Chapter 16 Human Impact on Ecosystems

Changing the Landscape Everywhere humans have traveled, they have changed the landscape to suit their needs – Introducing invasive species – Overusing resources How are some of the ways in which we have changed Earth’s layers (biosphere, geosphere, atmosphere, hydrosphere)?

Scientists are Worried… …that the gigantic impact we have on this planet may harm Earth’s biodiversity. So we measure it: – Species Richness – Population Evenness MiniLab (in table groups, max 4): – Count the number of colors of gummy bears you have (richness) – Count the number of each color you have (evenness)

The Value of Biodiversity Biodiversity is on of Earth’s greatest natural resources Ecosystem diversity refers to the variety of habitats and communities in the biosphere Species diversity refers to the number of different species in the biosphere Genetic diversity refers to the sum total of all genetic info on Earth

Threats to Biodiversity Human activity can reduce biodiversity by altering habitats and eliminating species through extinction Habitat Fragmentation is something that takes place when human activities split up habitats, isolating populations Non-sustainable hunting practices can lead to extinction of some species Invasive species introduction can lead to extinction of plants and animals

Pollution and Biomagnification While all forms of pollution pose a threat to the planet, introduction of toxic chemicals into the environment is the most dangerous Examples include arsenic, lead and mercury, along with 272 others listed by the CDC An historical example includes DDT and how it harmed birds at the top of the food chain without direct application to the animal

Ozone Thinning and Acid Rain Ozone thinning leads to more UV rays reaching Earth’s surface. CFCs are a big contributor to ozone thinning. Acid Rain is caused by industrial pollution and raises the pH of rain water. This will damage plant life and change biodiversity in large swaths of the planet.

Renewable and Nonrenewable Resources Renewable Resource – can regenerate quickly and are replaceable Examples: Nonrenewable Resource – Either will not regenerate or will take eons to regenerate Examples:

Sustainable Use Sustainable Use is a way of using natural resources that does not deplete them These industries work to sustainably use resources daily: – Fisheries – Agriculture – Land Developers

Top 5 Resources Renewable or Nonrenewable? – Land – Forest – Ocean – Air – Freshwater

Conservation of Biodiversity By protecting habitats for wildlife, we are conserving biodiversity Other techniques include zoo-based breeding programs that rescue animals or breed them in captivity and then return them to the wild Conservation takes place on land as well as in marine environments Conservation challenges include political pressures, financial pressures and balance between human and wild needs

Conservation Biology Conservation biologists work to try to protect biodiversity in areas that are threatened. Restoration biologists work to restore damaged ecosystems. Ecotourism is a form of tourism that supports conservation and brings economic benefit to local people.