1. Topic 4

2. Learning objectives: By the end of the lesson you should be able to: Explain the impact of the environment on the phenotype of an organism. Describe how identical twins or clones can be used to assess the impact of the environment on a organisms phenotype. State whether environmental impact on phenotype can be passed on to the next generation.

3. 1: Environmental effects on the Environment For most polygenic characteristics the phenotype is determined by _______________ ____________ which determines the ___________ development of the individual _______________ which influences the _________ development of the individual two factors genotypepotential environment actual

4. The combined effect of genotype and phenotype is often shown as e.g. over the last century the average height of humans has increased as their diet has improved e.g. For chlorophyll formation in tomatoes, a mutant tomato plant which is white will turn green if grown in temperatures above 26 oC GenotypeEnvironmentPhenotype

5. 2: Environmental effects and inheritance Changes in phenotype are not inherited and so do not affect evolution. The ______________________ on the phenotype can be dramatic e.g. a land mine may deprive a person of a leg. _____________________________, so only changes to a person’s genotype can affect ___________________, and therefore _______________ e.g. The land mine victim with one leg can have healthy children with 2 legs effect of the environment Only the genotype is inherited future generations evolution

6. 3: Studying the effects of the environment on the phenotype Clones are genetically identical individuals The effects of the ____________ on the _______________ _______________ is studied using _________ environmentdevelopment of characteristicsclones Cloned plants grown in ___________________ show effects of that condition on the development. Since the genotypes are the same, __________________________ e.g. Plants grown in light are green and healthy but clones grown in the dark are yellow and sickly different conditions Any difference in the plant must be due to the environment

7. Identical twins are _________ and are useful in studying the effects of “nature” (genotype) and “nurture” (environment on development Differences between identical twins must be due to the _____________________________ clones effects of the environment

8. Learning objectives: By the end of the lesson you should be able to: Define the term Natural Selection. Describe the mechanisms which drive natural selection Explain how natural selection has acted on the peppered moth

9. 4: Evolution and natural selection Evolution is the scientific explanation for the ____________________________________ over the 3.5 billion years since life first appeared on Earth. The current theory of evolution was first proposed by ______________ in the 1850’s It is based on simple observations Changes seen in species and biodiversity Charles Darwin

10. Organisms _____________________ than the environment can support This results in _____________ for limited resources There is a __________________ the effects of Lack of water / food Lack of shelter predation disease produce more offspring competition struggle to survive

11. Members of species show ___________________ due to the expression of different alleles Those individuals with ________________________ to the environment are more likely to _____________ ____________________ Those individuals with ______________________ to the environment are more likely to ____________ ________________________ inherited variation phenotypes better suited survive and breed and so pass on their genes phenotypes less suited Die so do not pass on their genes

12. This process is called __________________ and results in ________________________ Over ______________________ the characteristics of ____________________ e.g. the peppered moth story natural selection survival of the fittest many generations species may change

13. 5: The environment and evolution If the environment __________________ there is no pressure for a successful species to evolve E.g. coelacanth is a deep sea fish which looks exactly the same today as 80 million years ago does not change

14. If the environment ________________________ then species may become ____________ E.g. 65 million years ago many species including the dinosaurs disappeared due perhaps to the impact of a large asteroid Changes too rapidly extinct

15. ________________ are causing __________________ and so many species which cannot adapt quickly enough will become extinct. Borneo Human activities rapid environmental change

16. Learning objectives: By the end of the lesson you should be able to: Explain the process of selective breeding. Describe the advantages and disadvantages of selective breeding.

17. 6: Selective breeding For thousands of years __________ have been _______________________________________________ to produce the next generation. This is in the hope of _____________ certain characteristics humans selecting individuals with favourable characteristics improving This process is called artificial selection or _______________ ________________________ selective breeding In this way most of the animals and plants used by humans have been ___________________________________ modified from their ancestors

18. Some examples of characteristics which have been ____________ are Size and taste of __________________ Beef and milk yield in _________________ Disease resistance in ___________________ Egg production and growth in ______________ Varieties of ________ improved food plants cattle crops poultry dog (note: fish and timber are still harvested from the wild, but the supplies are running low due to poor management of these resources)

19. Learning objectives: By the end of the lesson you should be able to: Describe the process of genetic engineering from the identification of a desired gene to the synthesis of the desired product.

20. 7: Genetic engineering Genetic engineering involves altering the genetic material of an organism. This can be done in two ways Altering or removing genes Adding genetic material from another organism

21. Using Genetic Engineering to modify bacteria

22. Using Genetic engineering to modify plants

23. Using Genetic engineering to modify animals

24. Result of genetic engineering Produces individuals ________________________ called _________________________ (GM) or transgenic organisms Has led to _____________ and ___________________ of medicines showing new characteristics genetically modified fasterlarger scale production

25. Learning objectives: By the end of the lesson you should be able to: State some of the medicinal products produced by genetic engineering. Describe the advantages and disadvantages of genetic engineering.

26. GM _______________ are used to produce the proteins needed by humans e.g. diabetics can now use human insulin produced by bacteria which have had the human insulin gene inserted into then. In the past diabetics had to use animal insulin bacteria

27. 8: Genetic engineering compared with selective breeding FeatureGenetic engineeringSelective breeding DNA can be introduced from ___________________ DNA only comes from ______________________ Advantages Genes Time Changes appear in the _________ generation Changes take _________ generations Offspring Will ________________ the improvement May or _____________ show the improvement any speciesone species next many definitely showmay not

28. Disadvantages FeatureGenetic EngineeringSelective Breeding Public Acceptance Safety People are ______________ of the new technology ____________________ of GM organisms The _________________ of producing new varieties _______________________ seen as safe suspicious accepted way concern over the releasenatural process