Midterm 1.2 Flashcards

1
Q

Epigenetics

A

Study of heritable changes in gene expression

Involves phenotype: no changes in actual dna sequence

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2
Q

Anthropocene

A

Human era today
Damage to earth by human activity
Our impact: higher conc of greenhouse gases
Altered climate, etc

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3
Q

Carbon cycle

A

Organisms, volcanoes, natural processes pump CO2 in air
But humans adding a lot more to atm

Routes that C atoms take through env

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4
Q

Carbon placement

A
What phase/chemical bond 
#or carbon stays same
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5
Q

Carbon cycle problems with human int

A

Rate at which we extract carbon is exceeding natures capacity to return it/ absorb it
Dissolves in water, causes impacts

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6
Q

Phosphorus cycle

A

Phosphate is need for plants to grow
Agriculture: demand for phosphorus inc fast
Mining of phosphate rock for agr and fertilizers

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7
Q

Problem of human int of phosphorus cycle

A

Phosphates from fertilizers leak into our waterways and cause eutrophication
Boasts algae growth

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8
Q

Eutrophication

A

Excess phosphorus/nitrogen to soil drains into waterways and inc algae growth
Ex. Lake Winnipeg

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9
Q

Nitrogen cycle

A

Nitrogen passes from air (through lightning or bacteria) to NH4 that can be used by plants and animals

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10
Q

Industrial nitrogren fixation

A

The process of converting n2 from air to nh4 by haber process to make liquid ammonia which is a compound in fertilizers

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11
Q

Nitrogen cycle problems with human int

A

Fertilizers runoff and excess nitrogen boosts growth of plants and algae
Results in hypoxia and eutrophication, robbing the other organisms of oxygen

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12
Q

Implications of human modifications to cycles

A

Rate of modification is exceeding natures capacity
Disrupting cycles that are billions of years old
Ethical debate: we must feed and power ourselves too

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13
Q

Externalizing costs

A

A cost/ benefits that impacts something other than the buyer/seller.

Ex. Harm to citizens from water pollution, air pollution, etc.

We are externalizing costs to the environment

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14
Q

Interdependance of species example- wolves

A

Wolves brought dear pop down by hunting- also changed beh of deer who no longer went in the open prairies to graze all the grass- vegetation started to grow back- made habitats for other species- number of species increased (beavers, otters, ducks, mice, invertibraes)- more food for species and so on…rivers: less erosion with regenerating forests

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15
Q

Possible causes of extinction

A
Disease
Habitat destruction
Exploitation
Pollution
Pesticide use
Alien species
Uv radiation
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16
Q

Changes in pop

A

of organisms not stable
Fluctuations with env
Shifts may be dramatic

17
Q

J curve

A

Exponential growth:
Env conditions
Little competition
Exceeds carrying capacity

Over grazes and crashes due to starvation

18
Q

S curve

A

Pop increases but stabilizes around carrying capacity
Pop held in balance despite small fluctuations
Logistic curve

19
Q

Biotic potential

A

Capacity for a species to increase its numbers

Given optimum conditions, reproduction, expansion of habitat, etc

20
Q

Environmental resistance

A

Sum of factors that limit biotic potential
Geographically and biologically

Water, space, food, predators, disease

21
Q

Carrying capacity

A

Upper limit of # of organisms an ecosystem can support
Over long term
Includes both biotic pot and env resistance

22
Q

Critical number

A

Lowest number of org required to ensure that a pop may reproduce and continue

23
Q

Factors that influence pop #s

A
Available habitat
Availability of forage or prey (food)
Predation - capacity to kill prey
Disease
Parasites
24
Q

Keystone species

A

Species that has a large effect on community
Critical to functioning of ecosys
Disproportionately large effect relative to its abundance
On lower trophic levels or high ones
Keep things in check
When u remove, one pop may boom and the other may decline

25
Regime shift
Disturbance exceeds limit of ecosystem resilience Sudden Ex. Coral reef to algae reef Tropical forest to grassland
26
Forest fires
Crucial to some ecosys | Serotinous cones: seeds are only released when heated