Biodiversity

Question 1

Which three scales does biodiversity exist on?

Answer 1

• Ecosystem/Habitat: variety of ecosystems within a region
• Species: a variety of species within an ecosystem
• Genetic: a variety of genes among individuals of a species

Question 2

How does genetic diversity affect its ability to respond to environmental stressors?

Answer 2

The more genetically diverse a population is, the better it can respond to environmental stressors.

Question 3

Mutation

Answer 3

random change in genetic code produced by a mistake in the copying process, can improve an organism’s chances of survival or reproduction (will be passed on to next generation)

Question 4

Allopatric speciation

Answer 4

process of speciation that occurs with geographic isolation

Question 5

Geographic isolation

Answer 5

Physical separation of a group of individuals from others of the same species

Question 6

Sympatric speciation

Answer 6

evolution of one species into two, without geographic isolation

Question 7

Reproductive isolation

Answer 7

result of two populations within a species evolving separately to the point that they can no longer interbreed & produce viable offspring

Question 8

Fitness

Answer 8

individual’s ability to survive & reproduce

Question 9

Adaptation

Answer 9

trait that improves an individual’s fitness.

Question 10

How does mutation cause evolution?

Answer 10

As the number of mutations accumulates in a population over time, evolution occurs.

Question 11

How does gene flow cause evolution?

Answer 11

process by which individuals move from one population to another & thereby alter the genetic composition of both populations.
The arrival of individuals from adjacent populations alters the frequency of alleles in the population.
- nonadaptive, random process.

Question 12

How does Genetic Drift cause evolution?

Answer 12

change in the genetic composition of a population over time as a result of random mating.
- nonadaptive, random process.

Question 13

Bottleneck effect

Answer 13

reduction in the genetic diversity of a population caused by a reduction in its size

• Reduced population numbers means reduced genetic variation.
• Low genetic variation in a population can cause
• Increased risk of disease & low fertility.
• The bottleneck effect means species are less able to adapt to future environmental changes.
• Resulting low diversity can lead to decline & extinction.

Question 14

Founder effect

Answer 14

A change in the genetic composition of a population as a result of descending from a small number of colonizing individuals.

Question 15

Background extinction rate

Answer 15

Average rate at which species become extinct over the long term.

Question 16

Resilience

Answer 16

The rate at which an ecosystem returns to its original state after a disturbance.

Question 17

Range of tolerance

Answer 17

• limits to abiotic conditions that an individual or species can tolerate

Question 18

Fundamental niche

Answer 18

• suite of abiotic conditions under which a species can survive, grow & reproduce (full range of conditions, includes extremes)

Question 19

Realized niche

Answer 19

• range of abiotic & biotic conditions under which a species actually lives (thrives)

Question 20

Distribution

Answer 20

• areas of the world in which a species lives.

Question 21

What are generalists? When do generalists do well?

Answer 21

Niche generalist - species that can live under a wide range of abiotic or biotic conditions.
- Niche generalists fare better under changing conditions because they have a number of alternative habitats and food sources available; however under stable conditions generalists may be outcompeted by specialists.

Question 22

What are specialists? When do specialists do well?

Answer 22

Niche specialist - species that is specialized to live in a specific habitat or to feed on a small group of species.
- Niche specialists do well when environmental conditions remain relatively constant; however loss of a favored habitat or food source leaves them with few alternatives for survival.

Question 23

How do natural disruptions to an ecosystem affect an ecosystem?

Answer 23

• Make major changes to swathes of habitats

- Force species to adapt, perish or migrate

Question 24

Earth systems processes operate on a range of scale in terms of time. Processes can be:

Answer 24

• periodic (ie. spring rain leading to flooding & deposition of sediment),
• episodic (ie. earthquake causing landslides & soil erosion), or
• random (ie. tornado causing downed trees).