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BIOL 2322 Ecology > Lecture 1: Physical Environments > Flashcards

Lecture 1: Physical Environments Flashcards

1
Q

Define ecology

A

the scientific study of the interactions that determine the distribution and abundance of organisms

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2
Q

Define distribution

A

the location in space or the geographic range of a species

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3
Q

Define abundance

A

the number of individuals and their density in space and time

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4
Q

Define abiotic factors

A

the non-living components of the environment; the physical and chemical conditions that contribute to the distribution and abundance of organisms

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5
Q

What are 7 examples of abiotic factors?

A
  1. TEMPERATURE
  2. WATER
  3. nutrient availability
  4. oxygen availability
  5. salinity
  6. pH
  7. light
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6
Q

Define biotic factors

A

The living components of the environment that contribute to the distribution and abundance of organisms

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7
Q

What are 5 examples of biotic factors?

A
  1. dispersal ability
  2. behaviour
  3. predation
  4. competition
  5. parasitism and disease
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8
Q

Define habitat

A

the physical place in which an organism lives

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9
Q

Define niche

A

the range of abiotic and biotic conditions which an organism can tolerate

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10
Q

T or F: many species can occupy both the same habitat and the same niche

A

FALSE.

Many organisms can occupy the same habitat, but no two organisms can occupy the same niche. One will become extinct or adapt.

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11
Q

Define organism

A

the individual that lives within a population. It acquires nutrients and produces wastes and has a boundary that separates internal processes from the environment

the basic unit of natural selection

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12
Q

Define population

A

a group of individuals from the same species that live and interact in the same area

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13
Q

Define species (in this class)

A

individuals that are capable of interbreeding and producing fertile, viable offspring

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14
Q

Define community

A

populations of different species that live and interact in the same area and time

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15
Q

Define ecosystem

A

one or more communities of living organisms interacting with their nonliving physical and chemical environments

ex. nutrient cycling

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16
Q

Define biome

A

a geographic region with communities of organisms with similar adaptations

ex. deserts, rainforests

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17
Q

Define biosphere

A

all the ecosystems on earth

distant ecosystems are linked together by wind and water exchanges and movements of organisms

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18
Q

What is the hierarchy of ecological systems?

A

organism < population < community < ecosystem < biome < biosphere

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19
Q

What is the key field of research involved in studying organisms? Describe it

A

Individual approach

looks at the connection between physiology, behaviour and an organism’s environment
tends to focus on adaptations

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20
Q

What is the key field of research involved in studying populations? Describe it

A

Population approach

studies the variations in the abundance, density and composition (genetic, sex ratio, age) of groups of individuals over space and time

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21
Q

What is the key field of research involved in studying communities? Describe it

A

Community approach

studies how interactions between species promotes or limits their coexistence

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22
Q

What is the key field of research involved in studying ecosystems? Describe it

A

Ecosystem approach

studies the flow of energy and cycling of matter (ex. carbon, nitrogen, and phosphorous) between physical and biological components

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23
Q

What is the key field of research involved in studying the biosphere? Describe it

A

Biosphere approach

studies the movements of air and water across Earth’s surface and how it impacts all other levels of the hierarchy

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24
Q

What are the three key thermal properties of water?

A
  1. resistance to temperature change
  2. resistance to phase changes
  3. density is affected by temperature
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25
Q

Describe why water is able to resist changes in temperature

A

water has a very high specific heat capacity which means it requires a lot of energy to raise the temperature even by 1 degree C. This is due to the hydrogen bonds that form water molecules. They require a lot of energy to break and reform.

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26
Q

Describe why water is able to resist phase changes (liquid, solid, gaseous)

A

water molecules are made up of hydrogen bonds between the partially negative oxygen molecule and 2 partially positive hydrogen molecules so it is very polar. This means the bonds require a lot of energy to break

27
Q

Describe how the density of water changes with temperature

A

Water is less dense as a solid than it is as a liquid

Density of water is highest at 4 degrees C

higher temperatures = less dense because the molecules are moving faster so the H-bonds break and reform at a faster rate

lower temperatures = less dense because the molecules are moving slower and stretch out around the H-bonds to form a crystal lattice and prevent the bonds from breaking and reforming

28
Q

Explain how the density of water results in a favourable environment for life but also limits the form and function of life

A

For example, in the Arctic, the solid water (ice) is less dense than the liquid water, so it will float. The floating ice results in a terrestrial environment for Arctic animals like polar bears. The ice also acts as an insulator for the body of water underneath so that an aquatic habitat can be maintained year round in a stable temperature.

Limits organisms’ ability to move through the water column - ability is dependent on their body density in relation to the density of water
- many aquatic organisms can adjust their density to maintain position or move through the water column

29
Q

Explain how the viscosity of water results in a favourable environment for life but also limits the form and function of life

A

viscosity of water creates friction while an organism moves through the water column and makes it so that movement requires much more energy and is much slower

organisms have to compensate for this by having streamlined body shapes to reduce drag and methods to do gas exchange like countercurrent gas exchange.

30
Q

Explain the importance of hydrogen ions in water

A

H+ ions are extremely reactive and can dissolve minerals from rocks and soils which is crucial for releasing otherwise trapped minerals required by organisms

31
Q

What pH range is acidic, neutral, and basic

A 
<7 = acidic
7 = neutral
>7 = basic
32
Q

What 3 elements do organisms require in the greatest quantities?

A

hydrogen
oxygen
carbon

33
Q

What are the other 8 elements organisms also require?

A
  1. nitrogen
  2. phosphorous
  3. calcium
  4. iron
  5. magnesium
  6. sulfur
  7. potassium
  8. sodium
34
Q

How does the particulate composition of soil affect its ability to provide dissolved nutrients and oxygen to plants?

A

Nutrients in the soil are usually in dissolved in an aqueous solution and the composition of the soil particles determines how well the soil can retain or drain water and the dissolved nutrients.

Soils with larger particulates like sand will drain more quickly and lose nutrients easier but will have more air space and more available oxygen

Soils with smaller particulates like clay will drain slower and hold onto nutrients easier, but will have less air space and less available oxygen

35
Q

What is the best soil type for plant productivity?

A

Loam: a combination of 40-50% sand, 30-40% silt, and 20% clay

36
Q

Why can oxygen availability be an issue in aquatic environments?

A

The dissolved oxygen content is much lower in water than it is in the air - 1% to 21% in air

Oxygen also diffuses much slower in water due to the viscosity and density of water so it requires more energy for oxygen to move from water into the systems of aquatic organisms

37
Q

How is oxygen availability in aquatic environments affected by temperature?

A

dissolved oxygen content is INVERSELY related to temperature

As temperature increases, dissolved oxygen content will decrease

ex. tide pools experience this dramatically

38
Q

Describe some adaptations in plants that help them overcome the low oxygen content of aquatic environments?

A
  1. aerenchyma: many root cells die and form air filled tubes that are better suited for oxygen transport
  2. pneumatophore: above ground extensions of root tissues filled with aerenchyma that enhance the ability of plants in swampy soils to access air
  3. adventitious roots: roots that grow above the surface of the soil to take advantage of the oxygen content in the air
39
Q

Describe some adaptations in animals that help them overcome the low oxygen content of aquatic environments?

A

Countercurrent gas exchange: maximizes oxygen uptake by having blood flow in opposite directions

Keeps oxygen constantly moving from water into the blood stream and from CO2 in the blood back into water

40
Q

Why is CO2 usually less available to plants in aquatic environments than in terrestrial environments?

A

CO2 is a large molecule so diffusion into aquatic plants is a very slow and energetically intensive process

aquatic organisms also are surrounded by a boundary layer which slows down diffusion of large molecules even more

41
Q

What is the primary source of carbon in aquatic environments?

A

Bicarbonate (HCO3)

An even larger molecule than CO2

42
Q

Describe osmoregulatory issues experienced by aquatic organisms in saltwater conditions and provide examples of adaptations to overcome these challenges

A

there is a lower salt concentration in the organism than in its surroundings so water will move out of the organism by osmosis (water moves from low solute concentration to high)

Adaptation: balance the loss by drinking saltwater and producing very concentrated urine with little water

Solutes will diffuse into the fish due to the concentration gradient (solutes move from high to low)

Adaptation: solutes diffuse across skin, lungs, and gills

43
Q

Describe examples of adaptations in plants that allow them to survive in hot environments

A

In hot temperatures, plants are vulnerable to desiccation

they will close their stomata when soil dries up

stomatal pits: the air in the pits can be kept moist due to trichome hairs to prevent water loss and allow stomata to remain open

trichome hairs: reflect direct sunlight from plant surface and trap moisture

reduced surface area of leaves and photosynthesis instead occurs in the chloroplast containing cells of the stem

44
Q

Describe examples of adaptations in plants that allow them to survive in cold environments

A
  • seasonally drop leaves to reduce vulnerable tissue
  • concentrate organic compounds in tissues to lower freezing temperature
  • produce antifreeze proteins to prevent ice crystal formation in cells
45
Q

What are some examples of how marine organisms excrete salt?

A

Animals have specialized salt glands
- ex. marine Iguanas

plants: take in saltwater and concentrate organic molecules in their roots to create higher solute solution in the tissues compared to the salt water so that water will flow from their surroundings into their roots

46
Q

Describe examples of adaptations in animals that allow them to survive in hot environments

A

temperate animals have veins in the extremities that are farther apart and closer to the surface

as blood travels out to extremities, it cools and as it returns to torso, it is much cooler than it was going out

47
Q

Describe examples of adaptations in animals that allow them to survive in cold environments

A 
SOME animals (like frogs) can: 
- concentrate organic compounds in tissues to lower freezing temperature
  • produce antifreeze proteins to prevent ice crystal formation in cells

Others:

  • countercurrent heat exchange: veins are arranged close together and close to arteries (away from surface) in extremities (limbs) to reduce heat loss to surroundings
  • fur, fat, feathers reduce heat loss
  • thermal inertia: resistance to temperature change with large body volume - increased surface area to volume ratio = helps with insulation
48
Q

Describe examples of adaptations in animals that allow them to survive in variable environments

A

Seasonal fluctuations can be a real issue for aquatic animals life fish so they can acclimate to gradual changes in temperature by using different enzymes that function better in different temperatures

49
Q

Describe ectotherms and give an example

A

animals with an internal body temperature that matches the external environment and will fluctuate as the environment fluctuates

ex. reptiles

50
Q

Describe endotherms and give an example

A

animals with an internal body temperature that is constant and maintained at a different temperature than the external environment

ex. mammals

51
Q

Describe the photosynthetically active region of the electromagnetic spectrum

A

the visible light part of the electromagnetic spectrum that is used by photosynthetic organisms (400nm-700nm)

52
Q

What factors impact the availability of visible light to plants in terrestrial environments?

A

shading by other plants reduces light availability under forest canopies

Canopies have the most light but as you move down through the plant growth levels, less and less light will filter through until there’s mostly shade on the forest floor

53
Q

What factors impact the availability of visible light to photosynthetic organisms in aquatic environments?

A

Most light reflects directly off the water surface so there’s already not much light actually penetrating into the photic zone

Then most of the light that does penetrate into the photic zone is absorbed by photosynthetic organisms and other particles in the water, so less light will be able to penetrate deeper

54
Q

Which colours of light are most important in providing energy for photosynthesis of terrestrial plants?

A

Chlorophyll a (major pigment): absorbs blue and red wavelengths

chlorophyll b: absorbs blue and orange wavelengths

carotenoids: absorb more blue-green and yellow

55
Q

In water, which colour (and wavelength) penetrate the deepest? Why?

A

Blue because light quality changes with depth and not all pigments are absorbed in the same amount as you move down the water column

this is also due to the fact that not much light penetrates deeper than 200m

56
Q

What is homeothermy?

A

temperature regulation that endotherms use via a negative feedback loop

57
Q

Describe dispersal ability and how it’s a biotic factor

A

characteristics of a species itself that limit its dispersal

ex. an animal that can walk, run, swim, or fly better than others will be able to disperse further
ex. a tree that has a better ability to more widely disperse seeds

58
Q

Describe how behaviour can be a biotic factor

A

animals can look for specific cues in habitats when selecting where to be

59
Q

How do hummingbirds regulate their temperature?

A

by increasing metabolic rate

lower air temperature = higher metabolic rate, especially when active

as air temp. increases, their metabolism can drop because they won’t need to consume as much oxygen to maintain their internal temperature

torpid: temporary hibernation state done at night to slow down metabolism

60
Q

List 2 advantages and 2 disadvantages of ectothermy

A

ADV:

  1. lower metabolic requirements allow organisms to live where food or oxygen is less available
  2. can withstand more environmental fluctuations

DIS:

  1. do not do as well in extreme temperatures
  2. there is an upper limit on body size due to efficiency of heat exchange so they tend to be smaller organisms
61
Q

List 2 advantages and 2 disadvantages of endothermy

A

ADV:

  1. less effected by external temperatures so metabolic rates can be increased to maintain internal temperature
  2. can survive and reproduce in much more extreme climates

DIS:

  1. very energetically expensive to maintain a constant internal temperature = requires much more food and oxygen
  2. there is a lower limit on body size due to the surface area: volume ratio = larger organisms don’t tend to lose heat as quickly as smaller organisms
62
Q

T or F: light is the primary source of energy for the biosphere - why/why not?

A

TRUE because of photosynthesis

63
Q

Describe the photic zone of aquatic environments

A

the top 200m of the water column where light penetrates

the zone where photosynthetic organisms occupy

BIOL 2322 Ecology (13 decks)

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