Warm up 9 12 11
Sponsored Links
This presentation is the property of its rightful owner.
1 / 43

Warm-Up 9/12/11 PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

Warm-Up 9/12/11. Factors influencing Populations. Objective- For students to understand that every action has a consequence. Essential Question How does the increase in population effect the overall impact on the Earth?. Human Population Growth recap.

Download Presentation

Warm-Up 9/12/11

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Warm-Up 9/12/11

Factors influencing Populations

Objective- For students to understand that every action has a consequence.Essential QuestionHow does the increase in population effect the overall impact on the Earth?

Human Population Growth recap

  • Human population has increased at an almost exponential rate.

  • With this growth comes an increase in demand for land, food, water, energy and other resources.

  • As human numbers grow species and their habitat diminish.


  • Biodiversity is the variety of all forms of life throughout an ecosystem.

  • High rates of extinction are quickly reducing biodiversity especially in areas of the world with high human population density and growth.

  • The direct and indirect effects that humans have had on biodiversity is challenging as can be seen from the following flow chart.

Human Population

Size Resources use

Human Enterprises

Agriculture Industry Recreation International Commerce



Biotic Additions

and Loss

Land Transformation

Land Clearing










Climate Change

Loss of

Biological Diversity

Extinction of species

And populations

Loss of ecosystems




Land cover

Vitousek et. al (1997) Science, 277, p.494-499

What is a resource?

  • a source of supply, support, or aid, especially one that can be readily drawn upon when needed.

    • Webster’s Dictionary

      What does this mean to us?

Allegorical Apple Demo

  • What conclusions can we draw about the relationship between a growing population and a shrinking amount of land capable of growing food for those people?

Humans Change of the EarthExpressed as % Change

Vitousek et. al (1997) Science, 277, p.494-499

Biodiversity and People

  • Places on earth with some of the greatest biodiversity such as: South America, Equatorial Africa, India, Indonesia and Coastal regions also show the greatest density and fastest rate of growth of people.


World Population


  • Extinction is the natural order. In fact, of all the species which have ever existed, 99.9 % are now extinct!

  • The current extinction rates, however, may be as much as 40 - 100 times the normal “background” or natural rate for extinction.


  • Paul Ralph Ehrlich at Stanford University predicts that soon, this rate may be as much as 400 times the "normal", average, rate of extinction!

  • Much of this increase in extinction rate appears to be due to the impact of humans.

    • Habitat Depletion

    • Pollution

    • Introduction of disease

    • Introduction of invasive species

    • Over exploitation


  • 25% of the earth’s birds species have been driven to extinction by humans (especially on islands).

  • Threatened with Extinction

    • 11% of birds

    • 18% of mammals

    • 5% of fish

    • 8% of plants

Great Auk

Loss of birds


Extinction Rate

Globally, the number of people living within 100 km of the coast increased from roughly 2 billion in 1990 to 2.2 billion in 1995 (39 percent of the world's population).

The Oceans and the Coast

Coastal Area Population Density

  • 3.2 Billion (1/2 of the planet) live and work within 125 miles from a coastline.

  • 4 Billion (2/3) live within 250 miles from the coast.

Coastline, Estuaries and Reefs

  • While 75% of the earth is covered by oceans, the greatest levels of marine biodiversity are found near the coast.

  • This Neritic zone of the ocean has depth of less than 250 meters and so the abundant photosynthetic organisms create a habitat for great biodiversity.

Kelp Forest Near Monterey California

Approximately 50% of mangrove ecosystems globally have been transformed or destroyed by human activity

Great Barrier Reef, Australia

Human causes of Coral Reefs Depletions

  • Pollution runoff: nitrates from fertilizers, point-source pollution, oil spills.

  • Exploitation: Over 90% of saltwater aquarium fish are taken directly from reefs.

  • Increased water temperatures: global warming, increased El Nino.

  • Direct Destruction: Boats, fishing nets, removal of coral for sale.

Global Fish Supply







Million Metric Tons














(Grainger 1998)

Over fishing

  • Aquaculture is a vital aspect of the food-production industry

  • Global human population is expected to rise to over 9 billion by 2050

  • Placing tremendous pressure on food-production systems

Tropical Rainforests Facts

  • Contains more than half of the 5 to 80 million species of plants and animals worldwide.

  • Approximately 1/3 of the world’s bird species are found in South American Rainforests.

Tropical Rainforests Facts

  • Each year approximately 78 million acres of rainforest are destroyed.

  • As many as 137 species are going extinct each day.

  • The substrate (soil) is poor with most of the nutrients existing in the trees and plants.

Tropical Rainforest Facts

  • Poor soil leads to burning the land to increase top-soil nutrients.

  • Burning trees releases carbon into the atmosphere which exacerbates the greenhouse effect and increases temperature.

Tropical Rainforest and Population Growth

  • Today, more than 3 billion people live in the tropics alone; more than lived in the entire world in 1950.

  • Millions of people are destroying the rainforest simply to survive.

  • These people, usually small farmers, have nowhere to grow crops to feed their families, so they wander into the rainforest.

Rainforest and Primates

  • Out of some 240 known primate species, 19 are critically endangered, up from 13 in 1996.

  • Their remaining numbers range from less than a few hundred to, at most, a few thousand individuals.

  • Includes 8 monkeys from Brazil's Atlantic rainforest, where 97 percent of the forest has been lost, 2 apes and a monkey from Indonesia, 3 monkeys from Viet Nam, 1 each from Kenya and Peru, and 3 lemur species from Madagascar.


Human activity = Impacts

  • Human activity is a major cause of environmental change

  • Environment degradation has an impact not only on human beings but on all species and most natural systems

Human dependence on the natural Environment

  • a resource for food supply

  • a major source of medicines

  • an energy source

  • a source for recreation

  • natural resources for industrial products

















Human wants are never ending


  • Humans require a great deal of resources and space and have not had a record of sharing.

  • The earth is losing biodiversity at a rate not seen since the mass extinction that killed the dinosaurs 65 million years ago.

  • Our increasing numbers will certainly increase the rate at which animals and plants are lost.


  • "For if one link in nature's chain might be lost, another might be lost, until the whole of things will vanish by piecemeal."- Thomas Jefferson

Exit Ticket

  • Describe three things in your life that are NEEDS.

  • Describe three things in your life that are WANTS

  • Login