How Humans Disrupt the Ecosystem. Disrupting Physical Habitats I.Disrupting Physical Habitats A.Humans alter and replace natural habitats with manmade.

How Humans Disrupt the Ecosystem

Disrupting Physical Habitats

I. Disrupting Physical HabitatsA. Humans alter and replace natural habitats

with manmade habitats.

Disrupting Physical Habitats

B. Humans cut down trees, drain and fill swamps and wetlands, divert rivers.

Disrupting Physical Habitats

C. Humans are beginning to alter global habitats.

Disrupting Physical Habitats

D. Burning of fossil fuels leads to global warming.

Hottest temperatures ever recorded

from January to June during

2012.

• The avg. temperatures have climbed 1.4 0F around the world since 1880 (much of it in recent decades).

• The rate of warming is increasing. According to the Panel of Climate Change, 11 of the past 12 years are among the dozen warmest since 1850.

• Areas surrounding the artic, such as Alaska, Western Canada, and eastern Russia have experienced temperatures rising twice the global average.

• Artic ice is rapidly disappearing. Scientist predict the region may have its first ice-free summer by 2040.

• Glacier National Park has lost 123 glaciers since 1910. This averages to the loss of one glacier per year.

• Coral reefs, which are highly sensitive to small changes in water temperature, are undergoing high amounts of bleaching.

• International Plant Protection Convention said in 2007 that it’s “very likely” humans are the cause for recent climate changes.

• The report was based on the work of 2,500 scientist from over 130 countries who concluded that humans have caused all or most of the current planetary warming.

Disrupting Physical Habitats

E. Use of chloroflurocarbons (CFC’s) destroy the ozone (O3).

It’s been estimated a single Cl atom can destroy 100,000 ozone molecules. Since Cl is regenerated at the end of the catalyzed reaction this is how CFCs destroy the ozone.

One of CFCs' most attractive features is their unreactivity - which is instrumental in making them one of the most significant pollutants.

CFCs' lack of reactivity gives them a lifespan which can exceed 100 years in some cases. This gives them time to diffuse into the upper stratosphere. Here, the sun's ultraviolet radiation is strong enough to break off the chlorine atom, which on its own is a highly reactive free radical. This catalyzes the break up of ozone into oxygen by means of a variety of mechanisms.

Disrupting Physical Habitats

• These changes to natural habitats reduce their ability to support living things.

Decrease Species Diversity

II. Decrease Species Diversity – can reduce the number of species in a given area from hundreds or thousands down to only a few. (i.e. Changing a forest to farmland)

Decrease Species Diversity

A. Destroying interactions among species.

Decrease Species Diversity

B. Removing predators (i.e. wolves) often reduces diversity.

Decrease Species Diversity

1. Introduction of exotic species (species that are not native to an area) can disrupt the competitive balances that have coevolved among native (indigenous) species.

Hemlock Woolly Adelgid

Decrease Species Diversity

2. May cause entire ecosystems to collapse.

Three Gorge Dam - China

Examples of Protection

III.Examples of what should be done to protect Earth’s ecosystems.

A. Disrupt the physical habitat as little as possible.

Examples of Protection

B. Avoid decreasing species diversity

Examples of Protection

C. Avoid disrupting species interactions.

Oil Feather Activity

Closure

• Around the world, vast numbers of trees are cut down. The timber from the harvested trees is used for a variety of purposes. In some cases, the cleared land is also used.

• 1. Name five different uses for timber.• 2. Name two different uses for the land cleared of trees.• 3. Name at least three effects of clearing trees on the

organisms that make their homes in the forested areas.• 4. You use may products that come from trees or the land

on which they grew. Is there a way to balance our need for resources with the needs of other organisms for those same resources?