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Biology > D4 Continuity and Change of Ecosystems > Flashcards

D4 Continuity and Change of Ecosystems Flashcards

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1
Q

Polymorphic trait

definition

A

a trait that has more than 2 but less than 4 genetic variations (can eb at a phenotypic or genotypic level)

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2
Q

directional selection

definition

A

when a trait has two or 3 categorical phenotypes and natural selection favours one

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3
Q

stabalising selection

definition

A

when there is a continuum of phenotypes for a trait and natural selection favours the average not the extremes

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4
Q

disruptive selection

define

A

either extreme phenotypes are prefered to the average on a continuum of phenotypes for a trait (can be the begining of speciation)

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5
Q

genetic equalibrium

define

A

when there is no change in allele frequencies over time, usually in reference to one trait/gene

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6
Q

conditions needed for a population to be in genetic equalibrium

A
  1. large population size
  2. no immigration or emigration (gene flow)
  3. no favoured phenotype
  4. no sexual selection (random mating)
  5. no generation of new alleles that change the phenotype by mutation
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7
Q

ecosystem sustainability

define

A

the ecosystem can support itself without outside influences. Allowed when changes to an ecosystem are slow enough that organisms can still adapt to and thrive

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8
Q

tipping point

define

A

the point where an ecosystem has endured too much damage and can no longer be self-sufficient or sustained

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9
Q

requirements for an ecosystem to remain stable

A
  1. sufficient energy supply
  2. nutrient recycling
  3. enetic diversity
  4. good response to climate change
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10
Q

keystone species

define

A

a species that has a disproportunate effect on the ecosystem

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11
Q

trophic cascade

define

A

when a top predator is removed and consequently destabalises the lower trophic levels and ecosystem balance

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12
Q

soil erosion

define

A

the loss of nutrient rich topsoil by excess rain or wind

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13
Q

leaching

define

A

when rain or irrigation water disolves nutrients in the soil and pulls it down past plant roots so that they can’t be absorbed by roots

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14
Q

agrochemicals

define

A

chemicals like pesticides and fertilisers used by farmers, that lead to eutrophication and water pollution

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15
Q

carbon footprint

definition

A

the total amount of greenhouse gasses that is generated by an activity

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16
Q

tillage

definition

A

preperation of soil for crops that uses machinery that emitt carbon emissions

17
Q

eutrophication

definition

A

an abundance of nutrients running into water causing algae to overgrow on surface, increase in decomposers, decrease in oxygen, decrease in fish

18
Q

biochemical oxygen demand

definition

A

the amount of oxygen needed by bacteria decomposers in water to carry out cellular respiration

19
Q

biomagnification

definition

A

when there are traces of toxins in the water that get passed up trophic levels

20
Q

macroplasitcs

size

A

larger than 5mm

21
Q

microplastics

size

A

smaller than 5mm

22
Q

pioneer species

definition

A

the first species to exist in a newly established ecosystem

23
Q

climax community

definition

A

a stable point of peak biodiversity and population in an ecosystem

24
Q

cyclical succession

definition

A

when an ecosystem does not reach one stable climax community but many in a repeating cycle

25
Q

permafrost

definition

A

the soil in very cold climates below the surface that is frozen solid

26
Q

albedo

definition

A

the ability of a sureface to reflect light (dark object = low albedo)

27
Q

landfast ice

defintion

A

a frozen layer of seawater that is attached to the land, important in some organisms breed here

28
Q

ocean stratification

definition

A

the layers of the ocean where warmer less salty water floats on the top of the cold, nurtient dense layer

29
Q

carbon sequestration

definition

A

the capture and storage of carbon that can happen naturally or to combat climate change

30
Q

phenology

definition

A

the study of the timing of periodic events in living organisms

31
Q

photoperiod

definition

A

the number of hours a day when the sun is shining

32
Q

trophic mismatch

definition

A

when an abiotic change disrupts the annual cycle of a species, causing it to fcall out of sync with other species

33
Q

microevolution

definition

A

tracing changes over time in a syngle phenotypic trait (often using hardy weinburg)

34
Q

polymorphism

definition

A

when there are two or more phenotypes for a trait that are equally present and neither provides an advantage

Biology (12 decks)

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