Lecture Five

Question 1

How does temperature affect diversity (abiotic)?

Answer 1

Temperature is the most important factor in the distribution of organisms. Temperature has significant effects on biological processes (i.e. protein function, metabolism) and this is complicated by the fact that most organisms are not able to regulate body temperature precisely (ectotherms, though endothermic animals are still affected by temperature variation).

Question 2

How are Vampire Bats affected by temperature?

Answer 2

They are limited to areas where the average minimum temperature in January is above 10 degrees.

Question 3

Smaller or Larger: which animals spend more energy to maintain their body temperature?

Answer 3

Smaller.

Question 4

Smaller or Larger: which animal’s body is slower to react to temperature change?

Answer 4

Larger.

Question 5

How is Coral affected by temperature?

Answer 5

Reef-building corals require warm water conditions to survive. Different corals living in different regions can withstand various temperature fluctuations; however, typically they live in water between 20-32 degrees. Corals have great biodiversity and productivity with a symbiotic association between invertebrate animal and algae that is light dependent and the impact of turbidity (due to warm water) on algae is severe.

Question 6

How does light affect biodiversity (abiotic)?

Answer 6

In aquatic environments, water absorbs life preventing photosynthesis at depths greater than 100m (photic zone). As light penetrates water, different wavelengths are lost before others.

Question 7

What is the photic zone value?

Answer 7

The level at which light does nothing to help life. It is not static and fluctuates with turbidity and biological activity.

Question 8

Why do red algae occur at greater depths than green-blue algae?

Answer 8

Because they posses pigments that enable them to use blue-green light, a wavelength that penetrates water further.

Question 9

How does salinity affect biodiversity (abiotic)?

Answer 9

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

Question 10

How does salinity affect Freshwater fish?

Answer 10

Hypertonic, they tend to gain water and have to constantly eliminate water.

Question 11

How does salinity affect Marine fish?

Answer 11

Hypotonic, they lose water to the environment and must drink water to compensate.

Question 12

What abiotic factors affect the biodiversity of the aquatic environment?

Answer 12

Light (penetration)
Water temperature
Nutrients
Water Currents
Salinity
Water Chemistry

Question 13

What abiotic factors affect the biodiversity of the terrestrial environment?

Answer 13

Sunlight
Temperature
Precipitation
Nutrients
Wind
Latitude
Altitude
Soil type

Question 14

In Terrestrial environments, what occurs with low precipitation and low temperatures?

Answer 14

Tundra.

Question 15

In Terrestrial environments, what occurs with low precipitation and high temperatures?

Answer 15

Deserts.

Question 16

In Terrestrial environments, what occurs with high precipitation and high temperatures?

Answer 16

Rainforest.

Question 17

In Terrestrial environments, what occurs with high precipitation and low temperatures?

Answer 17

This isn’t an existing niche.

Question 18

What do the full collection of environmental variables comes together to form?

Answer 18

Biomes - homogenous regional structures.

Question 19

What is characteristic of a tropical forest?

Answer 19

Light and nutrients are in high demand. Thick canopy blocking light to bottom strata, many trees are covered by epiphytes (to catch more light – mooching growth of tree). Rainforest soil is very low in nutrients because the nutrients are locked in long-lived trees. Species richness: extremely high. Tree species > 100/km^2. Large mammals are less common, though birds and ectotherms are abound.

Question 20

What is characteristic of the Taiga (Boreal Forest)?

Answer 20

One of the largest terrestrial biomes on earth. Moderate moisture and long cold winters. Species richness: relatively low, but varies season to season. Ectotherms such as amphibians and reptiles are low.

Question 21

What is characteristic of the Grasslands?

Answer 21

Occur where the moisture is too low to support forests. Inter-continental climate (cold winters, hot summers). Marked by seasonal drought and fires, and grazing by large animals . Species richness: plants (fairly high), animals (fairly low), soil very rich in nutrients. Considered the most endangered biome worldwide (1% of North American prairie left).

Question 22

What is characteristic of the Tundra/Permafrost?

Answer 22

Permanent frozen ground. Bitterly cold, have high winds, low moisture, no trees, short growing season. Covers 20% of land surface on earth. Low species richness (animals and plants), fauna much richer in summer (migratory birds) because of 24 hour days – increased energy.

Question 23

What is characteristic of the Desert?

Answer 23

Defined by lack of moisture. Plants and animals have adapted for water storage and conservation . They can either be very hot, or very cold (E.g. Antarctica). Moderate to very low species richness.

Question 24

How much of the world do aquatic biomes cover?

Answer 24

75% of the earth’s surface and the majority of living space (>90%).

Question 25

What is the Freshwater cycle that northern climates go through?

Answer 25

Early spring: water = 4 degrees equally; uniform density of oxygen.
Summer: thermal stratification, warm top and cold bottom (between zone is called thermocline), oxygen higher at surface than deep.
Fall: temperature and density gradients lost. Ice forms at surface as temperature reaches 0.
Winter: very dense (at 4 degrees), inverted temperature profile - less dense ice forms at surface, ice insulates. Colder at top, more oxygen.

Question 26

What are Oligotrophic lakes?

Answer 26

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

Question 27

What are Eutrophic Lakes?

Answer 27

Freshwater lakes that are nutrient rich, lots of algal productivity, oxygen poor at times, high algal diversity, but low diversity of fish (winter kill likely).

Question 28

What is characteristic of Rivers?

Answer 28

Heavily affected by human activities; most large rivers are now dammed at multiple points along their length. Benthic (bottom dwelling) algae and aquatic insects are a highly diverse group in rivers but sensitive to changes in turbidity, temperature, and nutrient loading. Currently the WWF is conducting a health assessment of all of Canadian rivers to determine threats and neutralize as many possible in the coming decade.

Question 29

What is characteristic of Wetlands?

Answer 29

Include marshes, bogs, swamps, and seasonal ponds. These are habitats of high biodiversity and productivity. Many wetlands have been lost (>70% on Plains). The result of lost wetlands is increased flooding; wetlands act as a natural reservoir, capturing heavy rains and snow melt. In their absence, flooding becomes a significant issue across the prairies.

Question 30

What is characteristic of an Estuary?

Answer 30

Where freshwater stream or river merges with the ocean, it is a highly productive biome; with many euryhaline species. Given their proximity to the coast (and our own dependence on the coast), the sensitive chemical balance of estuaries is at risk. They depend on a dynamic but predicable salt cycle which is easily disrupted by human activities.

Question 31

What water zones are at risk from human activity?

Answer 31

Most of them - near shore habitats (estuaries, intertidal zones…) and pelagic zone (ocean wateR). The oceans offer the most stable conditions for life, unfortunately this has resulted in life forms that have minimal abilities to adapt and even small changes in temperature can change distributions and disrupt communities.

Question 32

What zone is likely in near pristine condition?

Answer 32

Abyssal zones - currently out of our reach.

Question 33

What are characteristic of Mangroves?

Answer 33

Very frost sensitive, and only found between latitudes 25S and 25N, where wave action is minor. They cover 60-75% of tropical coastlines. Support a rich fauna of birds in tree tops, and snails, barnacles, oysters, and crabs below. Sheltered waters around roots provide nursery habitat for organisms.