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Populations In Ecosystems Flashcards

1
Q

What is ecology

A

The study of inter relationships between organisms and their environment

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2
Q

Name the abiotic factors of an ecosystem

A

Light
Temp
Soil PH
water availability

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3
Q

How does light affect an ecosystem

A

Affects rate of Photosynthesis and so plant growth and so food availability as biomass is affected

More energy available for spore and seed formation with more light

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4
Q

How does temperature affect an ecosystem

A

Affects rate of Respiration and Photosynthesis due to enzymes.

Affects water availability

Affects body temp so energy used to regulate temp not growth and reproduction

Cold blooded= enzymes denature

Warm blooded= less energy for reproduction so mature slower

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5
Q

What biotic factors are there in an ecosystem

A

Food availability
Predation
Disease
Competition

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6
Q

How do predators affect an ecosystem

A

Kill organisms so reduce population

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7
Q

How does food availability affect an ecosystem

A

Competition

Starvation

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8
Q

How does competition affect an ecosystem

A

Some will starve and die reducing population

Not enough supply to support all

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9
Q

How does disease affect an ecosystem

A

Makes more succeptible to predation so may fall prey

May die from disease

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10
Q

Define population

A

All individuals of same species in same place at the same time

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11
Q

Define ecosystem

A

Habitat and the community of organisms within it

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12
Q

Define community

A

All populations of different species living at the same place at the same time

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13
Q

Define habitat

A

Place where an organism normally lives

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14
Q

Define ecological niche

A

Where an organisms lives and what it does

the biotic and abiotic factors its adapted to

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15
Q

Define the competitive exclusion principle

A

No two species can occupy the same ecological niche because they will outcompete one another

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16
Q

Define carrying capacity

A

The maximum size of the population able to be supported by an ecosystem

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17
Q

Describe the growth curve

A

Slowth then rapid and then fluctuations

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18
Q

Why is a logarithmic scale used

A

To clearly show the rate of growth

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19
Q

How does PH affect a population

A

Alter enzyme activity

Decreased Respiration and Photosynthesis so reduced carrying capacity

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20
Q

How does water and humidity affect a population

A

More humid = lower WP gradient= reduced transpiration and water loss

Less water = only adapted organisms survive

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21
Q

What are the two types of competition

A

Intra and inter

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22
Q

What does intraspecific competition occur for

A

Light water mates

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23
Q

What does interspecific competition occur for

A

Habitat light water food

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24
Q

How are predators adapted

A

Camouflage
Faster movement
Better sense to detect prey

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25
How are prey adapted
Camouflage Concealment behaviour Spines (protective features)
26
Why might lab results be different in terms of predator prey relationships
Prey will go extinct as no other source of food or refuges
27
What is a selection pressure
A factor that drives selection
28
Define succession
Gradual changes in community over time
29
Describe the process of succession
New species arrives changing the conditions making them less hostile, making them less suitable for the previous species and more suitable for other species which outcompete it.
30
What happens to biodiversity during succession
Increases and then decreases at climax community
31
Define pioneer species
First species to colonise
32
How are pioneer species adapted
Asexual reproduction (single organism can establish whole pop) Produce many wind dispersed seeds Rapidly germinating seeds Able to Photosynthesise (no other animals available) Fix nitrogen from air Tolerate extreme conditions
33
Define climax community
Stable community where no further succession occurs
34
What are the features of succession
``` Abiotic factors become less hostile Greater no and variety of habitats Greater biodiversity More complex food webs Greater biomass ```
35
Describe primary succession
Bare rock is colonated by lichens Weathering of rock and decomposition of dead lichen =soil and nutrients Nutritious soil can support a variety of life Biodiversity increases so environment is less hostile Thicker soil builds Flowers and ferns establish Climax community reached so species in equilibrium and biodiversity decreases
36
What is the difference between primary and secondary succession
Secondary begins with a devastated ecosystem where soil is available and succession is more rapid
37
How does DOM change with succession
Increases as more organisms are present which then die
38
How does humidity change with succession
Increases as more plants means more transpiration and less air flow
39
How does PH change with succession
Decreases as DOM is broken down into fatty acids and carboxylic acids
40
How does transpiration/evaporation change with succession
Decreases as more plants are present and so humidity decreases, decreasing the WP gradient
41
How does NaCl conc change with succession
Decreases as less sea spray hits the soil
42
How does soil temp change with succession
Increases as more plants means more Respiration so more energy released More decomposition so more DOM so less drainage and more water
43
How does wind speed change with succession
Decreases as more plants act as wind break
44
Define conservation
Management of earth's natural resources to. Maximise use in the future
45
Reasons for conservation
Personal (life support system) Ethical (species should be able to coexist) Economic (many genes able to produce many valuable substances) Cultural and aesthetics (inspiration for books and songs)
46
Why might we want to manage succession
So that rare species don't go extinct due to being outcompeted
47
How might succession be managed
Grazing of sheep | Burning
48
What organisms are quadrats used for
Non-motile organisms
49
Describe the types of quadrat
Frame Count organisms in squares Point Count organisms touching poles
50
What factors need to be taken into account when using quadrats
Size (large quadrats for large organisms) No of samples (large is more reliable but more time consuming) Position (random sampling to avoid bias)
51
What is a running mean and why is it used
Mean calculate everytime a new sample is taken When mean is constant the number of samples is representative
52
Describe random sampling using quadrats
``` Set out grid Randomly choose coordinates Place quadrat at coordinates Count organisms in quadrat Repeat 10 times and calculate Mean ```
53
Define systematic sampling and an example
Collecting data at regular intervals Belt transect
54
What's the difference between a line and belt transect
With a line transect quadrats are placed at regular intervals With belt transects the quadrats are placed every length of the quadrat
55
What are the advantages of belt transect over line transects
More accurate | Less bias
56
What are the disadvantages of belt compared to line transects
More damaging | More time consuming
57
Define abundance
Number of individuals of a species in an area
58
What are the ways to measure abundance
Percentage cover Frequency Population density
59
Describe how frequency is calculated
Expressed as a percentage or as a X out of y.
60
How is population density calculated
Number of individuals per area
61
What are the advantages and disadvantages of using percentage cover
Ad: Good when organisms are difficult to count Less time consuming Dis: Organisms may overlap making % over 100
62
What are the advantages and disadvantages of Using frequency
Ad: Quick and easy Dis: No information on density or distribution
63
When is Mark release recapture used
On motile organisms
64
What assumptions are made in MRR
Markings don't rub off Sample is proportional to population Organisms have enough time to mix Marking is non toxic and doesn't make them more likely to be prey No births or deaths No immigration or emigration
65
Outline method of MRR
``` Capture organisms Mark all Release and leave for 24 hrs Capture and ratio of marked to total captures Use ratio to calculate whole population ```

biology (28 decks)

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