lec 14

Question 1

Terrestrial abiotic factors which shape diversity

Answer 1

Sunlight,
Temperature,
Precipitation,
Nutrients,
wind,
latitude,
altitude,
soil type

Question 2

Aquatic abiotic factors which shape diversity

Answer 2

Light (Penetration)
Water temperature
Nutrients
Water Currents
Salinity
Nutrients

Question 3

Most important factor in organism distribution _____
It has a significant effect on _______
But this is complicated because

Answer 3

Temperature
Biological factors
Most organisms can not regulate their body temperature

Question 4

Smaller animals must _________ to maintain their body temperature

Answer 4

spend more energy

Question 5

Large animals body temperature is ________

Answer 5

slower to change

Question 6

Reef-building corals require warm water conditions to survive. Different corals living in different regions can withstand various ________ ________

Answer 6

Temperature fluctuations

Question 7

Coral reefs have the greatest biodiversity within

Answer 7

within the seas and perhaps the Earth

Question 8

Many corals consist of a symbiotic association made up of an invertebrate animal and algae
This symbiosis is ____ ______

Answer 8

light dependent

and part of the reason we see coral declines in warming waters is the impact of turbidity on the algae

Question 9

In aquatic environments, water absorbs light preventing photosynthesis at depths greater than

Answer 9

100m (photic zone)

Question 10

The photic zone value is not _____ and fluctuates with turbidity and biological activity

Answer 10

static

Question 11

As light penetrates water different wavelengths are

Answer 11

lost before others

Question 12

Abiotic factors that affect diversity- salinity

Answer 12

Aquatic organisms must maintain osmotic balance (i.e. keep internal salt levels constant)

Question 13

Freshwater fish are hypertonic and tend to

Answer 13

gain water and have to constantly eliminate water

Question 14

Marine fish are hypotonic and tend to

Answer 14

lose water to the environment and must drink water to compensate

Question 15

There is a strong relationship between terrestrial systems relating to temperature and precipitation

Answer 15

With low precip and low temps you get tundra
Low precip and high temps results in deserts
High precip and high temps result in rainforest
Strangely we have no niches containing high precip and cold temperatures

Question 16

The full collection of environmental variables come together to form Biomes which are

Answer 16

regions of homogenous structure

Question 17

Tropical forests: light and nutrients are in high demand. They have

Answer 17

A thick canopy blocks light to bottom strata, in response many trees are covered by epiphytes, or, can survive with low light
Species richness: extremely high
Tree species > 100/km2
Large mammals are less common though birds and ectotherms abound

Question 18

One of the largest terrestrial biomes on Earth is the taiga (Boreal forest). It has

Answer 18

Moderate moisture and long cold winters
Species richness: is relatively low but varies season to season
Ectotherm diversity such as amphibians and reptiles are low

Question 19

Grasslands occur where the moisture is too low to support forests. They have

Answer 19

Inter-continental climate (cold winters, hot summers)
Marked by seasonal drought and fires, and grazing by large animals
Species richness: plants (fairly high), animals (relatively low)
Soil very rich in nutrients
Considered the most endangered biome worldwide (1% of North American prairie left)

Question 20

Tundra or permafrost (Permanent frozen ground) are bitterly cold, have high winds, low moisture, no trees, short growing season. It

Answer 20

Covers 20% of land surface on earth
Low species richness (animals and plants)
Fauna much richer in summer (migratory birds)

Question 21

Deserts are defined by lack of moisture. They have

Answer 21

Plants and animals have adapted for water storage and conservation
They Can be either very hot, or very cold (e.g. Antarctica)
Moderate to very low species richness

Question 22

Aquatic biomes cover 75% of the earth’s surface, they contain

Answer 22

the majority of living space (>90%)

Question 23

Freshwater in northern climates go through annual cycles

In early SPRING water is 4 degrees Celsius from top to bottom

Answer 23

Density of water is uniform from top to bottom as is the oxygen distribution

Question 24

As atmospheric temperatures warm in the SUMMER, _______ _______ sets in from heating of the surface waters

Answer 24

thermal stratification

Question 25

Temperature differences in water column create different water densities

Answer 25

Lighter warm surface water floats on denser deep cold waters

Deep waters remain cold all summer; do not mix with warm surface water
Oxygen is now higher at the surface and low at depth

Question 26

Zone between warm and cold water is the

Answer 26

thermocline

Question 27

As FALL sets in heat declines, surface waters cool, density gradients are lost

Answer 27

Water column mixes top to bottom again as in spring
Barriers are eroded and deeper waters become re-oxygenated
Water column reaches a uniform temp of 4 degrees Celsius again
Ice forms at surface as water cools to 0 degrees Celsius

Question 28

In winter a unique property of water emerges which is to become very dense at ~4 degrees Celsius

Answer 28

An inverted temperature profile is established
Less dense ice forms at the surface as water continues to cool
Ice insulates and further cooling and ice formation stops
Water column again becomes thermally stratified

Question 29

Freshwater lakes can be divided into two types:

Answer 29

Oligotrophic lakes and Eutrophic lakes

Question 30

Oligotrophic lakes are

Answer 30

nutrient poor, water is clear, cool and oxygen rich; little productivity by algae, often have high diversity of fish

Question 31

Eutrophic lakes are

Answer 31

nutrient rich, lots of algal productivity, oxygen poor at times, high algal diversity, but low diversity of fish (winter/summer kill likely)

Question 32

Rivers are heavily affected by human activities; most large rivers are now _______ at multiple points along their length

Answer 32

dammed

Question 33

Benthic (bottom dwelling) algae and aquatic insects are a highly diverse group in rivers but sensitive to

Answer 33

changes in turbidity, temp and nutrient loading

Question 34

Wetlands includes marshes, bogs, swamps and seasonal ponds

These are habitats of high

Answer 34

biodiversity and productivity

Question 35

Many wetlands have been lost (>70% on Plains), resulting in

Answer 35

increased flooding; wetlands act as a natural reservoir capturing heavy rains and snow melt

Question 36

An estuary is

Answer 36

where freshwater stream or river merges with the ocean

Highly productive biome; with many euryhaline species, sensitive chemical balances at risk

Question 37

Estuaries depend on

Answer 37

a dynamic but predictable salt cycle which is easily disrupted by human activities

Question 38

the pelagic zone is at risk from

Answer 38

overfishing and pollution

Question 39

Mangroves are

Answer 39

very frost sensitive, and only found between latitudes 25oS and 25oN where wave action is minor

Question 40

Mangroves

Answer 40

cover 60-75% of tropical coastlines and support a rich fauna of birds in tree tops, and snails, barnacles, oysters, and crabs below

Question 41

Mangroves have sheltered waters around roots which

Answer 41

provide nursery habitat for organisms

Question 42

reef building corals require _______

But different corals

Answer 42

warm temperature conditions to survive