A closer look at variation Section 4.0 A closer look at variation

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

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.

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

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

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

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

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

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.

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

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

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)

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

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!

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)

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.

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

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

What humans do in a nutshell Protected Areas / National Parks

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

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

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