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BIO IB > Unit 8: Ecosystems - Stability, Change and Conservation > Flashcards

Unit 8: Ecosystems - Stability, Change and Conservation Flashcards

1
Q

what is evolution

A

change in the heritable characteristics of a population

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2
Q

what is lamarckism

A

acquired traits can be passed down to offspring
–> now FALSIFIED

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3
Q

evidence for evolution

A

DNA –> RNA –> Proteins

Evidence =
1. new sequences arise and some become more common
2. some genes are common to many species
3. genes in closely related species are more similar

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4
Q

evidence for evolution from selective breeding of domesticated animals and crop plants

A

(artificial selection) selective breeding –> domestication of crop plants and animals
—-> control reproduction, control offspring so that desirable traits become more common

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5
Q

evidence for evolution from homologous series

A

homologous series = same structure

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6
Q

what is a stable ecosystem

A

can persist for a very long period of time

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7
Q

what are the requirements for a stability in an ecosystem

A

stability depends on:
- nutrient cycling
- constant energy supply
- genetic variation within a species
- stable climate

disruptions include:
- removal of materials/species
- eutrophication
- climate change

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8
Q

what is a tipping point

A

reaching a level of disturbance that causes quick change that is difficult to reverse

(i.e. amazon rainforest: deforestation = fewer trees = less transpiration = drought
= fires)

positive feedback loop

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9
Q

what is a model that can be used to investigate the effect of variables on ecosystem stability

A

mesocosm

adv: replicates, easy, control factors
disadv: impossible to replicate all natural factors

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10
Q

what is a keystone species

A

an organism that has a disproportionate effect in a community (i.e. removal will make it likely that the entire ecosystem will collapse)

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11
Q

what is sustainable harvesting

A

replacement rate must be > or = to harvesting rate

i.e. cod
-> protected breeding zones
-> increase net hole size
-> set harvesting limits
-> monitor populations

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12
Q

what are the factors that affect the sustainability of agriculture

A

consider the following:
-> soil erosion (tilling causes soil loss)
-> fertilisers leach into bodies of water (causes eutrophication)
-> pollutants (pesticides)
-> carbon footprint (from energy/fuels)

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13
Q

explain eutrophication

A

nitrogen and phosphorus rich fertilisers on land run off into bodies of water

algae bloom on surface blocks sunlight and kills bottom plants

deecomposition of plants consumes all of the oxygen, increases biological oxygen demand, killing other marine life

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14
Q

explain biomagnification of pollutants in natural ecosystems

A

bioaccumulation - increase toxin levels throughout an organisms life

biomagnification - increase toxin levels throughout trophic levels
–> higher trophic levels higher toxin levels

toxin examples: mercury and DDT

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15
Q

what are the effects of microplastic and macroplastic pollution of the oceans

A

plastic waste accumulates because it doesn’t break down, can release toxic compounds

macroplastic = large visible waste
–> ingestion by marine life
–> entanglement

microplastic = small fragments from the degradation of large pieces
–> found EVERYWHERE
–> in animal tissues
–> effect TBD

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16
Q

what is rewilding and what does it do?

A

rewilding = remove effects of human intervention to allow natural processes to restore ecosystems

can do this by:
- stop human activities
- reintroduce species
- distributing seeds of plants that should occur there
- control invasive species
- reconnect habitats

example: Hinewai Reserve in NZ
shift from farmland to native forest by reducing effect of human intervention

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17
Q

describe ecological succession and its causes

A

ecological succession = biotic and abiotic changes that transform an ecosystem

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18
Q

what is primary succession

A

succession starting w an environment w few living organisms
(like bare rocks, bacteria, lichens cause erosion, soil development, shrubs, trees

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19
Q

what are the changes that happen during primary succession

A

increase in…
- primary production
- species diversity
- food web complexity
- nutrient cycling

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20
Q

what cyclical succession

A

patterns of change and succession that occur either naturally or due to periodic disturbances

i.e. = oak forest –> grassland –> oak forest

no stable climax community

21
Q

what is a climax community

A

a stable, relatively unchanging ecosystem

22
Q

what is a plagioclimax

A

alternative climax community that results from human activity

i.e.
grazing
-protected, artificially high population of livestock
-grasses persist
-no succession by shrubs or trees

wetland drainage
-swamps and bogs are natural carbon sinks
-waterlogged and anoxic, special adaptations
-drainage causes other plants to thrive

23
Q

what is arrested succession

A

ecosystem permanently halted in an early successional, typically non forested state

24
Q

normal vs enhanced greenhouse effect

A

normal = good
- keeps earth warm
enhanced = bad
- thickening of greenhouse gases-BADDD

25
Q

positive feedback cycles in global warming

A
  1. less snow –> less sunlight reflection –> more radiation absorbed –> more ice melting
  2. more heat –> more permafrost –> more decay and more methane
  3. warmer oceans –> less dissolved co2 –> more co2 in atmosphere –> more heat
  4. warmer temps –> more drought more fires –> more carbon release
26
Q

explain an example of polar habitat change

A

emperor penguins
use ice for breeding
distance to/from sea is important
early icebreak can kill chicks

walruses
use ice for resting
lack of ice –> energy expenditure finding ice

27
Q

explain how changes in ocean currents alter the timing and extent of nutrient upwelling

A

warmer surface water decreases ocean currents, leading to stratification (stable layers instead of mixing)

less current also leads to less upwelling of nutrients and altered timing, reducing nutrient cycling and primary production and energy flow

28
Q

explain poleward and upslope range shifts of temperate species

A

UPSLOPE
animals live at top of mountain
only them because niches
if warmer, species move upslope to find optimal temp
compete for niches with species already living up there

POLEWARD
same as before, but instead of up, they move to the poles

29
Q

what are the threats to coral reefs

A

co2 absorption causes water to become acidic
more difficult for corals to absorb carbon from water
calcium carbonate shells of marine organisms dissolve
warm water also causes coral to expel mutualistic algae (bleaching)
thus, coral reef ecosystem collapses

30
Q

what is carbon sequestration

A

capturing and storing carbon (making a carbon sink)

–> photosynthesis
–> plant growth
–> building of shells of marine organisms
–> fossilisation and peat formation

31
Q

what is afforestation

A

planting trees in areas w/ no trees

32
Q

what is forest regeneration

A

planting trees that have been cut down

33
Q

adv and disadv of afforestation/forest regeneration

A

usually fast growing species that do not occur naturally

adv:
positively affects carbon sequestration

disadv:
monoculture
may have neg. impacts on other factors that affect ecosystem stability

34
Q

describe peat forming wetlands restoration

A

peat = partially decomposed organic matter trapped under acidic, waterlogged soil (anoxic)

can happen quickly in tropical environments

restoring previously drained wetlands and reintroducing native species helps reestablish these areas as carbon sinks

35
Q

what is phenology

A

study of seasonal timing of event in plants and animals

changes in timing can indicate climate change

2 major factors: temp and photoperiod (daylight hours)

36
Q

what are some events affected by the 2 major factors of phenology

A

temp:
bud burst (new leaves)

photoperiodism
bud set (growth stoppage)
flowering (short day vs long day plants)
bird migration

37
Q

explain the disruption to the synchrony of phenological events by climate change

A

Temps are changing
Two interacting species need to synch their timing
if one is cued by photoperiods, and another by temps
a disruption in temp may throw off the timing of events necessary for successful interaction

i.e. caribou eat arctic mouse ear and time their spring migration to match the peak development of the arctic mouse ear
-mismatch between migration timing and plant development-> not enough food supply

i.e.2 great tit eat caterpillars
need lots of food during breeding season
caterpillar population peak earlier due to warmer weathers
great tit breeding season stayed the same
fewer surviving chicks

38
Q

explain the increases to the number of insect life cycles within a year due to climate change

A

spruce bark beetle (pest)
-develops in weak trees
-healthy trees limit spruce bark beetle population
-drought and warm temps stress trees
-more spruce bark beetles
2 year generation time has reduced to 1
trees are now more susceptible and there are more beetles

39
Q

explain evolution as a consequence of climate change

A

tawny owl
-overpopulation and competition = food shortage
-variation = feather colour (gray vs brown)
- survival of the fittest (less snow cover changes the ability to blend in)
- increase in trait frequency = brown colour more common

40
Q

what are the different types of diversity

A

ecosystem
varied environments and species (i.e desert vs coral reef)

species
many diff species (i.e. fungus vs polar bear)

genetic
gene pool within species vary (poodle vs great dane)

41
Q

now vs then: number of species on earth

A

many more now than then

42
Q

causes of anthropogenic species extinction

A
  1. overharvesting
  2. habitat destructions
  3. invasive species
  4. pollution
  5. global climate change
43
Q

causes of ecosystem loss

A
  1. land use for agriculture
  2. urbanisation
  3. overexploiting resources
  4. mining
  5. dams and water extraction
  6. diversion of water
  7. fertilisers and eutrophication
  8. climate change
44
Q

evidence for a biodiversity crisis

A

biodiversity crisis: unprecendented loss of ecosystems, species, and genetic diversity

  1. population sizes
  2. ranges
  3. species diversity in an ecosystem
  4. richness and evenness
  5. area
  6. degradation extent
    etc etc

simpson’s diversity index:
D = diversity index
N = total number of organisms in all species
n = total number of individuals in a specific species

D = (N(N-1))/(∑(n(n-1)))

high index when you have a high richness and evenness of species

45
Q

causes of the current biodiversity crisis

A

overpopulation

46
Q

need for several approaches to conservation of biodiversity

A

in situ: conservation in the natural environment
- no disruption to behaviour/evolution
-cost-effective
-active management

ex situ: outside the natural habitat
- captive breeding and release
- preservation of endangered species
- preservation of eggs/sperm/seeds

47
Q

selection of evolutionarily distinct and globally endangered species for conservation prioritisation in the EDGE of Existence programme

A

you cannot save them all

EDGE of existence prioritises conservation efforts based on
- uniqueness
- likelihood of extinction)

48
Q
A

BIO IB (12 decks)

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