Humans in the Biosphere Ms. Schultz

The root cause of many environmental issues is the size of the human population Currently, there are over 7 billion people on this planet

When did human population growth explode? The 1950’s on Why? Better access to food Better sanitation Better medical care (vaccines)

The Human Population Animations Global Human Population Animation World Population Counter

Age Distribution Diagrams show populations broken down by age group and gender. One of these countries will experience negative growth, one high growth, and one slow growth. Which is which? Negative Growth Slow Growth High Growth

Africa United States Most future population growth will be in developing countries.

Spain compared to Tanzania SpainTanzania 2012 Pop46 million48 million 2050 Pop48 million138 million Source:

Humans Affect the Biosphere in 3 Ways: A.Global Climate Change B.The Ozone Layer C. Threatening Biodiversity i. Habitat Destruction ii. Invasive Species iii. Pollution Biological Magnification/Bioaccumulation Acid Rain Hog Waste Lagoons

A. Global Climate Change CH 4 H2OH2O CO 2 UV Light IR Light

UV light gets through but IR light reflected back is trapped by greenhouse gases (like CO 2, CH 4, and H 2 0) keeping the heat around the planet.

Sources that add greenhouse gases Burning fossil fuels and wood

Possible Effects of Global Warming Floods Drought Spread of Disease through Insects

B. The Ozone Layer UV light causes cancer, eye damage, and can damage plant tissue. The ozone layer protects us from UV light.

The hole in ozone layer – South Pole

What Destroys the Ozone Layer? CFC’s have been linked to the hole in the ozone layer. Chlorofluorocarbons (CFC’s) are broken apart by UV light. This causes a chain of chemical reactions that results in ozone being broken apart. CFC’s were used in aerosol cans, and as coolants in freezers and air conditioners. They are now banned.

C. Threatening Biodiversity Habitat Destruction Invasive Species Biological Magnificiation/Bioaccumulation Acid Rain Hog Waste Lagoons

Habitat Destruction We destroy habitats to build houses and to get resources like wood. Organisms cannot survive because they don’t have what they need. Clear cutting can also lead to polluted water run-off.

Invasive Species These are species that don’t belong in an area. They get here from other countries in a number of ways (on purpose or by accident). They outcompete local organisms and take over. Kudzu, Fire Ants, Snakehead Fish, Anaconda

Biological Magnification Biological magnification/Bioaccumulation is when pesticides build up in animal tissue as you move up a food chain. Top level consumers wind up poisoned or with other problems (birds lay weak eggs).

Biological Magnification/ Bioaccumulation

DDT in Borneo DDT was used in Borneo to kill mosquitoes. Lizards ate the mosquitoes. Cats ate the lizards. Cats began dying. With no cats, the rat population grew. Rats began spreading disease. They came up with an interesting solution.

Parachuting Cats

DDT in the United States DDT was used to kill mosquitoes. DDT bioaccumulated and was found in high levels in the bald eagle. DDT caused the birds to lay eggs with pores in their shells. When the parent birds sat on the eggs, the eggs broke. Our national bird almost went extinct.

DDT is still in the environment despite the fact the last time it was sprayed was over 20 years ago.

Acid Rain Acid rain is precipitation with a low pH. When air pollutants combine with water in the atmosphere, a chemical reaction occurs that results in the production of sulfuric acid. Later, when clouds form over the high peaks, the precipitation falls as acid rain. Air pollution from power plants and industries in Tennessee and the Ohio River valley that burn high sulfur coal is picked up by the prevailing winds and carried toward the mountains of North Carolina and Virginia. Many trees in North Carolina forests are dying due to acid rain. North Carolina Mountains

Hog Waste Lagoons Hog Waste lagoons add extra nitrogen into waterways. Extra nitrogen can lead to algae growing to toxic levels. In 1995 an eight-acre hog- waste lagoon in North Carolina burst, spilling 25 million gallons of manure into the New River. The spill killed about 10 million fish and closed 364,000 acres of coastal wetlands to shellfishing.

Why is biodiversity important?

Many medicines come from nature We get digitalis, a heart medication, from foxglove.

We get genetic diversity Most crop plants have wild relatives with useful traits. We will visit this “library” when we need genes to improve our crop plants.

Ecosystems with more species are more stable Ecosystems with more organisms are more stable (or homeostatic).

What can you do to help? Are your actions sustainable (able to continue for the future)?

Stewardship Stewardship means responsible planning and management of resources. Examples of good stewardship include: Planting trees when trees are cut. Having laws to prevent overfishing. Conserving resources.

References /000f1/000f1c7d.jpg DDTInFoodChain-L.jpg

References tany/images/Digitalis/Digitalisflowers.jpg commons/b/bc/Rainforest_Fatu_Hiva.jpg JPG