1. A closer look at variation
Section 4.0
A closer look at variation

2. Words you should already know
*Introduced species *Natural Selection
*Selective breeding
*Genetic engineering
*Extinction
*Habitat

3. Reduction of Biological Diversity
The stresses of urbanization and habitat intrusion by farming and industry has resulted in a decline in genetic, species and ecosystem diversity. Extinction, population decreases and degradation of ecosystems reduces biological diversity on the Earth.

4. Extinction and Extirpation
Extinction Extirpation
Javan Rhino now extinct in 2011 from
Vietnam, only a small population of
50 animals left in Indonesia
Thylacine: the Tasmanian Tiger, extinct since 1936 from Australia

5. Natural Causes of Extinction and Extirpation
**Results in a loss of biological diversity**
Natural Selection
Catastrophic Forest Fires
Lack of Food

6. Natural Causes of Extinction and Extirpation
**Results in a loss of biological diversity**
Overspecialization
**Occurs when an organism has a very narrow niche, where the environmental conditions never change**
Giant Panda

7. Human Causes of Extinctions and Extirpations
**Results in a loss of biological diversity**
Habitat Destruction
Logging
Pollution
Construction

8. Introduction of Non-Native Species
Natural Causes of Extinction and Extirpation
**Results in a loss of biological diversity**
Introduction of Non-Native Species
No Natural Predators
Example: Purple loostrife

9. Natural Causes of Extinction and Extirpation
**Results in a loss of biological diversity**
Over-Hunting
species are hunted to deliberately extirpate them. The black-tailed prairie dogs were considered a pest in the 1930's and were hunted to reduce their numbers.

10. Selecting Desirable Traits
Artificial Selection is the process of selecting and breeding individuals with desirable traits to produce offspring with the desired traits.

11. Cloning
Example: Dolly the sheep (first mammal clone!)

13. Artificial insemination
Occurs when gametes are brought together artificially (NOT naturally).
Artificial insemination (AI) is a process by which sperm are collected from the male, processed, stored and artificially introduced into the female reproductive tract for the purpose of conception. AI has become one of the most important techniques ever devised for the genetic improvement of farm animals. It has been most widely used for breeding dairy cattle and has made bulls of high genetic merit available to all. (from engormix.com)

14. In vitro fertilization
Occurs when gametes are joined together in a petri-dish (vitro means outside of the body)

15. Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genetic material in a way that does not occur under natural conditions.
Example: Tomatoes!

16. Tomato examples of genetic engineering
Delayed ripening: An early tomato was developed that contained an antifreeze gene (afa3) from the winter flounder with the aim of increasing the tomato's tolerance to frost (see Fish tomato). The antifreeze protein was found to inhibit ice recrystallization in the flounders blood, but had no effect when expressed in transgenic tobacco.[15] The resulting tomato was never commercialized, but raised ethical questions over adding genes from one kingdom to another.[16]
Environmental stress tolerance: An early tomato was developed that contained an antifreeze gene (afa3) from the winter flounder with the aim of increasing the tomato's tolerance to frost (see Fish tomato). The antifreeze protein was found to inhibit ice recrystallization in the flounders blood, but had no effect when expressed in transgenic tobacco.[15] The resulting tomato was never commercialized, but raised ethical questions over adding genes from one kingdom to another.[16]
Pest resistance: The insecticidal toxin from the bacterium Bacillus thuringiensis has been inserted into a tomato plant.[21] When field tested they showed resistance to the tobacco hornworm (Manduca sexta), tomato fruitworm (Heliothis zea), the tomato pinworm (Keiferia lycopersicella) and the tomato fruit borer (Helicoverpa armigera)

17. Tomato examples of genetic engineering
Improved nutrition: Tomatoes have been altered in attempts to improve their flavour or nutritional content. In 2000, the concentration of pro-vitamin A was increased by adding a bacterial gene.
Improved taste: When geraniol synthase from lemon basil (Ocimum basilicum) was expressed in tomato fruits under a fruit-specific promoter, 60% of untrained taste testers preferred the taste and smell of the transgenic tomatoes. The fruits contained around half the amount of lycopene, reducing the health benefits of eating them
Vaccines: Tomatos (along with potatoes, bananas and other plants) are being investigated as vehicles for delivering edible vaccines.

18. Reducing Our Impact on Biological Diversity
Preserving global biological diversity is a challenge that is receiving much attention. The 1995 Canadian Biodiversity Strategy was created to preserve biodiversity in Canada. It will be done through the cooperation of many levels of government, along with many groups, agencies and individuals, who are dedicated to preserving our biodiverse future.
Protected areas
Restoration programs for ecosystems and species
Resource use policies
Controlling the introduction and spread of exotic species
Conservation of genetic resources

19. What humans do in a nutshell
Zoos = Captive breeding / education

20. What humans do in a nutshell
Protected Areas / National Parks

21. What humans do in a nutshell
Seed Banks
Chicago
Millennium Seed Bank in London

22. What humans do in a nutshell
Resource Use Policies (laws put in place by governments)

23. Biotechnology Beneficial or Detrimental? Short Class Presentation
(1) Should grocery stores in Canada have to tell people when foods have been genetically modified? (2) Are zoos really beneficial in protecting animal diversity? (3) Why is cloning so controversial? (4) Is it morally right to allow selective breeding? Doesn`t it go against natural selection? (5) What role do you think humans play in protecting biological diversity on the planet? Why do you think that?
In your lab grous, pick a question to research and be able to present your findings to the class