Ecosystems Flashcards

1
Q

what is an ecosystem?

A

made up of all living organisms that interact in a defined area, and the physical factors present. they can vary in size and are dynamic.

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2
Q

what is a biotic factor?

A

living factors.
e.g. predators, competition, mutualism/parasitism

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3
Q

what is an abiotic factor?

A

non living factors
e.g. temperature, water, humidity, light, wind, carbon dioxide

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4
Q

why do abiotic factors often have a bigger effect on plants than animals in an ecosystem?

A

plants are unable to hide / shelter / migrate in extreme conditions
plants are more reliant on light/water in order to photosynthesise
animals can regulate internal body temp

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5
Q

what is a species?

A

organisms with similar features which reproduce to produce fertile offspring

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6
Q

what is a population?

A

a group of individuals of the same species that occupy the same habitat at the same time

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7
Q

what is a community?

A

all populations of different species living in the same place at the same time

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8
Q

what is a biome?

A

a large scale ecosystem defined by abiotic factors such as weather

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9
Q

what is a biosphere?

A

an area of the planet where organisms live, including the ground, water and air

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10
Q

why are ecosystems dynamic but stable?

A

population sizes rise and fall due to interactions between organisms and the environment. any small change can affect the other in predator/prey relationships

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11
Q

what does niche mean?

A

the role of an organism in its ecosystem e.g where it lives

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12
Q

what does habitat mean?

A

the place where an organism/community lives

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13
Q

what is a keystone species?

A
  • significant effect on ecosystem
  • could be relied on by other organisms
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14
Q

what is a dynamic ecosystem?

A

constantly changes over time

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15
Q

what is a trophic level?

A

each stage in a food chain

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16
Q

what are food chains/webs used to demonstrate?

A

transfer of biomass (energy) through organisms in an ecosystem

17
Q

describe the first trophic level

A

producer - an organism that converts light energy into chemical energy via photosynthesis

18
Q

why is there a limited number of trophic levels?

A

there is not sufficient biomass and stored energy left to support further organisms

19
Q

what is the role of decomposers?

A

break down dead organisms and release nutrients back into the ecosystem

20
Q

what is ‘biomass’?

A

the mass of living material present in a particular place or organisms

21
Q

how would you calculate the biomass at each trophic level?

A

biomass present x total number of organisms in trophic level

22
Q

what is meant by ‘ecological efficiency’?

A

the efficiency by which biomass/energy is transferred

23
Q

what makes up the biomass?

A

cells and tissues composed of carbon compounds

24
Q

what are units for biomass on land and water?

A

land = gm-2
water = gm-3

25
Q

how is biomass measured?

A

discount water and measure the mass

26
Q

why is it important to not consider the water and use dry mass?

A

organisms have varied amounts of water

27
Q

what are the limitations of pyramids of biomass?

A

fails to consider how climate plays a role in trophic level activities

28
Q

how are biomass and energy linked?

A

light energy is captured by plants and transferred to organic compounds, forming biomass.
- therefore biomass can be equated to energy content

29
Q

what is meant by gross primary production?

A

the rate at which chemical energy is stored by producers

30
Q
A