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Gcse Biology > B4 Ecosystems > Flashcards

B4 Ecosystems Flashcards

1
Q

Producers

A

Organisms that make their own food by photosynthesis (plants/algae)

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2
Q

Consumers

A

Organisms that can’t make their own food, have to eat other organisms to gain energy (all animals)

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3
Q

Decomposers

A

Special group of consumers, gain energy by feeding on dead/decaying material

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4
Q

How is energy transferred to producers

A
  • energy from sun transferred by light to chlorophyll in cells of producer
  • photosynthesis takes place here (co2 & h2o react to make glucose)
  • glucose stores energy within its chemical bonds
  • glucose can be converted into carbs, fats, proteins: used as energy stores, growth, repair
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5
Q

Biomass

A

= mass of living material present (increases as organism grows)

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6
Q

How is energy transferred between organisms

A
  • consumers eat producers
  • when organism respires, energy stored in its food transferred in production of ATP
  • organism grows & biomass increases
  • process continues
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7
Q

Trophic level

A

Each step in a food chain

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8
Q

What do the arrows in a food chain show

A

The transfer of biomass (energy transfer) from one organism to the next

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9
Q

Trophic levels of a food chain

A
  • producer
  • primary consumer (herbivore)
  • secondary consumer (carnivore)
  • tertiary consumer
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10
Q

What makes food webs better than food chains

A

Food webs contain a series of interlinked food chains as most animals eat more than one type of organism

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11
Q

Biotic factors

A

Living factors

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12
Q

Biotic(living) factors of an ecosystem

A

Competition for:

  • food
  • space
  • breeding partners
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13
Q

Abiotic (non-living) factors

A
  • light intensity
  • temperature
  • moisture level (rainfall)
  • soil PH
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14
Q

How does light intensity affect communities?

A

Light required for photosynthesis,
greater light availability = greater success/growth of plant
Plants evolve to grow successfully in different light intensities (larger leaves in low)

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15
Q

How does temperature affect communities

A
  • temp affects enzymes which control metabolic reactions

- warmer temp = faster metabolism = more rapid development (for plants, cold blooded animals)

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16
Q

How does moisture level affect communities

A
  • lack of water = death (osmosis, wilt)

- needed for photosynthesis

17
Q

How does soil pH affect communities

A
  • soil pH affects biological activity & availability of certain minerals in soil
  • some plants (rhododendrons, ferns) grow better in acidic soil (pH 1-6)
  • some plants (cucumbers, cauliflower) grow better in alkaline soil (pH 8-14)
18
Q

What do plants need to survive

A
  • light
  • water
  • carbon dioxide
  • minerals
  • space
19
Q

What do animals need to survive

A
  • food
  • water
  • breeding partners
  • space (territory)
  • shelter
20
Q

Interdependence, 3 main types

A

= how different organisms depend on each other within a community

  • predation
  • mutualism
  • parasitism
21
Q

Predation

A

= Relationship between a predator & prey species

- Size of predator population directly affects size of prey population

22
Q

Mutualism

A

= both organisms benefit from relationship
(Eg. Oxpeckers are birds that eat ticks/fleas living on buffalos skin, gain food while buffalo free from irritation/disease)

23
Q

Parasitism

A

= only 1 organisms (parasite) gains, organism it lives off (host) suffers
(Eg. Tapeworms in animals digestive system, fleas)

24
Q

What do pyramids of biomass show

A

= population at each trophic level, bar width represents no. of organisms present

25
Q

What is the general trend as you move from 1 trophic level to the next

A
  • size of organisms (biomass) generally increases

- number of organisms generally decreases (except eg. oak tree)

26
Q

How to calculate biomass

A

Average dry mass of each organism x no. of organisms present = total biomass at trophic level

(Organism killed & dried in a kiln)

27
Q

When is biomass lost

A
  • not all of an organism is eaten
  • some biomass used in respiration
  • some parts of organism can’t be digested (hair), removed from body in faeces (egestion)
  • waste products produced by body lost through excretion (urine)
28
Q

How much chemical energy in a consumers food is converted to new body tissue

A

10%

29
Q

Why do very few food chains have more than 4 trophic levels

A

Not enough energy can be transferred to sustain life processes as less energy is transferred on each level

30
Q

Decomposers

A

Microorganisms (bacteria/fungi) that break down/decay
- dead organic material at a microscopic level
- animal waste (faeces/urine)
To release nutrients which can be recycled

31
Q

Saprophytes

A

Organisms that feed on dead material (decompose)

32
Q

Detritivores

A

Small animals that speed up decomposition by shredding organic material into very small pieces to create a larger surface area for decomposers to work on

33
Q

Examples of detritivores & material they break down

A
  • earthworm: leaves
  • woodlouse: wood
  • maggot: animal material
34
Q

How do decomposers release nutrients

A
  • bacteria/fungi release enzymes, break down substances into organic matter
  • absorb soluble nutrients into their bodies, use theme for growth/energy store
  • bacteria/fungi may be eaten by other organisms, nutrients passed on
  • some nutrients released directly into soil/environment
35
Q

What conditions do microorganisms decompose materials most efficiently in

A
  • warm temperatures
  • moist environments
  • aerobic conditions
36
Q

Why do temps affect rate of decomposition

A
  • high temps = enzymes in microorganisms denatured, prevents decomposition/death of microorganisms
  • low temps = rate of enzyme-controlled reactions slow = rate of decomposition slow/rate of microorganism replication slow
37
Q

Why do moist environments affect rate of decomposition

A
  • not enough water available = reactions within microorganisms slow down/prevented = reduces/stops process of decomposition
38
Q

Why do aerobic conditions affect rate of decomposition

A
  • oxygen needed for microorganisms to respire

- anaerobic conditions prevent most forms of decomposition as microorganisms can’t survive

39
Q

Rate of decay equation

A

Rate do decay (g/day) = change in mass (g) / time (day)

Gcse Biology (15 decks)

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