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IB biology sl > unit 4 > Flashcards

unit 4 Flashcards

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1
Q

define species

A
  • a group of organisms that can interbreed to produce fertile offspring.

members of the same species have:

  • similar characteristics
  • different gene pools to other organisms
  • a common phylogeny
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2
Q

define habitat

A

the environment in which a species normally lives or the location of a living organism.

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3
Q

define population

A

a group of organisms of the same species who live in the same area at the same time

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4
Q

define community

A

a group of interdependent organisms inhabiting the same region and interacting with each other

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5
Q

define ecosystem

A

a community of organisms and the abiotic environment where they live.

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6
Q

define ecology

A

the study of relationships between living organisms and their environment.

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7
Q

what is an autotroph?

A
  • an organism that synthesizes its organic molecules from simple inorganic substances
  • plants and algae are mostly autotrophic but some are not
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8
Q

what is a heterotroph

A
  • an organism that obtains organic molecules from other organisms
  • consumers, detritivores and saprotrophs
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9
Q

what is a consumer and what are the different types?

A
  • heterotrophs that obtain their organic nutrients by ingesting living organisms
  • herbivore = feeds on producers (plants)
  • carnivore = feeds on other consumers (animals)
  • omnivore = feeds on a combination of both
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10
Q

what is a detrivore?

A
  • heterotrophs that obtain organic nutrients from detritus (non-living organic matter) by internal digestion
  • e.g earthworm
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11
Q

what is a saprotroph

A
  • heterotrophs that obtain organic nutrients from dead organisms by external digestion
  • because saprotrophs facilitate the breakdown of organic material, they are referred to as decomposers.
  • e.g bacteria and fungi
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12
Q

what are biotic factors?

A
  • living things (in an ecosystem)

- e.g. plants, animals, bacteria & fungi

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13
Q

what are abiotic factors

A
  • non-living things (in an ecosystem)

- e.g. temp, wind, moisture, sunlight & soil pH

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14
Q

what are the 3 requirements for sustainability in an ecosystem?

A
  • nutrient availability (nutrients can be recycled indefinitely)
  • detoxification of waste products
  • energy availability (energy cannot be recycled = sustainability depends on continued energy supply)
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15
Q

what is a decomposer?

A
  • organisms that derive energy from non-living organic matter
  • detrivores & saprotrophs
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16
Q

what is the nutrient cycle

A
  1. autotrophs convert nutrients from inorganic to organic molecules (e.g. carbon - glucose)
  2. heterotrophs ingest other organisms to gain organic forms of nutrients
  3. saprotrophs break down organic nutrients to gain energy - in the process, release nutrients back into inorganic molecules (e.g. fungi release nitrogen as ammonia into soil)
  4. this ensures the continuing availability of nutrients to autotrophs
17
Q

what is a mesocosm?

A

a biological system that contain the biotic and abiotic features of an ecosystem, but are restricted in size and/or under controlled condidtions

18
Q

what is a food chain?

A

shows the direction of energy flow from one species to another. The arrow indicates the direction of the energy flow

19
Q

what is a trophic level?

A

the trophic level of an organism is its position in the food chain

e.g. producers, primary consumers, secondary consumers and tertiary consumers

20
Q

what is a food web?

A

a diagram that shows all the feeding relationships in a community with arrows which show the direction of the energy flow

21
Q

what is a producer?

A

an organism which produces its own food through photosynthesis

22
Q

how do autotrophs obtain CO2

A
  • CO2 diffuses down the concentration gradient from the atmosphere or water into autotrophs (via stomata)
  • autotrophs convert CO2 into carbon compounds (e.g. carbs) by photosynthesis
23
Q

how is CO2 produced?

A
  • cellular respiration
  • methane oxidation
  • combustion of biomass and fossilized organic matter
24
Q

how does cellular respiration produce CO2?

A
  • during cell respiration, water & CO2 are created as byproducts
  • CO2 diffuses out of organisms into water or the atmosphere
25
Q

how does methane oxidation produce CO2?

A
  • methane is produced as a byproduct from organic matter in anaerobic conditions by methanogenic archaeans
  • methanogens are found in a variety of anoxic environments (e.g. wetlands & digestive tracts of animals)
  • some of the methane produced diffuses into the atmosphere or accumulates in the ground.
  • methane is oxidized to carbon dioxide and water in the atmosphere.
26
Q

how is peat formed

A
  • saprotrophs partially decompose dead organic matter. - dead organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils.
  • large quantities of partially composed dead organic matter build up.
  • the dead organic matter is compressed to form peat.
27
Q

annual fluctuations of CO2

A
  • during summer: the rate of photosynthesis /\ and therefore atmospheric CO2 concentration \/
  • during winter: plants lose their leaves and the rate of photosynthesis \/, therefore atmospheric CO2 concentration /\
28
Q

what are the greenhouse gasses?

A
  • CO2
  • water vapour
  • methane
  • nitrogen oxides
29
Q

what does the impact of a gas depend on?

A
  • its ability to absorb longwave radiation

- its concentration in the atmosphere

30
Q

how does the greenhouse effect happen?

A
  1. the incoming radiation from the sun is SW ultraviolet and visible radiation.
  2. some of this radiation is absorbed by the earth’s atmosphere = the warmed Earth emits LW radiation (heat).
  3. LW radiation is absorbed by gg that retains the heat in the atmosphere - also re-emits it back towards the earth.
  4. this causes the greenhouse effect and results in an /\ in average temperatures
  5. a rise in gg results in an /\ of the greenhouse effect which /\ the earth temperature further and this can be disastrous for the planet.
31
Q

what are the causes of the greenhouse effect?

A
  • /\ in CO2 (cause by deforestation & combustion of fossilized organic matter)
  • intensified animal farming
  • increased production of nitrogen oxides
32
Q

what are the effects of the greenhouse effect?

A
  • global warming
  • extinction of species
  • rising sea level

IB biology sl (6 decks)

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