4.1.2 Biodiversity

Question 1

What is biodiversity?

Answer 1

variety of living organisms in an area i.e plants, animals, fungi etc

Question 2

Why is biodiversity important?

Answer 2

-maintains a balanced ecosystem which minimises impact if an individual is affected
-species can be interdependent
-humans rely on high biodiversity for medicine, food, clothes etc

Question 3

What is a community?

Answer 3

the populations of living organisms in a habitat

Question 4

How does maintaining biodiversity impact conservation?

Answer 4

-informs scientists of the species present in a habitat to provide baseline for biodiversity
-effect of any changes in the environment

Question 5

Habitat biodiversity

Answer 5

-the number of different habitats found within an area
-can support a wide variety of species, so leads to higher species biodiversity
-abiotic factors= soil, temp range
-biotic factors= availability of food, presence of predators

Question 6

Species biodiversity

Answer 6

-group of similar organisms able to reproduce to give fertile offspring
-i.e woodland= relatively large number of each species with no species dominating
-i.e farmland= large population of a small no. of species

Question 7

Species richness

Answer 7

-the number of different species present in a particular area
-measured by taking random samples of a habitat and counting the number of different species

Question 8

Species evenness

Answer 8

-comparison of the abundance of each species living in a community
-measured by taking random samples of a habitat and counting the number of individuals of each species

Question 9

What is Simpson’s Index of Diversity and how is it calcuated?

Answer 9

-used to measure species diversity
- n= total number of organisms in one species
- N= total number of all organisms
- ∑ = Sum of
-always a value between 0 and 1 (closer to 1= higher species richness & evenness, so more diverse and can adapt to environmental changes)

Question 10

Genetic biodiversity

Answer 10

-refers to the variety of genes/alleles that make up a species
-code for wide variation in characteristics seen between species–> better adaptation to a changing environment + more likely to result in resistance to pathogens

Question 11

3 ways that genetic biodiversity can be assessed

Answer 11

-the proportion of polymorphic gene loci
-the proportion of the population that is heterozygous for any specific gene loci
-allele richness(number of different alleles that exist for specific genes)

Question 12

What is the difference between polymorphic and monomorphic genes?

Answer 12

-polymorphic genes have two or more alleles whereas monomorphic have one allele for each gene–} most genes are monomorphic
-M leads to lower genetic biodiversity as there is a smaller number of alleles present + no new alleles introduced

Question 13

How to calculate genetic biodiversity

Answer 13

proportion of polymorphic gene loci= number of polymorphic gene loci/total number of loci

Question 14

Why is genetic biodiversity important?

Answer 14

-high genetic biodiversity(wide range of alleles present in the population) are more likely to adapt to environmental changes + less likely to be extinct
-due to having an advantageous allele which enables them to survive in altered conditions

Question 15

Factors that increase genetic biodiversity: mutations

Answer 15

-random + spontaneous mutations in the DNA of an organism, creating a new allele
BUT mutations don’t have an impact because they are degenerate or introns that are spliced

Question 16

Factors that increase genetic biodiversity:
interbreeding between different populations

Answer 16

-when an individual migrates from one population and breeds with a member of another population, alleles are transferred–} gene flow

Question 17

Factors that decrease genetic biodiversity:
selective breeding

Answer 17

-only a few individuals within a population are selected for their advantageous characteristic and bred i.e pedigree animals/food crops
-less desired alleles disappear from population

Question 18

Factors that decrease genetic biodiversity:
captive breeding programmes

Answer 18

-small number of captive individuals of a species are available for breeding
-i.e zoos, conservation centres (normally for endangered/extinct species)
-re-population within limited population reduces the gene pool

Question 19

Factors that decrease genetic biodiversity:
rare breeds

Answer 19

-normally the result of selective breeding
-small gene pool causes problems when trying to restore numbers but maintain certain characteristics

Question 20

Factors that decrease genetic biodiversity:
artificial cloning

Answer 20

-asexual reproduction
-using cuttings from a a plant to clone a farmed plant

Question 21

Factors that decrease genetic biodiversity:
natural selection

Answer 21

-individuals with advantageous alleles are more likely to survive + reproduce to pass them on–} less advantageous alleles become less common

Question 22

Factors that decrease genetic biodiversity:
genetic bottlenecks

Answer 22

-an event that severely reduces the gene pool because few individuals survive and can pass on alleles i.e forest fires

Question 23

Factors that decrease genetic biodiversity:
the founder effect

Answer 23

-small number of individuals create a new colony that is geographically isolated from the original
-small gene pool

Question 24

Factors that decrease genetic biodiversity:
genetic drift

Answer 24

-random nature of alleles being passed on from parents to their offspring–} allele frequency will vary and sometimes disappear
-normally in populations with a low genetic biodiversity

Question 25

Features of a habitat with LOW biodiversity

Answer 25

-relatively few successful species -stressful/extreme environment with relatively few ecological niches -species have very specific adaptations for the environment -simpler food webs -change to environment has a major effect on the ecosystem

Question 26

features of a habitat with HIGH biodiversity

Answer 26

-large number of successful species -less stressful with more ecological niches -many species in the habitat with fewer specific adaptations -complex food webs -change to environment has a relatively small effect

Question 27

What is sampling and why is it used?

Answer 27

-taking measurements of a select number of individual organisms in a particular area -can estimate the total number of organisms -can measure a particular characteristic of an organism i.e crop height

Question 28

Random sampling

Answer 28

-selecting individuals by chance--} an equal likelihood of selection -i.e divide the field into a grid using 2 measuring tapes laid at right angles, use random numbers to determine coordinates(reduces sampling bias) and take a sample at each of the coordinate pairs generated(representative samples) -Repeating my word gives a large Sample size and minimises the effects of chance -can use species identification key -count number of organisms and record this -if species is over 50% outside, it is not counted

Question 29

Non-random sampling

Answer 29

-sample is not chosen at random--} useful when there's lots of variety in the distribution of species in the habitat

Question 30

Opportunistic sampling

Answer 30

-samples are chosen by investigator (normally when organisms are not readily available) *less representative of the population + data will be biased*

Question 31

Stratified sampling

Answer 31

-populations are divided into subgroups(strata) before sampling -based on a particular characteristic i.e males + females -random sample is then taken from each strata proportional to its size *more representative*

Question 32

Systematic sampling

Answer 32

-samples are taken at fixed intervals across different areas in a habitat -**line transect**= marking a line on the ground between 2 poles and taking samples at specified points(can measure organisms that touch the line/distances of samples from the line) -**belt transect**= 2 parallel lines across the habitat--} samples are taken of the area between the two lines

Question 33

What is sampling bias + chance?

Answer 33

-sampling bias= process of selecting a sample may be bias, reduced using random sampling due to no human involvement in choosing -chance= organisms selected may not be representative of the whole population, reduced by using a larger sample size--} lower probability that chance will impact results

Question 34

Sampling animals: Pooter

Answer 34

-device used to catch small insects by sucking on a mouth piece to draw them into a holding chamber -filter before the mouth piece prevents them from being ingested

Question 35

Sampling animals: Sweep nets

Answer 35

-used to catch insects in areas of long grass -stand still and sweep the net left to right through the grass and quickly sweep up the net and pour contents into collecting tray to count

Question 36

Sampling animals: Pitfall traps

Answer 36

-used to catch small, crawling animals -hole where they fall into, covered with a roof structure so it doesn't fill with water, stone to raise lid

Question 37

Sampling animals: Tullgreen funnel

Answer 37

-for small organisms that live in soil/leaf litter -sample of this is put on a mesh filter at the top of a funnel and a light shone down onto it -light acts a heat source and dries out the soil/leaf litter, so organisms moves away from it and fall into the beaker -mesh holds the soil/leaf litter in place but lets the small organisms pass through

Question 38

Sampling animals: Kick sampling

Answer 38

-used to study the organisms living in a river -river bed is 'kicked' for a period of time to disturb the substrate -net is held just downstream for a set period of time in order to capture any organisms released into the flowing water

Question 39

Sampling plants: point quadrat

Answer 39

-frame containing a horizontal bar -at set intervals, long pins can be pushed through the bar and each species of plant the pin touched is recorded

Question 40

Sampling animals: Frame quadrat

Answer 40

-type and number of species within each section of the quadrat is recorded -used with random sampling to collect a representative sample counted by: - density= count individual large plants

Question 41

Human population growth

Answer 41

-grown at a dramatic rate in the past centuries and is continuing to grow -linked to improvements in medicine, hygiene, housing + infrastructure--} increase life expectancy

Question 42

Impacts of human population growth: deforestation

Answer 42

-provides wood for building and fuel(logging) and more space for infrastructure, housing and agriculture (land clearing) -decreases habitat diversity--} impacts species diversity due to habitat loss -may increase biodiversity of neighbouring areas as animals are forced to migrate

Question 43

Impacts of human population growth: Urbanisation

Answer 43

Cities and major road developments mean that species can become isolated and populations cannot interbreed--} lower species diversity

Question 44

Impacts of human population growth: Over-exploitation

Answer 44

-greater demand for resources i.e food, water, energy, so resources are being used up faster than replenished--} destroy habitats + directly affect species -i.e industrial fishing can deplete certain fish species, reducing genetic diversity

Question 45

Impacts of human population growth: Pollution

Answer 45

-human population is producing more waste and higher pollution rates--} kill species + decrease biodiversity i.e acid rain= lowers pH for aquatic organisms

Question 46

Impacts of agriculture: land clearing

Answer 46

-increase the land available for growing crops/rearing animals -i.e removal of hedgerows= allows farmers to use large machinery for harvesting crops + more land for growing crops--} reduces plant species diversity and destroys the habitat of many animals

Question 47

Impacts of agriculture: use of pesticides and herbicides

Answer 47

-reduces species diversity of naturally occurring plants + animals seen as pests/weeds* and may destroy food source of other organisms *weeds compete with the cultivated plants for lights, minerals, and water

Question 48

Impacts of agriculture: monoculture

Answer 48

-many farms specialise in producing a single variety of one crop i.e palm oil plantations in Africa -no wild crop varieties due to less economic benefit--} reduces species diversity AND genetic diversity(crop cannot adapt to any environmental changes + evolve due to no new alleles introduced) -increase vulnerability to pathogens and increase dependence on expensive pest/herbicides + fertilisers

Question 49

Climate change

Answer 49

-significant long-term change in an area's climate -naturally occurring but worsened by increasing CO2 levels in the atmosphere

Question 50

Impacts of climate change: Polar ice caps melting

Answer 50

-could lead to extinction of species in those regions -loss of habitat would lead to forced migration of species to find suitable conditions

Question 51

Impacts of climate change: Rising sea levels

Answer 51

-result of polar ice caps melting and thermal expansion of oceans -saltwater would fill up freshwater rivers, reducing habitats of aquatic organisims/species living around it -flood +destroy coastal habitats

Question 52

Impacts of climate change: less rainfall

Answer 52

-drought-resistant species would dominate over non-drought resistant--} loss of these plants would lead to loss of animal species that rely on them as food source -animal species that feed on xerophytes would dominate

Question 53

Impacts of climate change: life cycles impacted by adaptations

Answer 53

-if the range of insects that are pollinators i.e bees changes, it could cause extinction of the plants that rely on pollination + lower plant species distribution

Question 54

Reasons for maintaining biodiversity: Aesthetic reasons

Answer 54

-provides pleasant landscapes for leisure use i.e walk in local woodland/visit a rainforest -nature provides inspiration for musicians + writers -natural environment reduces stress and helps recover from injuries

Question 55

Reasons for maintaining biodiversity: economic reasons

Answer 55

-prevent economic dependence on other nations due to soil erosion + desertification -wide variety of species that can be chemically/medically useful i.e plants with chemical-based defence mechanisms may be potential sources of medicine -prevents monoculture causing soil depletion(less diversity in soil nutrients) -protection against abiotic stresses i.e extreme weather/disease -eco-tourism i.e coral reefs -can crossbreed with wild plant varieties to increase yield + help adaptations

Question 56

Reasons for maintaining biodiversity: Ecological reasons

Answer 56

-maintains interdependence--} i.e decomposers break down dead plant and animal remains + recycle nutrients, plants rely on pollinators(bees) which would pollinate crop and increase yields -keystone species(key role in maintaining the structure of an ecological community)= disproportionately large effect on their environment relative to their abundance i.e beavers who build dams --} help determine the species richness + evenness in the community

Question 57

What is conservation?

Answer 57

-maintenance of biodiversity through human action -increases chancels of survival + reproduction

Question 58

What is sustainable development?

Answer 58

-economic development that meets the needs of people today, without compromising the needs of future generations

Question 59

In-situ conservation

Answer 59

-within the natural habitat -maintains genetic diversity, allows species continue to adapt to changing environment + preserves interdependent relationships between species, both species and habitat are conserved BUT may be expensive and hard to manage i.e poaching, climate change

Question 60

Wildlife reserves

Answer 60

-controlled grazing -restricting human access -controlling poaching i.e issuing fines -reintroduction of species i.e to areas that have become locally extinct -culling of invasive species= not native and has negative effects on economy, environment or health -halting succession= i.e land developing into woodland--} allows for higher biodiversity + more species richness

Question 61

Marine conservation zones

Answer 61

-preserve species-rich areas i.e coral reefs -create areas where populations can build up and repopulate nearby areas

Question 62

Ex situ conservation

Answer 62

-involves the removal of an organisms from their natural habitat -can be used to protect individual animals in a controlled environment--} can manage predators + hunters -competition for resources reduced + breeding can be manipulated i.e IVF + hormones BUT only a small number of individuals can be cared for, can be difficult and expensive to sustain that environment + may not adapt to their environment/breed successfully

Question 63

Botanic gardens

Answer 63

-plant species are managed to provide best resources to grow i.e soil nutrients, watering, pesticides -can conserve wild varieties of crop as a potential source of genes

Question 64

Seed banks

Answer 64

-often used alongside in situ methods -seeds are dried and stored at cold temps to maintain viability and slow down loss of ability to germinate--} can be used to grow new plants in the future

Question 65

Captive breeding programmes

Answer 65

-produce offspring in a human-controlled environment--} gradually reintroduce stable, healthy population back into the wild -can import suitable breeding partners from other zoos to introduce new alleles -can maintain genetic diversity by keeping history log of breeding--} prevent inbreeding/reduction of gene pool

Question 66

What are conservation agreements?

Answer 66

-local + international cooperation to ensure preservation of species/habitats

Question 67

The Rio convention on Biological Diversity(CBD)

Answer 67

-aims to develop international strategies on the conservation of biodiversity and how to use animal and plant resources sustainably -international law that conserving biodiversity is a collective responsbility

Question 68

CITES agreement

Answer 68

-Convention on International trade in Endangered Species -increases international cooperation in regulating wild animal + plant specimens -member countries all agreed to make it illegal to trade products made from endangered animals i.e rhino ivory -raises awareness of threats to biodiversity via education

Question 69

The Countryside Stewardship Scheme 1991 (UK)

Answer 69

-aims to conserve wildlife and biodiversity + to improve and extend wildlife habitats by promoting specific management techniques to landowners -landowners offered 10 year pay agreement if they followed the management technique suggested -i.e regenerate hedgerows -10,000 agreements by the year 2000--} rebuilt species i.e birds

Question 70

What is preservation?

Answer 70

-protection of an area by restricting human interference -aims to protect environmentally sensitive ecosystems i.e -Galapagos islands= dodos became extinct due to introduction of other animals by humans -Antartica

Question 71

Fishing quotas

Answer 71

-limits on how much fish can be hunted per year -fishing net mesh size regulations= larger mesh so smaller fish can pass through and reproduce -preserved areas where no fishing is allowed