Unit 2 Test Insurance: 2.4 - 2.7

Question 1

Identify three or four conditions for which organisms have a range of tolerance.

Answer 1

temperature, salinity, pH, and sunlight

Question 2

Describe the relationship between genetic diversity and ecological range of tolerance.

Answer 2

The more genetic diversity the greater the ecological range of tolerance will be since some individuals will have an extended range that is more fit for their ecosystem, which they will pass down. Less genetic diversity lessens the chance of this since there aren’t as many opportunities.

Question 3

Describe ecological tolerance

Answer 3

Ecological tolerance are conditions that an organism can endure before injury or death results.

Question 4

Identify the three zones of ecological tolerance.

Answer 4

The three zones of ecological tolerance are optimal range, physiological stress, and zone of intolerance.

Question 5

Optimal Zone

Answer 5

organisms survive, grow, and reproduce

Question 6

Zone of Physiological Stress

Answer 6

organisms survive, but experience stress: infertility, lack of growth, less activity

Question 7

Zone of Intolerance

Answer 7

where organisms will die

Question 8

Provide an example of a physiological stressor or impact an organism could experience in conditions outside of its range of tolerance.

Answer 8

A physiological stressor that can impact an organism is temperature.

At temperatures too high or too low for their tolerance, their activity and health could decrease, but not enough to kill them

Question 9

Identify THREE examples of natural ecosystem disruptions

Answer 9

Three natural ecosystem disturbances are droughts, hurricanes, and forest fires.

Question 10

Periodic Events

Answer 10

occur with regular frequency

such as (dry-wet seasons)

Question 11

Episodic Events

Answer 11

Occasional events with irregular frequency

(such as hurricanes, droughts, and fires)

Question 12

Random Events

Answer 12

no regular frequency

(such as volcanos, earthquakes, asteroids)

Question 13

Identify 2-3 reasons that earth’s climate has changed over geological time

Answer 13

• changes in earth’s orbit & tilt
• volcanic emissions

Question 14

Describe why sea level has varied on earth over time

Answer 14

Rising CO2 levels have cause glacial ice to melt

Question 15

Describe migration

Answer 15

moving to a new habitat as the result of natural disruptions

Question 16

Identify 3 reasons that a population would migrate

Answer 16

• rising climates
• lack of food sources
• changing seasons
• environment is changing too fast*

Question 17

Define adaptation

Answer 17

a new trait that increases in organism’s fitness (ability to survive & reproduce)

Question 18

Describe how adaptations arise in a population

Answer 18

Adaptations arise when mutations in an individual occur and get passed down to offspring until more/all population has the same trait

Question 19

Define natural selection

Answer 19

organisms that are better adapted to their environment survive and reproduce

Question 20

Describe what a selective force is and provide an example

Answer 20

A selective force/pressure is the environmental condition that kills individuals WITHOUT ADAPTATION

e.g predation like hawk

Question 21

Explain how environmental change can lead to evolution or extinction of a species

Answer 21

Environmental change leads to certain traits becoming adaptations for being advantageous which can lead to species evolving. However, if environmental change is too fast and organisms can’t keep up by adapting, they will die out or emigrate.

Question 22

Primary Succession

Answer 22

starts from BARE ROCK in an area with no previous soil formation

Question 23

Secondary Succession

Answer 23

starts from already established soil, where DISTURBANCE cleared out plant life

Question 24

Describe what a pioneer species is

Answer 24

species that appears first when the ground is bare rock or bare soil

such as moss

Question 25

Late Successional / Climax Community

Answer 25

appears last after soil is deep and with nutrients (after cycles of death and growth)

large trees, maple & oak