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Biology Topic 6 Part 2 Inheritance, Variation, Evolution, Classification
Biology Topic 6 Part 2 Inheritance, Variation, Evolution, Classification
Genetic Inheritance
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Inherited disorders
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Cystic fibrosis
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can cause respiratory issues and digestive problems due to the mucus. Digestion issue can lead to limited nutrient uptake and developmental issues
Treatment - physio to alleviate the blocked airways caused by mucus
Medication antibiotics to prevent infections on respiratory system
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EVOLUTION the change in inherited characteristics of a population over time through a process of natural selection
Variation
Overproduction
Struggle
Survive
Advantage
Gradual
Charles Darwin's theory
Make sure you can describe the process of natural selection - the organisms that are best suited to the environment they are in will be the ones to survive
Variation
Evolution - a change in the inherited characteristics of a population over time by natural selection - leading to gradual change.
Variation - differences in a population
overproduction - more offspring produced to ensure survival
Struggle offspring struggle and compete for resources
Survive best suited offspring will survive
Advantage offspring survive to reproductive age and pass on genes to next generation
Gradual over time the genes present in the population will shift to those for characteristics that are better suited to the environment
Selective Breeding this is the artificial process where humans breed plants or animals for particular desirable characteristics. They do this over many generations to develop the desirable characteristics.
-Select parents with the characteristics you want
-breed them
-choose the offspring that show the desired characteristics
-repeat
Genetic engineering-This is the process of modifying the genome of an organisms by introducing a gene from another to give a desired characteristic
Examples - bacterial cells genetically modified to produce human insulin
process
gene that codes for the required characteristic/protein are cut out (using enzymes)
Gene inserted into a vector (usually a plasmid)
Vector inserted into required cell
Genes transferred into cells in early development
Variation - can be genetic or environmental Genetic - only 4 truly gene controlled characteristics - eye colour, natural hair colour, blood groups, genetic diseases. Other characteristics can be a combination (weight) or purely environmental (e.g. language/accent)
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examples of selective breeding - disease resistance in crops, meat production/milk production in animals, flower scent/colou
Problems with selective breeding - can cause "inbreeding"
Reduce the variation in the genes available which can lead to inherited defects becoming more common - deafness in Dalmatians, breathing problems in pugs/bull dogs
examples - insulin production by bacterial cells, crops resistant to insect attack, crops to increase yield
Genetic Engineering concerns - that modified plants could pose threat to wild insects/plant life. Possible side effects of eating GM foods not fully researched
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