Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Section 7 - Populations in ecosystems > Flashcards

Section 7 - Populations in ecosystems Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is population size?

A

Number of individuals in a population at a given time

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

What is exponential population growth?

A

When resources are unlimited, populations exhibit exponential growth.
(J-shaped curve)

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

What is logistic population growth?

A

When resources are limited, populations exhibit logistic growth.

Population expansion decreases as resources become scarce.

Levels when carrying capacity of the environment is reached.
(S-shaped curve)

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

How does temperature affect population growth?

A

Lower temperatures lower metabolic rate so enzymes work more slowly.

Higher temperatures could denature enzymes

Low and high temperatures affect carrying capacity of a population

As more energy is being used to maintain bodies optimum temperature, less energy for growth and reproduction so carry capacity is reduced

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

What is the carrying capacity?

A

Each population has a certain size that can be sustained over a long period of time and this is determined by limiting factors.

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

How does light affect population growth?

A

Source of energy, rate of photosynthesis increases as light intensity increases.

Carry capacity is increases
(plants grow faster, more source for animals)

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

How does pH affect population growth?

A

Affects action of enzymes

Higher pH may denature enzymes, lower pH may decrease rate so enzymes work more slowly

Decreases carrying capacity of a population

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

How does water and humidity affect population growth?

A

Lower water, populations are small and only species that have adapted to dry conditions will exist

Humidity affects transpiration rates in plants and evaporation rates from animals

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

What is a habitat?

A

Place in an ecosystem where a particular population is found

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

What is ecology?

A

Study of inter-relationships between organisms and their environment

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

What is a microhabitat?

A

Small units within a habitat

mud at bottom of a stream

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

What is a niche?

A

Description of how a species functions within a habitat due to its adaptations

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

What is a biotic factor?

A

Living factors in an environment

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

What is an abiotic factor?

A

Non-living factors in an environment

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

What is an ecosystem?

A

How the community interacts with each other and the physical environment including abiotic factors

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

What is a community?

A

The sum of all the organisms in an ecosystem

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

What is a species?

A

Group of interbreeding organisms that produce viable and fertile offspring

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

What is intraspecific competition?

A

Competition between members of the same species

Availability of resources will determine size of population

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

What is interspecific competition?

A

Competition between members of a different species

Species will compete, dominant species will increase in population

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

What is the competitive exclusion principle?

A

Where 2 species are competing for limited resources, the one that uses the resources most effectively will eliminate the other

No 2 species can occupy the same niche definitively when resources are limited

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

What is the pattern of a typical predator-prey relationship in terms of population change?

A

Prey is eaten by predator
Predator population increases, prey decreases

Fewer prey means increases competition for food, so predator population decreases

Fewer predators means more prey survive, cycle begins again

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

What are reasons against counting every individual?

A

Time consuming

Damages habitat

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

What are methods of studying habitats?

A 
Bell transect
Frame quadrat
Pitfall trap
Light trap
Pooter
Sweep net
Drift net
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the 2 types of quadrat?

A

Point quadrat- bar with 10 holes where a pin could be dropped

Frame quadrat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are 3 factors to consider when using quadrats?

A

The size of the quadrat to use

The number of sample quadrats to record within the study area

The position of each quadrat within the study area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does mark-release-recapture do?

A

Generates an estimate of the population size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the equation for mark-release-recapture?

A

Number in 1st sample X number in 2nd second sample
/
Number of marked animals recaptured in 2nd sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the assumptions made for mark-release-recapture?

A

Only used for animals which are randomly distributed

Enough time must be allowed for the released animals to mingle

Method of capture must not alter the habitat

Marking method doesn’t harm animals, reduce chance of survival or affect behaviour patterns

Must be no migration or immigration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the mark-release-recapture method?

A
  1. Capture sample of species
  2. Mark in harmless way
  3. Release back into habitat
  4. Wait a week then take second sample
  5. Count how many are marked
  6. Use equation to estimate size
30
Q

Why would an animal be marked on their underneath and not back in mark-release-recapture?

A

Does not make them less camouflage so their chance of being prey is not reduced

31
Q

What is an effective method of random sampling?

A
  1. Lay 2 tape measures at right angles along study area
  2. Obtain coordinates by random generator
  3. Place quadrat at intersection of each pair and record species
32
Q

How would you use systematic sampling to find population size?

A

Using bell transect

Place string across ground in straight line

Move frame quadrat alongside line at regular intervals and record species within

33
Q

What is abundance?

A

Number of individuals of a species within a given area

34
Q

What are 2 ways of finding the abundance of a species that doesn’t move?

A

Frequency- likelihood in area

Percentage cover- estimate of area that species covers

35
Q

What is the advantage and limitation of percentage cover?

A

Useful where a species is hard to count

Data collected rapidly

Less useful where organisms occur in several overlapping layers

36
Q

What is the advantage and limitation of frequency?

A

Useful where species is hard to count

Gives quick idea of species present

Doesn’t provide information on density and detailed distribution

37
Q

Why are ecosystems described as being dynamic?

A

Populations constantly rise and fall

Any small change can have a large effect

Biotic and abiotic factors may alter conditions of ecosystem

38
Q

What is succession?

A

A change in a community over time

39
Q

What is primary succession?

A

Where an area previously without life is colonised by a community of organisms

40
Q

What is the pioneer species?

A

First species to colonise an area

Able to rapidly exploit sudden change in conditions

Grow quickly and usually short-lived

41
Q

What is the climax community?

A

Achieved once succession has gone as far as conditions will allow

42
Q

What is the process of primary succession?

A

Pioneer species colonise area

Change abiotic factors of environment

Allows more complex organisms to survive

43
Q

What effect does death and decay of the pioneer species have?

A

Adds organic matter creating basic soil.

44
Q

What are harsh abiotic conditions?

A

Decreased fresh water
Increases salt
Strong winds
No proper soil

45
Q

Why does plant diversity decrease at the climax?

A

Climax community organism takes light and stops other species growing

46
Q

What is a seral stage?

A

Each stage in succession

47
Q

What do successful pioneer species have?

A

Rapid growth
Rapid reproduction
Efficient seed dispersal
Tolerant to harsh conditions

48
Q

Why would species at earlier conditions at early stages disappear?

A

Shading by larger plants

Eaten by herbivores

Unable to compete

49
Q

What is secondary succession?

A

Succession when soil or vegetation is already present

50
Q

What common features emerge during succession?

A

Abiotic environment becomes less hostile

Greater number of habitats

Increased biodiversity

More complex food webs

Increased biomass

51
Q

What is the general name given to the first organisms to colonise bare land?

A

Pioneer species

52
Q

How do changes in the environment lead to increased biodiversity during succession?

A

Pioneer species die and form a soil with nutrients

Further colonisers can survive in soil

Environment is less hostile

More habitats and food sources available

Other species survive

Increased biodiversity

53
Q

What is the name of the stable, final stage of any succession?

A

Climax community

54
Q

What is an example of a plagioclimax community?

A

Intensive grazing by sheep can deflect succession from a forest climax community to grassland

55
Q

How might succession be managed in order to aid conservation?

A

Succession is prevented in order to preserve ecosystem

56
Q

What are the main reasons for conservation?

A

Personal- maintains our planet

Ethical- respect for living things

Economical- animals can make substances which can prove valuable

Cultural & aesthetic- variety adds interest to everyday life

57
Q

How might succession be managed in order to aid conservation?

A

Succession is prevented in order to preserve ecosystem

58
Q

What measures could be taken to prevent succession?

A

Cut back reeds to prevent them becoming dominant

Remove dead vegetation

59
Q

What is a niche?

A

The role and space that an organism fills within its habitat

60
Q

What is plagioclimax?

A

The climax community produced when succession is artificially stopped by human intervention

61
Q

Why would a student measure percentage cover of each species rather than counting individual plants?

A

To allow comparisons as plant sizes may vary

62
Q

A student carrier out a belt transect in an identical area at an identical time as another student but results were not the same.
Why?

A

There is a chance that one transect doesn’t represent the full habitat or community

63
Q

What are the abiotic factors that affect population growth?

A

Temperature

Light intensity (for photosynthesis)

pH (impact on enzyme action)

Water and humidity

64
Q

How should plants be chosen to get a representative sampling site?

A

Large sample area

65
Q

What is the role of the pioneer plants?

A

Make conditions less hostile

Soil development

Increase nitrogen

Provide shelter

Sustainable environment

66
Q

How could deflected succession be caused?

A

Grazing

Burning

Exposure to wind

67
Q

How does biomass change during primary sucession?

A

Increases

Plants at later stages are large

68
Q

How is stability maintained in a population with a high reproduction rate?

A

Limited food

Disease

Competition

69
Q

What are 2 limitations of the mark-release-recapture method?

A

Assumes no emigration

Assumes there is no death or birth

Assumes marking doesn’t affect survival

Assumes marked organisms don’t loose their mark

70
Q

Why is genetic drift more likely to affect an endangered species?

A

Endangered species so found in lower numbers

Genetic drift due to chance fluctuations in allele frequencies

More likely to affect smaller frequencies

Biology (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions