Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology A-Level > Populations in Ecosystems > Flashcards

Populations in Ecosystems Flashcards

1
Q

Define habitat

A

Place where an organism lives

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

Define population

A

Group of individuals of same species living in particular habitat + able to interbreed

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

Define community

A

Populations of diff species in a habitat

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

Define ecosystems

A

Self contained area made up of living + all the non-living factors

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

Define abiotic conditions

A

Non-living fts of the ecosystem

Eg. temp + water availability

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

Define biotic conditions

A

Living fts of the ecosystem

Eg. predators + food

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

Define niche

A

Roles of a species w/in its habitat

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

Why can a niche only be occupied by 1 species?

A

Bc the 2 species will compete until only 1 is left

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

Do 2 species ever occupy the same niche?

A
  • No
  • Own unique niche
  • Look similar but have slight differences eg. what they eat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define adaptations

A

Fts that inc chances of survival + reproduction

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

Adaptations can be:

A
  • Physiological
  • Behavioural
  • Anatomical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Give eg. of organisms adapting to abiotic conditions

A
  • Otters : webbed feet - can hunt + live on land + water
  • Seals : thick layer of blubber - keep warm
  • Hedgehogs : hibernate - lower rate of metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give eg. of organisms adapting to biotic conditions

A
  • Sea otter : use rocks to smash shellfish
  • Male frogs : produce mating calls
  • Bacteria : produce antibiotics, kills other bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define population size

A

Total no. of organisms of 1 species in a habitat

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

Define carrying capacity

A

Max stable population size of a species that an ecosystem can support

Varies as result of abiotic + biotic factors

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

Give examples of abiotic factors that affect the population size

A
  • Amount of light, water + space available
  • Temp
  • Chemical composition of env
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to the population size when the abiotic conditions are ideal?

A
  • Inc
  • Eg. ideal temp for metabolic reactions, don’t use up much energy maintaining body temp. More energy for growth + reproduction
18
Q

Give examples of biotic factors that affect the population size

A
  • Interspecific competition - btw diff species
  • Intraspecific competition - w/in species
  • Predation
19
Q

Outline interspecific competition as a factor affecting population size

A
  • Btw diff. species for same resources
  • Resources available to both pop is reduced - both pop limited by lower amount of food. Less energy for growth + reproduction so population size dec
  • If 1 better adapted, likely to out-compete other species
20
Q

Outline intraspecific competition as a factor affecting population size

A
  • Same species compete for same resources
  • Pop inc when resources is plentiful, as pop inc, more organisms competing for same food + space
  • Resources become limiting - not enough so pop dec
  • Smaller pop means less comp for food + space, better for growth + reproduction - pop inc
21
Q

Outline predation as a factor affecting population size

A
  • Pop size of predators + preys are interlinked
  • As prey pop inc, more food for predators so pop inc
  • As predator pop inc, more prey eaten so prey pop fall
  • Less food for predator so pop dec
22
Q

Outline how to carry out a random sample

A
  • Choose an area to sample - set up tape measure
  • Use random no. generator to generate coordinates - avoid bias
  • Repeat to reduce likelihood that results are due to chance
  • Estimate by multiplying mean by area size
23
Q

Define non-motile organisms

A

Organisms that don’t move - plants

24
Q

What is used to investigate non-motile/slow organisms?

A
  • Quadrats
  • Transects
25
Describe how you would use a quadrat to investigate non-motile organisms
* **Set up tape measure** * Using **random no. generator**, generate **co-ordinates** * **Place quadrat** at co-ordinates - **Species freq**: **count no. diff species** in each quadrat - **Percentage coverage** : count how much of **quadrat** is **covered** - **quicker**
26
When are transects used?
Find how plants are **distributed across** an area
27
What are diff types of transects?
* **Belt transect**: **quadrat** placed **next** to **each other** * **Interrupted** belt transect: quadrat placed at **regular intervals** (cover **longer distance**)
28
Describe how you would use a transect to investigate non-motile organisms across an area (4)
* **Lay tape** * Take **samples** at **regular intervals** * Using **quadrat** * Count **no**/**percentage coverage** * Use **several** transects
29
What is used to investigate motile organisms?
**Mark-Release-Recapture**
30
Outline how to carry out mark-release-recapture to investigate motile organisms
* **Capture sample** + **count** * **Mark** them in **harmless** way * **Release** * **Wait** until **re-intergrate**, take **2nd sample** from **same pop** * **Count** how many are **marked** * Use equation : ## Footnote **Total pop = no. 1st sample x no. 2nd sample / no. marked 2nd sample**
31
Outline the assumptions when carrying out mark-release-recapture
* Marked sample has had **enough time** to **re-intergrate** * Marking **hasn't** affected **chances of survival** * **Marking** is **visible** * **No changes** in **pop size** (**births**, **deaths** + **migration**)
32
Why are ecosystems described as being dynamic?
They're **constantly changing**
33
Define succession
**Change** in ecosystem **over time** due to **abiotic** + **biotic** conditions
34
What are the types of succession?
* **Primary** succession - land that been **newly formed/exposed**. **No soil/organic material** to start w/ * **Secondary** succession - land thats been **cleared** of all **plants** but **soil remains**
35
Outline what happens during primary succession
* **Pioneer species** (seeds + spores) blown by **wind** + **grow** * **Abiotic** conditions are **hostile** - pioneer species grow bc **adapted** to cope * **Change** abiotic conditions - die + **microorganisms decompose dead organic material** (humus). Forms **basic soil** * Makes condition **less hostile** eg. basic soil able to retain water, **new organisms** w/ diff. adaptations move, grow + die, making **soil richer** - **larger plants** grow * **New species change** **env** so **less suitable** for **previous** species
36
Outline what happens during (secondary) succession
* **Pioneer species** = **larger** plants * Each stage, **diff plants** + **animals better adapted outcompete** previous species, become **dominant species** * As succession goes on, **ecosystem** becomes **complex** + **biodiversity inc** * **Final stage = climax community** * **Won't change** bc in a **steady state**
37
Define climax community
**Stable/final community**
38
The species making up the climax community depends on what?
**Climate**
39
Define plagioclimax
When human activity **artificially prevent sucession**, **preventing** **climax community** from **developing**
40
Define conservation
**Protection** + **management** of ecosystems in a **sustainable** way
41
What are different ways to manage succession as a way of conserving?
* **Animal grazing** - **eat growing points** * **Managed fires** - **secondary succession** will occur
42
Give examples of different conserving techniques
* **Plants** use **seedbanks**, **stores** seeds from **diff plant** species. If plant becomes **extinct**, stored plants used * **Fishing quotas limits** amount of certain **fish species** caught * **Protected areas** (nature reserves) protect habitats by **restricting urban development, industrial development + farming** * **Endangered species bred** in **captivity**

Biology A-Level (10 decks)

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