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Rachel D Biology 2023 > Populations > Flashcards

Populations Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Define ecology

A

The study of the relationships between living organisms, including humans, and their physical environment.

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2
Q

Define ecosystem

A

A balanced biological system where all the organisms (community) and the non-living components interact in a particular location. There is energy flow and nutrient cycling within the ecosystem.

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3
Q

Define community

A

Interacting populations of two or more species in the same habitat at the same time.

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4
Q

Define habitat

A

The place where an organism lives.

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5
Q

Define population

A

A group of organisms of a single species, interbreeding and occupying a particular habitat.

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6
Q

Define environment

A

The factors in a habitat which affect an organism - both living (biotic) and non-living (abiotic).

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7
Q

Define niche

A

The role and position of an organism within its environment, including all interaction with the biotic and abiotic factors of its environment.

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8
Q

When will population size increase? (equation)

A

reproduction + immigration are greater than deaths + emigration.

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9
Q

List the four stages of a population growth curve

A

Lag, log/exponential, stationary, death/decline

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10
Q

What is carrying capacity?

A

The maximum number of individuals a habitat/environment can sustain

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11
Q

What causes the lag phase in a bacterial fermenter?

A

Enzymes are being synthesised

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12
Q

What could cause the death phase in a bacterial fermenter?

A

Accumulation of toxic waste, or resources run out (glucose or O2)

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13
Q

Define a density dependent factor

A

A factor that affects population size and is affected by population size

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14
Q

Define a density independent factor

A

A factor that affects population size and is not affected by population size

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15
Q

What is the ultimate source of energy for most ecosystems?

A

The sun

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16
Q

What is the difference between inter and intraspecific competition?

A

Inter is between species, intra is within one species

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17
Q

Why is photosynthetic efficiency not 100?

A

Sunlight misses the leaves, is transmitted, is reflected, is the wrong wavelength, is not absorbed by the chloroplasts.

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18
Q

Give the assumptions made during capture mark recapture (Lincoln Index)

A

No migration, birth or death, marked individuals distribute themselves evenly, the marking does not increase likelihood of death from predators and is not toxic

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19
Q

Define GPP

A

Gross Primary Productivity is is the rate of production of chemical energy in organic molecules by photosynthesis in a given area. The unit is kJ m-2 year-1

20
Q

Define NPP

A

NPP (kJ m-2) = GPP - energy used by plants in respiration. This is the energy available to primary consumers

21
Q

Why is energy lost between trophic levels?

A

Some tissues are not eaten or are indigestible (egested), energy is lost in respiration and excretory products

22
Q

Why are carnivores more efficient than herbivores?

A

Meat contains protein and fat, which are easier to digest than plant material

23
Q

How do you calculate the efficiency of energy transfer between trophic levels?

A

Energy in biomass after transfer/energy available before transfer x 100

24
Q

Define primary succession

A

Succession in a habitat that has never before been colonised. Bare rock- no soil/seeds/humus present

25
Q

Define secondary succession

A

The reintroduction of organisms into an area that was previously colonised. Soil, seeds and humus are already present

26
Q

The first plants to grow in a new habitat during succession are called?

A

Pioneer species

27
Q

What are the stages in succession called?

A

Seral stages/seres

28
Q

What is the climax community?

A

The final stable collection of plants and animals that succession produces. Equilibrium has been reached

29
Q

List the five key processes by which carbon moves through the carbon cycle

A

Photosynthesis, respiration, combustion, decomposition, fossilisation

30
Q

What is a carbon footprint?

A

The equivalent amount of CO2 generated by an individual a product or a service in a year.

31
Q

What do plants need nitrogen for?

A

Synthesising amino acids, nucleic acids and chlorophyll

32
Q

Give two forms of nitrogen that plants can take up

A

NO3- NO2- NH4+(nitrate, nitrite, ammonium)

33
Q

Name the process that converts atmospheric nitrogen to ammonium or nitrate

A

Nitrogen fixation

34
Q

What process can fix atmospheric nitrogen to form nitrate?

A

Lightning

35
Q

Name the two bacteria that perform nitrogen fixation

A

Azotobacter (free living) Rhizobium (root nodules of legumes)

36
Q

Name the process that converts ammonium to nitrate

A

Nitrification

37
Q

Which bacterium converts ammonium to nitrite?

A

Nitrosomonas

38
Q

Which bacterium converts nitrite to nitrate?

A

Nitrobacter

39
Q

Name the process that returns nitrate to atmospheric nitrogen

A

Denitrification

40
Q

Which bacterium performs denitrification and where is it found?

A

Pseudomonas and waterlogged soil/anaerobic conditions

41
Q

List the steps in eutrophication

A

Leaching of fertilisers into water, algal bloom, plants/algae die, bacteria decompose them and use up O2, animals die

42
Q

What is the effect of ploughing on soil?

A

Ploughing aerates the soil, increasing nitrification and decreasing denitrification

43
Q

What does a t test show?

A

If there is a significant difference between the means of two sets of data

44
Q

What is the null hypothesis of a t test?

A

There is no significant difference between the means of two sets of data

45
Q

When would you reject the null hypothesis of a t test?

A

When the t value calculated is above the critical value found in the probability table for the correct degrees of freedom

Rachel D Biology 2023 (23 decks)

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