module 6.3.1: ecosystems Flashcards

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1
Q

what is a habitat

A

a place where an organism lives

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2
Q

what is a population

A

all the organisms of one species who live in the same place at the same time and can breed together

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3
Q

what is a community

A

all the populations of different species who live in the same place at the same time and who can interact with each other

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4
Q

what is an ecosystem

A

a community of animals, plants and bacteria interrelated with the physical and chemical environment. ecosystems can be referred to on a large scale, such as an African grassland, a medium scale, such as a playing field, or a small scale, such as a rock pool or a large tree

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5
Q

what is biotic factors

A

environmental factors associated with living organisms in an ecosystem that affect each, such as predation or disease. They impact each species and individual because all species in an ecosystem are interrelated

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6
Q

what is a producer

A

plants and photosynthetic bacteria that supply chemical energy to all other organisms, whilst the numbers of primary (feed on producers), secondary (feed on primary), and tertiary (feed on secondary) consumers will affect the populations of each other and the producers

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7
Q

what is a decomposer

A

bacteria, fungi and other organisms that feed on waste material or dead organisms

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8
Q

what is a abiotic factor

A

the nonliving characteristics of an ecosystem that affect other living organisms, such as the pH, relative humidity, temperature, and concentration of pollutants. at extreme values of an abiotic factor, a species may perform better or worse, or even die. examples include salinity, light, temperature, water and oxygen availability, and edaphic factors

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9
Q

what cause dynamic changes

A

due to change in and interaction between the biotic and abiotic factors

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10
Q

what are cyclic changes

A

repeat themselves in a rhythm such as the movement of tides and day length

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11
Q

what are directional changes

A

go in one direction, i.e: deposition of silt into an estuary, or erosion of a coastline

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12
Q

what are unpredictable/erractic changes

A

have no rhythm or constant direction, i.e: a sudden natural disaster

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13
Q

why is the transfer of biomass between trophic levels is inefficient and the cumulative biomass is reduced at each stage

A

because living organisms use some of the energy for physiological processes so it is lost as heat. The gross production of organic matter by autotrophic producers is only 1-3% of the solar energy because most is reflected, some is used to sustain the photosynthetic reactions, and other factors such as water availability limit the rate of photosynthesis

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14
Q

what biomass is lost in the transfer in between primary consumers from producers

A

lost in dead plant matter and parts of the plant not eaten

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15
Q

how much of the net production is passed to the next trophic level

A

only 5-10% of the net production is passed to the next trophic level

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16
Q

what do ecologists use to represent individual food chains or entire ecosystems

A

pyramids

17
Q

what does each bar in the pyramid represent

A

area of each bar is proportional to the number of individuals or as an approximation of total biomass at that level

18
Q

how is biomass transfers measured

A

comparing the dry biomass at one trophic level, by dividing it by the dry biomass at the lower trophic level

19
Q
A