13.1 Investigating population Flashcards

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1
Q

Species

A

Group of closely related individuals that have the ability to interbreed and produce fertile offspring

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2
Q

Population

A

All the individuals of a given species living together in the same area at the same time

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3
Q

Carrying capacity

A

The maximum equilibrium number of organisms of a particular species that can be supported indefinitely in each stable environment

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4
Q

Community

A

All the individuals of all the species living together in the same area at the same time

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5
Q

Habitat

A

The place where all the organisms live within an ecosystem

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6
Q

Niche

A

Where an organisms lives and what it does, how it feeds and interacts with other organisms and the environment

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7
Q

What is the advantage of organisms occupying different niches?

A

Less overlap, therefore less competition between species and are more likely to coexist

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8
Q

Interspecific competition

A

Competition for resources between organisms of different species

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9
Q

Intraspecific competition

A

Competition for resources between individuals of the same species

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10
Q

When should you use percentage cover?

A
  • When the organisms are too small to count
  • Too many individuals to count
  • Hard to identify
  • Overlap with another species
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11
Q

Reliability definition

A

When an investigation can be repeated and other people get the same results

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12
Q

How do you ensure reliability when sampling?

A
  • Sample sites must be selected at random to avoid bias
  • Large enough sample sizes and suitable for statistical analysis so the data is reliable and representative
  • Method of collection must be appropriate to species
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13
Q

How do you calculate species density?

A

Count all species present in quadrant

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14
Q

How do you calculate percentage cover?

A

The area of the quadratic covered by the species recorded as a percentage of the total area

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15
Q

How do you calculate frequency of species?

A

The proportion of quadrants that contain a particular species

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16
Q

Why do you use random quadrating?

A
  • To find out what species are present and their relative abundance a specific area
  • Compare the species between two areas
  • Compare the species abundance at one site at different seasons
17
Q

Random quadrating method

A
  1. Place two tape measures perpendicular to each other
  2. Use a random number generator to generate a series of coordinates
  3. Place a quadratic down at the intersection of one of these quadrants
  4. Abundance can then be estimated
  5. Continue until running mean has stabilised
18
Q

Equation for percentage cover

A

Total area covered by species / total area covered by quadrants x 100

19
Q

What is systematic sampling?

A

Transects, used for very slow moving animals or plants

20
Q

What are the different types of systematic sampling?

A

Transect - what species are touching the line at each sampling point
Belt transect - Placing two parallel lines across a meter apart and recording what species are found between the lines
Interrupted belt transect - Using one line and placing a quadratic every 5m and recoding abundance within the quadratic

21
Q

Describe how you would investigate the distribution of marram grass from one side of the dune to the other

A
  1. Transect from one side of the dune to the other
  2. Place quadrants every 5m
  3. Count plants in quadratic and calculate abundance
22
Q

Mark - release - recapture method

A
  1. Animals of a particular species are ethically collected (traps, netting or tranquilliser)
  2. The animals are marked in a way that doesn’t affect their ability to feed or make them more susceptible to predation
  3. Release the animals to disperse back into their population
  4. After a reasonable length of time, recapture the same sample size and note how many have already been marked
23
Q

Population size equation

A

N1 x N2/ Nm
N1 = number caught in first
N2 = number caught the second time
Nm = Number caught second time that were marked

24
Q

Consideration for mark release recapture

A

No immigration or emigration
No births or deaths

25
Q

What does biotic mean?

A

Living

26
Q

What does abiotic mean?

A

Non living

27
Q

Examples of biotic factors

A

Invasive species
human impact
Algae

28
Q

Examples of abiotic factors

A

WInd
Temperature
Altitude

29
Q

How does temperature affect organisms?

A

The higher the temperature, denatures enzymes so overall activity decreases
The lower the temperature, the enzymes don’t have enough kinetic energy to catalyse reactions, overall activity decreases
More extreme the temperature, fewer species able to survive

30
Q

How does light intensity affect organisms?

A

The higher the light intensity, the greater the rate of photosynthesis, population will increase faster

31
Q

How does water availability and humidity affect organisms?

A

Lower the humidity, the more water loss will occur
Organisms tend to loose a lot of water anyway due to transpiration

32
Q

How does pH affect organisms?

A

The more extreme the pH, the more it affects an organism and the lower the population size and range of species

33
Q

What are biotic factors?

A

Factors affecting the distribution and size of populations which are related to presence of other organisms

34
Q

What is predation?

A

When one animal species (predator) feeds on another a animal species (prey)
It normally involves killing the prey

35
Q

Examples of how predators have adapted to be able to capture prey

A

High speed
Venomous secretions

36
Q

Examples of how prey have adapted their defence mechanisms

A

Camouflage
Protective spines

37
Q

Explain a prey predator graph

A

The population of prey increases, there is more food for predators so intra-specific competition reduces and predator numbers increase
More prey is consumes, prey population falls, Intra-specific competition increases as predator population increases, predator population falls again and the prey population starts to recover