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

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Natural Causes of Extinction & Extirpation

Disease

Overspecialization

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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: