B4.1 - Ecosystems Flashcards Preview

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Flashcards in B4.1 - Ecosystems Deck (61)
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1

What do arrows on a food chain show?

- the transfer of biomass
- transfer of energy

2

what is the difference between a food chain and a food web?

a food chain is a small section of the whole food web

3

what do food chains show?

the feeding relationship in an ecosystem

4

what are producers?

organisms that make their own food through photosynthesis

5

what are primary consumers?

animals that eat plants or algae (herbivores)

6

what are secondary consumers?

carnivores that eat herbivores

7

what is a tertiary consumer?

a carnivore that eats other carnivores

8

what are apex predators?

carnivores that have no other predators

9

what are decomposers

organisms that get energy from feeding on dead materials

10

what are consumers?

organisms that cannot make their own food and so have to eat other organisms

11

what are trophic levels?

each step in the food chain (where they feed)

12

what is a community?

organisms living within an ecosystem

13

define population

the total number of organisms of each species

14

what happens when an organism grows?

increases its biomass

15

state the factors affecting ecosystems and give a brief description

- biotic (living - beech trees, squirrels, hedgehogs)
- abiotic (nonliving - amount of rainfall, temperature of ecosystem)

16

what biotic factors affect communities?

- food availability
- breeding partners
- COMPETITION
- new pathogens

17

how does light intensity affect communities?

- greater light available = greater plant success
- plants adapt for maximum absorption (larger leaves in low light)

18

how does temperature affect communities?

- affects enzymes controlling metabolic reactions
- plants develop faster

19

what type of animals are affected by their external environments?

ectotherms (lizards)
rely on the sun to warm up

20

how does low moisture level affect plants?

- causes plants to wilt (low turgor pressure)
- water needed to keep cells turgid
- affects photosynthesis

21

what does the pH of soil affect?

- biological activity in soil
- availability of certain minerals

22

what kind of plants grow better in acidic soils?

ferns

23

what do plants need to survive? (5)

- light
- water
- carbon dioxide
- minerals
- space

24

what do animals need to survive?

- food
- water
- breeding partner
- space
- shelter

25

define population

the number of organisms of each species living in an area

26

what is interdependence within a community?

how different organisms depend on each other

27

what are ecological relationships?

interactions between organisms

28

what are the three main types of ecological relationships

- predation
- mutualism
- parasitism

29

what is predation the relationship of?

- relationship between predator and prey
- size of predator population directly affects prey population
- cyclic relationship

30

what is mutualistic relationship?

- both organisms benefit

31

give an example of a mutualistic relationship

bees taking pollen from plants
(bees can make honey, plants become fertilised)

32

what is a parasitism relationship?

one organism gains (parasite), other suffers (host)

33

give an example of a parasitism relationship

tapeworms in a human’s digestive system

34

what is commensalism?

one organism benefits from, but the other one is unaffected

35

what is an example of a commensalistic relationship?

tree frogs use plants as protection

36

what is a biotic factor?

a factor relating to animals (ie. competition of mating)

37

what is an abiotic factor?

a factor which is not living? (ie. rainfall)

38

why do food chains not exceed 4/5 tertiary levels?

not enough energy can be transferred to sustain life processes) - because of 10% rule

39

what does a pyramid of numbers show?

- the population at each trophic level (how many there are)

40

what do pyramid of numbers not take into account?

the size of the organism present

41

how do scientists calculate biomass?

- get dead organism
- dry the organism in a kiln (evaporate water mass)
- then measure it

CALLED DRY MASS

42

how do scientists calculate the total biomass at each trophic level?

measure average mass of each organism and multiply by the number of organisms present

43

state three reasons biomass is lost between trophic levels

- not all organism is eaten (animal bones/ plant roots)
- biomass is used during respiration
- some parts of organism cannot be digested (hair/teeth)
- released as waste products (excretion/ urine)

44

what is the nutrient cycle?

the process in which materials are passed between biotic and abiotic components of an ecosystem

45

what is carbon used to make?

GLUCOSE which makes...

- carbohydrates
- fat
- dna
- proteins

46

in what form can organisms use nitrogen?

when part of a compound (like a nitrate)

47

why do organisms use nitrogen?

- DNA
- proteins

48

Apart from providing water to organisms, describe another benefit of then water cycle

transports nutrients (helps replenish nutrients in different habitats)

49

how is carbon removed from the atmosphere?

- photosynthesis
- when animals eat plants

50

how is carbon released back into the atmosphere?

- respiration
- decomposition
- burning fossil fuels

51

how does the level of atmospheric carbon vary throughout 24 hours?

- decreases during daytime (photosynthesis)
- increases during nighttime (no photosynthesis, but respiration continues)

52

what are decomposers?

microorganisms which break down or decay dead organic matter at a microscopic level

53

how do decomposers help the nutrient cycle?

release nutrients (can be recycled)

54

what are detritivores?

small animals which shred organic material to small pieces (create larger surface area for decomposers)

55

how do decomposers release nutrients?

- bacteria and fungi release enzymes
- break down organic materials
- absorb soluble nutrients + use them for growth
- some others released into soil

56

how do temperatures affect rate of decomposition?

- too high = enzymes used by microorganisms denature (they die)
- too low = rate of enzyme controlled reactions too slow

57

how does lack of water in environments affect rate of decomposition?

- not enough water = reactions slow down/stop

58

how does lack of oxygen affect decomposition?

decreases, oxygen needed for microorganism to respire (so cannot survive)

59

what is the equation to calculate the rate of decay of material?

rate of decay (g/day) = change in mass (g) / time (day)

60

give 3 examples of detritivores

- earthworm
- woodlouse
- maggot

61

what 3 factors affect rate of decomposition?

water level, temperature, oxygen level