

How do you calculate genetic diversity in small, isolated populations?

Answer 19

• Genetic diversity is found when there is more than one allele for a particular locus (position of a gene on a chromosome)
• Genetic diversity = proportion of polymorphic gene loci (more than 2 allele) = no.of polymophic loci / total no. of loci

Question 20

Explain how human population growth affects biodiversity

Answer 20

alter ecosystems to get food, clearing land for agriculture or building, deforestation, pollution, using more resources , destroy and fragment habitats

leads to EXTINCTION - no more living members of a species. many believe we are at start of mass extinction

Question 21

Explain how agriculture affects biodiversity

Answer 21

• clear vegetation = decreases habitat size and reduces genetic diversity
• reliance on monoculture -> one strain of species -> and selective breeding = decreasing genetic diversity

selecting for specific breeds means others may die out = genetic erosion

Question 22

What is genetic erosion?

Answer 22

limited gene pool of an endangered species diminishes even more

Question 23

Explain how climate change affects biodiversity

Answer 23

• species less able to adapt as climate changes
• extreme weather causes habitat destruction
• barriers to migration (agricultural land, mountain ranges, water)
• domesticated plants and animals very at risk due to little variation -> less food available

Question 24

Explain the ecological reasons to maintain biodiversity

Answer 24

1. Interdependence: due to food chains, an effect on one species will affect other species.
2. Keystone species: disproportionate effect upon its environment relative to its abundance, many species rely on them e.g. predators that limit herbivores, plants, beavers (dams causes water flooding where species can live, water slows = good for aquatic; felled trees allow light to reach ground)
3. Maintaining genetic resource: may be able to breed new crop varieties that can cope with climate change, and use plants and microorganisms for new medicines ; huge potential in wide range of extant species

Question 25

Explain the economic reasons to maintain biodiversity

Answer 25

Food production:

Reducing soil depletion due to stopping monocultures = allows fertility and yields to increase

Biodiversity contributes to water purification, timber growth, recycling of nutrients, crop pollination, etc that food production relies on

Question 26

Explain the aesthetic reasons to maintain biodiversity

Answer 26

• physical and emotional health
• forests protect soils from erosion, trees take up water
• protecting landscape for beautiful environments, e.g. by stopping soil exposure and severe flooding caused by deforestation

Question 27

What is conservation in situ?

Answer 27

management to maintain biodiversity in the natural environment

Question 28

What are wildlife reserves? What is the conflict?

Answer 28

• designated areas established for conservation of habitats and species
• animals raiding crops, poaching, tourists feeding/ littering

Question 29

What are marine conservation zones?

Answer 29

Conserve biodiversity of nationally rare, endangered and representative habitats in our seas

Question 30

What are other in situ methods?

Answer 30

National Parks (protected UK countryside), national nature reserves (protect sensitive features of environment) and local ones, SSSI’s (country’s best wildlife)

Question 31

What is repopulation?

Answer 31

Reintroducing a species once their habitat is suitable

Question 32

What are the advantages of in situ? (4)

Answer 32

Conservation in natural environment
Protect significant elements of natural and cultural heritage
Provide opportunities for sustainable land usage
Facilitates scientific research

Question 33

What are the disadvantages of in situ? (4)

Answer 33

Habitats may become fragmented
Genetic diversity may be lost already
Harmful conditions might be present still
Might attract poachers and ecotourists who cause disturbance

Question 34

What is conservation ex-situ?

Answer 34

management outside normal habitat of species

Question 35

What takes place in zoos?

Answer 35

Captive breeding -> breeding endangered species and conducting research

Artificial insemination, in vitro fertilisation and embryo transfer with wild animals

Some carry out research on domestic species SIMILAR to target ones to avoid experimental research on endangered species

Question 36

What are the advantages of zoos? (6)

Answer 36

protected from predation and poaching
genetic diversity can be measured
increased success of breeding due to reproductive tech
research made easier
education
attractions to raise funds

Question 37

disadvantages of zoos? (5)

Answer 37

limited genetic diversity
exposed to diseases
abnormal behaviour
correct environmental conditions might be hard to achieve
difficulties when reintroducing to the wild

Question 38

What are botanic gardens for?

Answer 38

Dormant plants = seeds.
Large numbers collected from wild, stored and germinated in protected surroundings
Huge numbers in little space
Often bred asexually
Individuals can be replanted in the wild

Question 39

What are the problems with botanic gardens? (4)

Answer 39

Difficult to fund
Samples may not have representative levels of genetic diversity
Seeds may not be viable
Decreases genetic diversity due to asexual breeding

Question 40

What are seed banks for? How are seeds stored?

Answer 40

Seeds that remain viable for decades. Provide them for crops, building materials and disease-resistant crops for agriculture. repopulation of endangered species + habitat reclamation

Storage: very dry and freezing conditions as they’re resistant to desiccation. tested at regular intervals to check their viability

Question 41

What are the aims of CITES?

Answer 41

Convention on International Trade of Endangered Species of Wild Fauna and Flora = international

Overall: Ensure international trade of specimens does not threaten their survival in the wild

• ensure trade in wild plants for commercial purposes is inhibited
• restrict trade of endangered species

Question 42

What are the aims of the Rio Convention on Biological Diversity?

Answer 42

• International
• promoting sustainable development
• conservation of diversity
• sustainable use of its components
  -appropriate shared access to genetic resources
• appropriate sharing of knowledge and tech

states partner states must adopt ex situ facilities to complement in situ measures

Question 43

What were the aims of the Countryside Stewardship Scheme? What is it called now and what are its current aims?

Answer 43

• improve natural beauty of countryside, restore targeted landscapes, and improve public access. all at a local level
• Environmental Stewardship Scheme
• provides funding to farmers in England to deliver effective environmental management on their land
• help land managers to conserve and promote countryside by looking after wildlife, protecting natural resources, providing opportunities for learning

Question 44

What’s sweep netting

Answer 44

Sweep netting: through vegetation, (suitable for low, can be used in water) empty onto white sheet. A POOTER uses straw to ensure insects dont fly away

Question 45

Describe pitfall traps

Answer 45

Pitfall traps: in soil. any animals in plants/leaf litter will fall into container. Add water/scrunched paper to avoid them climbing up. Must be sheltered

Question 46

Describe tullgren funnels

Answer 46

Tullgren funnel: light above drives animals downwards as it warms up -> fall through mesh and collected

Question 47

Describe light traps

Answer 47

light trap: flying insects at night e.g. moths attracted to it and fall into collecting vessel with alcohol underneath

Question 48

The Madidi National Park, in the South American rainforest, is home to a wide variety of species.
The largest predator in the area is the jaguar. These large cats are well camouflaged and hunt
mostly at night. A single individual can cover a very large area.

(a) In 2007 the Wildlife Conservation Society (WCS) attempted to estimate the population of
jaguars in the Madidi National Park.
* Digital camera traps were placed in areas that jaguars were likely to visit.
* If an infrared beam was broken by an animal, the camera was activated.
* The camera then took a photograph of the animal.

(i) Suggest why it was not appropriate to estimate the number of jaguars using the
capture-recapture technique. (2)

Answer 48

estimate will be inaccurate (because of low numbers) 
dangerous (for collector or jaguar) 

Question 49

Most studies estimate the population density of jaguars in the South American rainforest
to be 5 individuals per 100km2.
In the 2007 study:
* 100 camera traps were set up covering an area of 271km2.
* 28 images of 9 different jaguars were recorded.
How well do these results support a population estimate of 5 individuals per 100km2? (4)

Answer 49

appropriate calculation of , observed / expected , population density 
lower than estimate 
so does not support 
low / unknown , repeatability / reproducibility 
(some) support because , figure / 3 , is close to estimate / 5 
some individuals not photographed 
idea that if many individuals not trapped population could be higher than estimate 