Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biology > Populations In Ecosystems > Flashcards

Populations In Ecosystems Flashcards

1
Q

The larger the sample ………

A

The more reliable the data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why should the student not stop collecting data half way up the graph

A

Because the line has not reached the plateau so all the data is not being represented

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why should the student stop collecting data after the line plateaus

A

Because it would not improve the outcome of the data and would be a waste of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How would you decide the number of samples to take to collect representative data

A

Calculate the running mean after 10 samples and continue until it stops increasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does a point quadrat do

A

Measures the frequency of how often a species is found

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does a frame quadrat do

A

Measures percentage cover of a species in an area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3 things to consider when using quadrats

A

Size of the quadrat depending on the size of species measured and how they are distributed in an area
Number of samples being taken in the area - the more samples the more reliable
Position of each quadrat to produce unbiased results - random sampling must be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why use random sampling in a uniform area

A

Avoid bias
Representative data
Allows for the use of statistical tests

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Random sampling method

A

Set out a grid using tape measures at right angles
Divide into coordinates
Use a random number generator to pick coordinates
Count organisms in the quadrat on each coordinate
Record data
Repeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How to measure data in an irregular size area

A

Divide into spaces and number them
Use random number generator to pick space
Place quadrat
Count
Repeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When to use a belt transect

A

When the area varries and the abundance/ distribution of organisms changes
Measures percentage cover

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Method using a belt transect

A

Lay out a tape measure and place quadrat frame at right angles at regular intervals
Use a pin quadrat to count species touching the pins
Flip quadrat frame over to the other side of the transect and repeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Advantages of belt transect

A

Gives more info on abundance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Disadvantages of belt transect

A

Takes longer than a line transect
Might damage environment from standing on it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Frequency of species equation

A

Number of quadrat contains species / total number of quadrats X 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Method of mark release recapture

A

Capture a number of animals
Mark them
Release them and allow for reintegration
Collect second sample
Count and record
Use MRR equation to estimate population size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

MMR equation

A

Organisms in sample 1 X organisms in sample 2 / number of marked organisms recaptured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

MRR assumptions

A

Proportion of marked to unmarked in sample 1 and 2 is the same as the whole population
Marked sample distributed themselves evenly
Population have definite boundaries
Few births and deaths
Marking method is not toxic and more liable to predation
Mark has not rubbed off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is succession

A

Change in community over time due to changes in abiotic and biotic factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does succession change over time

A

Starts with pioneer species in harsh abiotic conditions and low diversity
Biodiversity increases over time and then becomes a climax community with more stable abiotic conditions
Biodiversity is lower because more dominant species outcompete others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do the first species colonise an area

A

Wind dispensable seeds to reach isolated areas
Rapid seed germination
The ability to to photosynthesis
Ability to fix nitrogen because soil has no nutrients
Tolerant to extreme conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is soil made by pioneering species

A

Weathering of rock and decomposition of dead organisms add nutrients to the soil which means more small plants colonise like Moses and ferns and the area become hostile
Process repeats and a thicker layer of developed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why do pioneer species become replaced by other species over time

A

Competition prevents pioneer species from photosynthesising or absorbing water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a climax community

A

A stable community where no further succession occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How do successional changes effect animals
Depending what plants are present depends what animas are present because of food source availability Flowering plants bring pollinators
26
Features of succession
Abiotic factors become less hostile Greater variety of habitats and food sources More complex food webs lead to more competition Increase in biomass
27
What is secondary succession
The same a primary succession accept it starts from wildfires , tsunamis, hurricanes , deforestation clearing and area of land But it happens quicker because seeds are already in the soil and from animal poop
28
How does dead organic matter change during succession
Increases because animals poop adding to soil and plants grow, die and decompose
29
How does humidity change during succession
Increases because rate of transpiration locally increases and air movement decreases due to plant protection
30
How does PH change during succession
Decreases because rain leaches basic ions from sea spray out of sandy soil and more plants die and decompose
31
How does rate of evaporation change during succession
Decreases because humidity increases so water potential decreases
32
How does sodium chloride conc change during succession
Rain leches basic ions out of Sand soil Less sea spray reaches ground
33
How does soil temp change during succession
Increases because soil composition increases in dead organic matter so drainage decreases which increases water content
34
How does wind speed change during succession
Decreases because plants provide a wind break so air movement decreases
35
How is marram grass adapted
Hairs , stomata and rolled leaf shape reduces conc gradient of water by diffusion Thick waxy cuticle avoids evaporation of water
36
What is ecology
The study of relationships between organisms and their environment
37
How does competition effect a population
More competition means less chance of getting food so organisms die
38
How does predation effect a population
More predation means prey population decreases
39
How does disease effect a population
More disease causes a population decrease
40
How does food availability effect a population
More food available means more population growth
41
How does temp effect population
Lower temp means less vegetation growth so more animals die of starvation
42
How does pH effect population
Incorrect pH means that vegetables can’t grow so more animals die of starvation or other food sources decrease
43
How does water availability effect population
Less water causes dehydration for animas and plants can’t grow
44
How does light effect population
Low light means plants can’t photosynthesis so can’t grow
45
How does natural disasters effect a population
Kills animals prevents them from reaching food , kills the food source
46
What is a micro habitat
A small pocket within a habitat E.g pythons live on trees but wood lice live in the bark cracks
47
What is intraspesific competition
Competition of individuals within the same species
48
What is interspesific competition
Competition between individuals of different species
49
Why is it difficult to obtain valid data on predator - prey relationships
The labs results are not accurate because the environment is limited so their are no external factors Whilst in the wild it is impossible to count every individual
50
what is carrying capasity
maximum population that can be supported by an environment long term
51
why is their a lag time in the first phase of a population growth curve
because organisums are acclimatising to the environment so no reproduction
52
why is their exponential growth in the second phase of a population growth curve
reproduction rates high - birth rates higher than death rates
53
why is there fluctuation in the final phase of population growth curve
lots of intraspesific competition because population is over carrying capasity and then a limiting factor will bring down the population
54
how will the population growth curve change for bacteria
it is quicker because bacteria reproduces quicker less ossilation in stage 3 then a decline phase because food in a petri dish runs out
55
how does temperature effect cold blooded organisums populations
if temp is lower enzymes work more slowly so metabolic rate is lower so carrying capasity is lower if temp is higher enzymes denature reducing carrying capasity
56
how does temperature effect warm blooded animal populations
they can maintain constant body temperatures but the further from optimum temp the more energy used to maintain temp so less available for reproduction so reduced carrying capasity
57
how does light effect population size
more light alllows more photosynthesis so more plant growth and food availabilty carrying capasity increases
58
how does pH effect population size
as you move away from the optimum more enzymes denature so less enzyme substrate complexes so carrying capasity decreases
59
how does water and humidity effect population size
more water means plants can grow more because it allows for more photosynthesis so acrrying capasity increases
60
what is polarding and when is it done
chop canopy off the tree and it will grow again done because grazing animals are around and they would eat the sprouts if they are low enough
61
what is coppicing and when is it done
cut the tree down really low to a stump over time the stump grows new sprouts done because it was over dominating other plants
62
why is controlled heath burning done
kills dominanting species heat activated seeds germination of other species

biology (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions