Unit A Section 4.1

Question 1

What reduces biological diversity on Earth?

Answer 1

• The extinction of some species,
• the decrease in population of other species,
• and the degradation of ecosystems

Question 2

What is extinction?

Answer 2

Extinction is the disappearance of every individual of a species from the entire planet.

Question 3

How can sudden catastrophic events occur?

Answer 3

• These are events such as earthquakes or volcanic eruptions that cause sudden changes in the environment
• The The last major environmental change was about 1.8 million years ago during the Pleistocene epoch, which is commonly known as the Ice Age.

Question 4

What is Extirpation?

Answer 4

Extirpation is a local extinction or the disappearance of a species from a particular area.

Question 5

How can extirpation happen?

Answer 5

road building or deforestation

Question 6

How is natural selection not always the solution for survival?

Answer 6

Natural selection is usually a slow process. Even if there is a lot of
variation within a species, sometimes the environment changes too much
and too quickly for the species to survive.

Question 7

extinctions and extirpations were due to natural causes, such as:

Answer 7

• catastrophic events such as volcanic eruptions, floods, or fires
• lack of food due to overpopulation
• disease

Question 8

What is overspecialization?

Answer 8

-Overspecialization is another natural cause of extinction
-Sometimes organisms have adaptations that suit them to only a narrow set of environmental conditions.
-This probably happens because the
environment that the organism inhabits remains unchanged for a very long time.

Question 9

What are the ways Humans cause rapid changes to habitat?

Answer 9

• Construction of buildings,
• agricultural development,
• logging, and the damming of rivers

all change environments

Question 10

How much prairie in Alberta is still in natural condition

Answer 10

only 20% of the area once covered by native

prairie species is still in its natural condition.

Question 11

What is a type of habitat destruction?

Answer 11

-Pollution is a particular kind of habitat destruction

Question 12

How does pollution affect the environment?

Answer 12

-Pollution often affects not only the immediate area where humans are but also areas farther away.

• Some chemicals can cause an increase in the number of birth defects in species.
• This often occurs first in aquatic species such as fish, frogs, and toads.

Question 13

Why are the effects of habitat destruction in tropical areas can be severe?

Answer 13

Because tropical rain forests have the highest diversity of species of any area on the planet, the loss of these habitats can cause the extinction or extirpation of a very large number of species.

Question 14

What is the problem with the Introduction of Non-Native Species?

Answer 14

• When introduced species use the same resources as native species,
• they compete with the native species and cause the number of native species to decline, simply because there is less of everything.

-EX. Cattle now graze where bison once roamed and attempts to reintroduce the bison are limited due to the competition for grazing resources.

Question 15

What was the major cause of the decline and eventual extirpation of the plains bison over most of its range, and of the extinction of the passenger pigeon?

Answer 15

Over-hunting

• Mainly for leisure and sport.
• Sometimes species were hunted to deliberately extirpate them.(prairie dogs)

Question 16

What are the results of extinction?

Answer 16

• reduces biological diversity.

- Extinctions reduce the number of species on the planet.

Question 17

What are the results of extirpation?

Answer 17

• Reduces biological diversity

- Extirpations reduce biological diversity in areas from which the organism has disappeared