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Biology Alevel > Biodiversity > Flashcards

Biodiversity Flashcards

1
Q

Biodiversity ?

A

Variety of living organisms in an area

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2
Q

Species ?

A

Group of similar organisms able to reproduce to give fertile offspring

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3
Q

Habitat?

A

Area inhabited by a species
- include abiotic and biotic factors

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4
Q

What levels can biodiversity be assessed ?

A

Habitat diversity - number of different habitats in area (sand dunes,woodland,meadows and streams)
Species diversity - no. Different species/abundacne of each species in area
Genetic diversity- variation of alleles within a species ( different breeds within species etc )

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5
Q

How can a sample to measure biodiversity be taken?

A

Choose area to sample
Count no. Individuals of each species
Repeat/take many samples for more REPRESENTATIVE RESULTS

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6
Q

Equipment used to take samples for different organisms?

A

PITFALL TRAP/POOTER - catch ground insects
TULLGREN FUNNEL- leaf litter/soil placed in funnel and light forces organisms to fall out funnel/be collected
KICK SAMPLING - kick bottom of the stream/use a net to collect organisms that have been disturbed
SWEEP NET - sweep net back and fry along grass to catch insects in grass

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7
Q

3 types of non random sample?

A

Systematic : samples taken at fixed intervals, often along a line (e.g quadrants placed at reg intervals, placed along transect )

Opportunistic: sample chosen by investigator

Stratified: different areas of habitat identified /sampled separately in proportion to their part of the habitat

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8
Q

What is species richness and species evenness ?

A

SPECIES RICHNESS : numbe of different species in an area
SPECIES EVENNESS : Measure of relative abundance of each species in an area

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9
Q

What is the Simpson’s Index of diversity ? Formula?

A

Takes into account SPECIES RICHNESS AND EVENNESS
- measures diversity
- closer to 1 the index is, the more diverse habitat is

D= 1 - (sum of (n/N)2 )
N= total no. Organisms of all species n= total number of individuals of one species

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10
Q

Importance of genetic diversity of a population?

A
  • increased variation means :
    more likely to have an adaptation that allows survival to environment changes
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11
Q

What is polymorphism ? How can we use genetic polymorphism to measure genetic diversity ?

A

Polymorphism - locus that has 2 or more alleles

Proportion of polymorphic gene loci = no. Polymorphic gene loci / total no. Loci

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12
Q

Factors effecting global biodiversity?

A
  1. Human population growth
  2. Increased use of monoculture in agriculture
  3. Climate change
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13
Q

How does human population growth affect biodiversity?

A

Habitat loss- decreases habitat diversity
Over exploitation - greater demand for resources means resources used up —> decrease genetic diversity /species diversity (from extinction e.g from overfishing)
Urbanisation- road development/cities isolate species , so populations can’t INTERBREED/genetic diversity is decreased
Pollution - pollutants kill species/destroy habitats

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14
Q

How does the increased use of monoculture affected biodiversity ?

A

Monoculture - growing of a single variety of crop
Due to this :
Loss of habitat - to clear land - reduce HABITAT DIVERSITY
Local/natural plants and animals destroyed with PESTICIDES/HERBICIDES —> reduce species diversity
Traditional crops lost - don’t make enough money so not planted anymore —> reduce species diversity

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15
Q

How has climate change affected biodiversity ?

A
  • areas get colder/hotter/wetter or drier

Causes change in :
Species distribution - species may have to migrate (reduce biodiversity in place they came from)
Extinction - if species can’t migrate/nowhere to migrate /change is to fast , causes EXTINCTION

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16
Q

Ecological reasons for maintaining biodiversity?

A

1. Protect species /KEYSTONE SPECIES
- organisms in ecosystem are interdependent so removal of one species DISRUPTS FOOD CHAINS /NUTRIENT CYCLES
KEYSTONE SPECIES - other species in ecosystem depend on keystone species - ecosystem change dramatically if not there e.g PREDATORS/MODIFIERS/HOSTS
Have significant effect on ecosystem

2. Maintain genetic resources
- materials from plants,animals, microoorganism that contain genes, that are valuable
Used for : food/drink, clothing, drugs, fuels, industrial materials
- genetic resources allow us to adapt to changes in environment - can use genes from plant to make drought resistant plants

17
Q

Economic reason for maintaining biodiversity?

A

To reduce soil depletion
- caused by continuous monoculture - planting same crop in same field without interruption

Soil depletion causes INCREASED SPENDING ON FERTILISERS/DECREASE YEILDS - economic costs

18
Q

Aesthetic reasons for maintain biodiversity?

A
  • attractive landscapes due to biodiversity
  • more tourism
19
Q

What is In Situ conservation and methods of this?

A

On site conservation - election of species in their NATURAL HABITAT
Methods:
National parks/wildlife reserves - restricts urban/industrial development
Control/prevention** species that threatens local biodiversity
**Protect habitats*
Promote particular species (by preaching food sources etc)
Legal protection to endangered species - illegal to kill them

20
Q

Advantages/disadvantages of in situ conservation ?

A

Ad : Both species/habitat conserved
Larger populations protected
Less disruptive
Population recovery chances are higher

Dis : difficult to control some factors that are a threat to a species

21
Q

What is ex situ conservation ? And methods to do this?

A

Off site conservation - move species from threatened habitat to new place

Methods :
Relocating to safer area
Breeding programs in captivity then put into wild when ready
Botanic gardens - controlled environs to grow rare plants for conservation/research
Seed banks - seeds frozen/stored in seed banks without losing fertility
- source of seeds if natural reserve destroyed

22
Q

Advantages/disadvantages of ex situ conservation?

A

AD: - protect individual animals in controlled environments - predation/hunting controlled
- Can be used to Reintroduce a species that have left an area

DIS : used for small no. Induviduals
- difficult /expensive to sustain right environment
- less successful than IN SITU - species can’t breed in captivity /don’t adapt to new environment

23
Q

Eg of international cooperations involved in species conservation?

A

RIO CONVENTION ON BIOLOGICAL DIVERSITY (CBD)
- aims to develop international strategies on conservation of biodiversity / use animal/plant resources in a sustainable way
- provide guidance to governments/made it a international law to conserve biodiversity

CITES agreement
- agreement to increase international cooperation in regulating trade in wild animals/plant specimens
- made it illegal to kill endangered species
- limits trade through licensing/illegal to trade products from endangered animals

24
Q

Example of a Local conservation agreement?

A

Countryside stewardship scheme (CSS)
- to conserve wildlife /biodiversity and improve/extend wildlife habitats by promoting managment techniques to landowners
Offered 10 yr agreement to pay landowners who followed management techniques (e.g refer as hedgerows /leave grassy margins)

25
Q

How can a pitfall trap be set up?

A

Dig hole and place container in soil
Leave overnight
Count no. species or organisms

26
Q

How does isolation speed up extinction ?

A

Hard to find a mate
- inbreeding leads to low genetic diversity - small gene pool
- cannot cope with environmental change

27
Q

PRACTICAL: Investigating Biodiversity using Sampling

CALCULATE POP DENISTY

A

Choose Sample Sites: use grid/to scale drawing of area /label with coordinates
Use random no. Generator to choose set of coordinates - AVOID SAMPLING BIAS

Calculating Pop density: place quadrant at generated coordinate /count no. Individuals in each quadrant
- use a running mean to determine the number of quadrats required to get a representative sample:
Find the mean number of individuals per quadrat for the first two quadrats found, then the mean of the first three, then the mean of the first four and repeat until there is no further significant change in the mean
To find estimated pop size for whole habitat/area , divide whole area by area of quadrant
Multiply this value by mean no. Individuals per quadrat

28
Q

PRACTICAL: Investigating Biodiversity using Sampling

Calculate abundance of species using % cover

A

Used for plants
- place grid quadrat at each randomly generated coordinate - each ² = 1% cover
Count no. Squares in each quadrat within which the species occupies over half the ²
- SAMPE PERSON DOES ALL SAMLES AS SUBJECTIVE

29
Q

PRACTICAL: Investigating Biodiversity using Sampling
Calculating abundance of a species using frequency (%)

A

Place frame quadrat at multiple coordinates generated
- count no. Quadrat that contain the species

E.g If 3 out of 10 quadrats contain the species the frequency is 30%

30
Q

What is species density/frequency?

A

SPECIES DENSITY: indicates how many individuals of that species are per unit area

SPECIES FREQUENCY: probability that the species will be found within any quadrat in the sample area

31
Q

limitation of quadrats?

A
  • only used for sessile/immobile species (plants/slow moving animals)
  • species that are high in numbers/very small require abundance to be calculated using percentage cover/frequency techniques - wont give estimated population size
32
Q

Mark - release -capture method : estimating pop size of mobile animals METHOD?

A
  1. First large sample taken - catch as many individuals as possible/counted and marked - wont affect survival
  2. Marked induviduals returned to habitat /randomly mix with rest of population
  3. After some time, another large sample is captured
  4. The number marked /unmarked individuals in sample is counted
  5. The proportion of marked to unmarked individuals is used to calculate POP SIZE

N = (n1 x n2) / m2
N = pop size estimate , n1 = no. Marked individuals released , n2 = no. Individuals in second sample (marked/unmarked) , m2= no. Marked individuals in second sample

33
Q

Assumptions used in mark-release-capture method?

A
  • marked individuals given enough time to disperse/mix back with rest of population
  • marking doesn’t affect survival rate - doesn’t make them more likely to be predated
  • marking remains visible throughout sampling
  • population stays same during study
34
Q

How to carry out a sample for line and belt transects?

A

For a line transect:
Lay out a measuring tape in a straight line across the sample area
At equal distances along the tape, record the identity of the organisms that touch the line. For example, every 2m- qualitative data

For a belt transect:
Place quadrats at regular intervals along the tape and record the abundance or percentage cover of each species within each quadrat
- can count no. Individuals of each species in each quadrat
This produces quantitative data

Biology Alevel (28 decks)

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