Chapter 3: Environmental Conditions

Question 1

How do environmental conditions differ from environmental resources?

Answer 1

Environmental conditions are not consumed, used up or made more or less available to others like environmental resources.

Question 2

Define Homeotherm

Answer 2

organisms that maintain a constant body temperature

Question 3

Define Poikilotherm

Answer 3

Organisms that have body temperatures that vary passively with ambient temperature

Question 4

Define Ectotherm

Answer 4

Organisms that use external heat sources to regulate body temperature

Question 5

Define Endotherm

Answer 5

Organisms that use internally produced heat to regulate body temperature

Question 6

List the factors that influence the amount of solar radiation absorbed by an animal.

Answer 6

time of day, amount of dust in the atmosphere, clouds and color of an organism

Question 7

Under what conditions does thermal radiation flow into an animal’s body?

Answer 7

if the surroundings are warmer than the organism

Question 8

Define convection and comment on its importance for heat exchange in animals.

Answer 8

Convection is the heat transfer from an object to a fluid that surrounds it. This is important because animals can spread out or curl up depending on what they want their temperature to be.

Question 9

What parameters determine the direction and effectiveness of convectional heat exchange between an animal and its surroundings?

Answer 9

Temperature of the animal and its surroundings, the shape of the animal and the wind speed

Question 10

How might an animal modify the amount of heat lost or gained by convection?

Answer 10

by changing its body shape by spreading out or curling up in a ball

Question 11

What is conduction and how might an animal exchange heat by conduction?

Answer 11

Conduction is heat exchange through physical contact between the animal and its substrate ie; by pressing its body to a warm surface

Question 12

How do animals lose heat by evaporation?

Answer 12

they coll by water loss from their respiratory tract or sweat glands

Question 13

What is required for an animal to use metabolic heat for thermoregulation?

Answer 13

some form of insulation ie; hair, feathers, scales

Question 14

What kind of fixed properties might influence the amount of heat gained by solar radiation?

Answer 14

reflective or shiny leaves in desert plants, wing pigmentation in alpine butterflies

Question 15

What kind of behavioral and physiological responses might an ectotherm use to regulate body temperature?

Answer 15

Behavioral: parallel or perpendicular basking, shuttling back and fourth between sun and shade
Physiological: changes in peripheral blood flow

Question 16

Give three reasons why an ectotherm might not regulate its body temperature

Answer 16

1) regulatory power may be limited
2) they are dependent on external heat sources
3) there may be costs associated with temperature regulation

Question 17

What does Q10 represent?

Answer 17

An increase in metabolic rate for a 10 degree Celsius rise in body temperature in an ectotherm

Question 18

Distinguish between acclimatization and acclimation.

Answer 18

Acclimatization are adjustments in behavior to regulate body temperature that occur in nature. When the adjustments are induced under laboratory conditions it is acclimation

Question 19

Distinguish between hibernation and estivation and give examples of each.

Answer 19

Hibernation is a way of coping with extremely low temperatures by allowing body temperature to fall to those of its surroundings ie; bats, frogs, rodents. To estuvate is avoiding extremely high temperature or dry conditions ie; desert frogs.

Question 20

Distinguish between freeze-resistance and freeze-tolerance.

Answer 20

Freeze-resistant: will not freeze, can survive it no problem

Freeze-tolerant: can tolerate it to a certain extent

Question 21

Give two possible lethal consequences of high temperatures for living organisms

Answer 21

1) inactivation of enzymes

2) dehydration

Question 22

What are thermophilic procaryotes and where to they live?

Answer 22

Heat tolerant organisms that live in hot springs where temperatures get close to the boiling point

Question 23

In what habitat characterized by high temperatures and pressures might you find chemosynthetic bacteria?

Answer 23

hydrothermal vents

Question 24

Provide a complete definition of the thermoneutral zone of an endotherm.

Answer 24

A range of temperatures over which an endothermic homeotherm can maintain a basal metabolic rate and which heat gain/loss can be adjusted by metabolically inexpensive means.

Question 25

What happens to an endotherm above and below the thermoneutral zone?

Answer 25

metabolic rate increases

Question 26

What are some metabolically inexpensive ways in which an endotherm might adjust heat gain or loss from its body?

Answer 26

fluffing feathers or raising hair

Question 27

Explain why ectotherms have high production efficiencies, are able to occupy habitats with seasonal food supplies or little oxygen and are able to assume shapes and sizes with high surface area to volume ratios.

Answer 27

They have low metabolic rates so these things are not metabollically expensive because they don’t rely on just their bodies for temperature regulation

Question 28

Explain how ectothermy favors anerobic metabolism.

Answer 28

because they are not solely depending on their own metabolism, they rely on their surroundings too, so they don’t have to constantly waste energy on aerobic metabolism

Question 29

What are the disadvantages of ectothermy?

Answer 29

they cannot occupy habitats with insufficient heat, can’t operate efficiently in darkness or shade and cannot maintain high levels of sustained activity for long.

Question 30

What are the advantages and disadvantages with endothermy?

Answer 30

Advantages: can live in high altitudes/latitudes, can be active in the shade or at night an can maintain high-level activity
Disadvantages: high energy costs, little left for reproduction and the young must be fed until they can eat adult food

Question 31

What is ecotypic variation and how is it important to the ecology of individuals?

Answer 31

It is the ability to withstand certain temperatures due to genetic differences. This allows certain organisms to live in certain places.

Question 32

What is Bergmann’s Rule?

Answer 32

In animals having broad ranges, individuals from colder climates are often larger than members of the same species from warmer parts of their range

Question 33

What is Allen’s Rule?

Answer 33

Endothermic animals from cold climates usually have shorter extremities than animals with otherwise similar characteristics from warmer climates.

Question 34

What is Gloger’s Rule?

Answer 34

Generalization that among endotherms, those living in warm and humid areas are more heavily pigmented (darker) than those living in cool, dry areas

Question 35

Life-zones would be applied to what type of habitat?

Answer 35

mountains

Question 36

What is the normal dry adiabatic lapse rate?

Answer 36

1 degree Celsius per 100 meters

Question 37

What is an average moist adiabatic lapse rate?

Answer 37

0.6 degree Celsius per 100 meters

Question 38

Explain why the moist adiabatic lapse rate is lower than the dry adiabatic lapse rate.

Answer 38

If the air contains moisture, some of it will condense as it cools, releasing heat.

Question 39

What is meant by an environmental lapse rate?

Answer 39

As you move up a mountain side, the air will be cooled.

Question 40

How does temperature influence the concentration of dissolved oxygen in aquatic habitats?

Answer 40

As the temperature of water increases, the solubility of oxygen decreases

Question 41

What is thermal pollution and what are some of its possible consequences?

Answer 41

Thermal pollution is raising of the temperature in aquatic ecosystems.
Possible consequences: low dissolved oxygen, low food supply, high susceptibility to disease

Question 42

What is acid precipitation and what are some of its possible consequences?

Answer 42

It is low pH rain
Possible consequences: influences distribution and abundance of organisms, availability of nutrients, concentrations of toxins

Question 43

In what type of habitat are extreme saline conditions most likely?

Answer 43

Desert regions

Question 44

Provides two possible benefits of lightning-caused fires in nature?

Answer 44

1) plant reproduction

2) Keep back the spread of trees in prairie regions