Section 4.0 Human Activity Affects Biological Diversity

Goals for this Section: 1. Identify the effects of extinction and extirpation on the amount of biological diversity seen in and ecosystem. 2. Distinguish between artificial and natural selection. 3. Describe the use of biotechnology in various fields. 4. Describe new technologies that are used to recombine genetic material. 5. Evaluate the success and limitations of strategies used to reduce the loss of species diversity.

4.1 – The Reduction of Biological Diversity Species and ecosystems are being stressed by humans’ demands for natural resources The result is a decline in the genetic, species, and ecosystem diversity on Earth The extinction of species, and the reduction in the population of other species reduces biological diversity

Extinction and Extirpation Extinction: Extirpation:

The Status of Organisms in Alberta Extirpated: Endangered:

The Status of Organisms in Alberta Threatened Special Concern

Natural Causes of Extinction & Extirpation Catastrophic Events Lack of food due to overpopulation

Natural Causes of Extinction & Extirpation Disease Overspecialization

Human Causes of Extinctions & Extirpations Habitat Destruction Introduction of Non-Native Species

Human Causes of Extinctions & Extirpations Over-Hunting

Effects of Extinctions & Extirpations Both extinctions & extirpations reduce biological diversity The main difference is that extinctions reduce biological diversity worldwide, while extirpations reduce biological diversity in a particular area Often extirpations in one area affect other species in the same area as well

4.2 – Selecting Desirable Traits Humans have used artificial selection for thousands of years This produces breeds of plants and animals that have particular desired traits

Biotechnology Now that we understand how genes within cells work, we can use more “high tech” methods of selecting traits We can now create clones of organisms that have the traits that we desire

Cloning We can create clones by taking cells from an organism that we wish to clone The nucleus of the cell is removed and placed in an egg cell that has had its nucleus removed This egg cell is then allowed to develop

Artificial Reproductive Technology In animals, artificial insemination and in vitro fertilization may be used Both of these techniques increase the likelihood of producing offspring with the desired traits

Genetic Engineering Genetic Engineering refers to any technology that directly alters the DNA of an organism We can use genetic engineering to insert DNA from one species into the DNA of another species For example, we can now produce plants that produce toxins that only affect insects (these toxins were originally coded by genes from bacteria)

Examples of Genetic Engineering:

Risks of Genetic Manipulation Risks in Animals:

Risks of Genetic Manipulation Risks in Plants:

Risks of Genetic Manipulation Societal Issues: