4/6 - ICH - Succession & samping Flashcards Preview

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Flashcards in 4/6 - ICH - Succession & samping Deck (32)
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1
Q

Define Species richness

A

Species richness = number of species in an ecosystem

2
Q

What results in a stable ecosystem?

  • What is the diversity like
  • What are the food webs
A

In less extreme environemnts:

  • Diversity of organisms is usually high
  • Biotic factors dominate and abiotic factors are not extreme
  • Food webs are complex - many inter-connected food chains
  • Results in a STABLE ECOSYSTEM - if population of one species declines, there’s alternative food sources
3
Q

What results in a unstable ecosystem?

  • What is the diversity like
  • What are the food webs
A

In extreme environments:

  • Diversity of organisms is generally low
  • Abiotic factors are extreme & few species have adaptations allowing them to survive ∴ abiotic factors dominate
  • Food webs are relatively simple - few food chainss or connections as few producers can survive
  • Results in UNSTABLE ECOSYSTEM - change in population of 1 species can cause really big problems for other species
4
Q

What is succession?

A

Succession = Th way different species which amke up a community change over time

5
Q

Define primary succession

A

Primary succession = New area of land has been newly fomed for exposed to bare rock. No soil/ organic material to begin with

6
Q

Define secondary succession

A

Secondary succession = Land where soil is present but there’s NO animal or plant species

7
Q

Define deflected succession

A

Deflected succession = Human activity that halts the natural succession process

8
Q

Define pioneer species and climax community

A

Pioneer species = First organisms to colonise a area

Climax community = Final stage of succession where the community is in a stable stage

9
Q

How is the diversity of a community expressed?

A

Simpsons index of biodiversity

N = Total no’ of organisms of all species in the habitat

n = Total no’ of organisms of each species

10
Q

What is ecological succesion? What is a sere?

A

Ecological succesion = The changes to an ecosystem over time

Sere = Each stage of succession

11
Q

What does each sere of succession result in?

A

A less hostile environment to increase the diversity

12
Q

5 adaptations of pioneer species

A
  • Produce large quantities of seeds/ spores which travel by wint to be deposited on new land
  • Seeds that germinate rapidly
  • Photosynthesise to produce their own energy
  • Tolerence to extreme envionments
  • Can fix N2 from the atmosphere so increase mineral content of soil
13
Q

Define plagioclimax

A

Plagioclimax = Stages in succession where artificial or natural factors prevent the natural climax community from forming

14
Q

What is a keystone species?

A

Keystone species = Species which a ecosystem depends upon. Loss of this species can lead to very large affects on the ecosystem

15
Q

Why must succession happen?

A

Environment is constantly changing, without adaptations the organisms would become extinct

16
Q

Why do pioneer species disappear quickly after succession beging to occur?

A

They highly specialised and are unable to compete well for resources

17
Q

2 ways to ensure that samples reflect the true population when investigating the numbers and distribution of a habitat

A
  • Take a relatively large sample
  • Ensure there;s no personal bias. Must be an random to avoid observer bias
18
Q

Explain what is happening in the graph to abiotic conditions, plants and the animals in the sand dune

A
19
Q

What can be used to represent the abundance of a plant when sampling a habitat?

A

The % cover

20
Q

Name 2 forms of random sampling

A

Quadrats and transects

21
Q
  • What type of quadrats can you get?
  • What is each type used for?
  • How are they used?
A

Frame quadrat:

  • Placed on the ground at random points. Count the number of the squared that have the plant to find population density, freq or % cover
  • Used to study distribution of plants in a fairly uniform area

Point quadrat:

  • Quadrat with a reduced size to a single point
  • Used to study the distribution of plants. Point quadrats are often used with transects
  • Point frame is usually used of approx 10 pins 5cm apart. By lowering the pins in turn and recording the no’ of hits on a particular species of plant, freq or % cover can be estimated
22
Q

What are the different types of transects that can be used in sampling?

A

Line transects:

  • Tape measure is placed along the transect and the species that touch the tae measure are recorded

Belt transects:

  • Data is collected along the transect using frame quadrats placed next to each other

Iterrupted transects:

  • Instead of investigating the whole transect of either a line or a belt, you can take measurements at intervals e.g. by placing point quadrats at right angles to the direction of the transect at set intervals along its length e.g. every 2m
23
Q

How do you ensure there is no observer bias during sampling?

A

In short:

  • Make a grid
  • Give the grid coordinates
  • Use some form to randomly generate the numbers for the coordinates
24
Q

What are the 3 measures to describe the distribution fo plants?

A

Population density = No’ of individual plants of a particular species in a given area

Frequency = Based on no’ of quadrats (ordinary or point) in which the species occur in e.g. 3 out of 10 pins hits a dandelion plants, freq = 30%

% cover = Measures proportions of the ground in a quadrat occupied by a species

25
Q

Give 3 methods to sample animals that are moving

A

Aquatic animals = net

Flying insects = Sweepnet

Ground insects = Pitfall trap

26
Q

Decribe another method used in sampling by which allows the estimate population size to be made of active animals

A

Mark, release, recapture:

  1. Use a trapping method to capture a no’ of animals fom the population begin investigated
  2. Mark these animals in a way that causes no hard + is inconspicious
  3. Release them + allow sufficient time for them to disperse back into the population which they have been taken from
  4. Useing precisely the same trapping method at the start, capture a second sample. Count the no’ of the animals that are marked and the no’ that are not marked

Estimated pop = (no’ of animals released x total no’ of animals in 2nd sample) / no’ of marked in second sample

27
Q

Formula for estimated population size = ?

A
28
Q

What are the 3 types of non-random sampling?

A

Opportunistic

  • Weakest form of sampling as it may not be represntative of the popultion
  • Uses organisms that are conveniently available

Stratified

  • Some populations can be divided into a number of strata (sub-groups) based on a partcular characteristic
  • A random sample is then taken from each of these strata proportional to its size

Syetematic

  • Sampling different areas within an overall habitat
  • Using a line or belt transect
29
Q

Formula for species index of biodiversity

What does the answer indicate?

A

N = total no’ of organisms of all species in the habitat

n = total no’ of organisms of each species

The closer to 1 the answer is, the more diverse the habitat

30
Q

Define genetic diversity

A

Genetic diversity = Variation of alleles within a species

31
Q

Define species diversity

A

species diversity = The number of different species (species richness) and the abundance of each species (species eveness) in an area

32
Q

Define Habitat diversity

A

Habitat diversity = The number of different habitats in an area