Homework
Read Section 1.10, pages 32­33
Complete Questions #1­4, page 33
Title: May 14­8:25 AM (1 of 20)
1)
Why is sunlight important for the biosphere?
Title: May 18­8:03 AM (2 of 20)
2)
Make a pie graph showing what happens to the energy from
sunlight that penetrates into Earth's atmosphere. Label each
piece of the graph.
0.023%
44%
1%
25%
30%
Title: May 18­8:04 AM (3 of 20)
Title: May 18­9:30 AM (4 of 20)
2)
The point of this is to take a close look at the numbers...
(First of all...what problem do you notice about the percentages?
Why do you think this is?)
More importantly, look at how much of the sunlight that reaches
Earth's surface actually gets captured and used by living things.
Title: May 18­8:10 AM (5 of 20)
3)
In your own words, describe the albedo effect.
Title: May 18­8:12 AM (6 of 20)
Title: May 18­9:42 AM (7 of 20)
Title: May 18­9:52 AM (8 of 20)
4)
Eruption data from volcanoes.
Volcano
Year of
eruption
Period of low
temperatures
Mt. Asama (Japan)
1783
1784­91
Mt. Tamboro (Indonesia)
1815
1816­20
Mt. Krakatoa (Indonesia)
1883
1884­90
Mt. St. Helens (US)
1980
1981­82
a) explain why temps fall
b) how could you test this?
c) predict which eruption was largest
d) how would world temps change if volcanic activity stopped?
Title: May 18­8:13 AM (9 of 20)
Title: May 18­9:58 AM (10 of 20)
Effects of Extinction
Because all organisms in an ecosystem are connected, the decreased biodiversity caused by the loss of a single species can have effects on a wide variety of populations, with often unpredictable results.
Two examples of this are sea otters and black­ footed ferrets.
Title: May 14­8:25 AM (11 of 20)
Sea Otters
Sea otters were hunted for their fur along the west coast of North America, and in Asia.
They were nearly
hunted into extinction; but, not only the sea otters were affected.
Title: May 14­8:25 AM (12 of 20)
Sea otters eat sea urchins. When the otter population dropped, the numbers of urchins skyrocketed.
Urchins eat kelp, a type of seaweed that forms the basis of many food chains involving commercially important fish...
The domino effect:
loss of otters resulted in lower fish populations when their food source dropped.
Title: May 14­8:25 AM (13 of 20)
Black­footed Ferrets
In the 1800s, prairie dogs were considered a pest because they ate grass that cattle used for grazing, and because their burrows could cause injuries to cattle or horses if they stepped in them.
Prairie dogs were
killed by the thousands. But that wasn’t all that happened...
Title: May 14­8:25 AM (14 of 20)
Black footed ferrets are predators, but they are “specialist” feeders...their diet consists almost entirely of a single food source...
prairie dogs.
Title: May 14­8:33 AM (15 of 20)
When the prairie dog population dropped, the ferrets very nearly became extinct as well, and are still one of the world’s most endangered species.*
*In 1985, there were only 18 known; by 2005, captive breeding programs had increased this number to 500.
Title: May 14­8:25 AM (16 of 20)
Risk Factors
The black­footed ferret shows one of the factors that may make a species more prone to extinction than others.
The ferrets were specialists...they were very well adapted to their environment, and very effective at hunting their main prey. However, the ferrets were unable to change and adapt when part of their environment (their food source) was altered.
Title: May 14­8:25 AM (17 of 20)
Factors which can put a species at risk of
extinction can include: (what do you think?)
Title: May 14­8:25 AM (18 of 20)
How did you do?
• Poor reproductive success
• Competition from a newly introduced species (can you think of an example on PEI?)
• Disease
• Destruction of another species
• Change in climate
• Hunting by humans
And probably the greatest risk factor in the modern world...
Loss of habitat
Title: May 14­8:40 AM (19 of 20)
Homework
Read Section 1.10 (pages 34­39)
Complete Questions #4, 7­10
Title: May 17­6:27 PM (20 of 20)