B13/ B14 Variation, Genetics And Evolution Flashcards
What are the slight differences of an organism called
The variation of a species
What is selective breeding
humans artificially selecting the plants or animals that are going to breed so that the genes for particular characteristics stay in the population
Give 4 examples of features that are useful or attractive for selective breeding
Animals that produce meat or milk
Crops with disease resistance
Dogs with a good gentle temperament
Decorative plants with big unusual flowers
Give the 4 basic steps of selective breeding
From your existing stock, select the ones which have the characteristics you want
Breed them with each other
Select the best of the offspring and breed them together
Continue this process over several generations and the desirable traits will get stronger and stronger and eventually all the offspring will have the characteristic
In agriculture what can selective breeding be used to improve
To improve yields e.g. meat yields, crop yields
How old is selective breeding
Thousands of years old. Not new at all
What is the main drawback of selective breeding
A reduction in the gene pool
What is a gene pool
The number of different alleles in a population
What is inbreeding
Where the offspring breed together
Why can inbreeding be bad and why
Can cause health problems because theres not much variation in the population. All the stock are closely related to eachother so if one of them will be killed by disease the others are likely to die too
What does selective breeding reduce (negative)
Reduces chance of any resistant alleles being present in the population
What does genetic engineering do
Transfer genes between organisms
What are the 3 steps of genetic engineering
A useful gene is isolated from one organisms genome using enzymes and is inserted into a vector
The vector is usually a virus or a bacterial plasmid depending on the type of organism that the gene is being transferred to
When the vector is introduced to the target organism the useful gene is inserted into its cells
What has bacteria been genetically engineered to produce and why
To produce insulin that can be used to treat diabetes
Why have GM (genetically modified) crops had the genes modified
To improve the suze or quality of their fruit to make them resistant to disease, insects and herbicides
Why have sheep been genetically engineered
To produce substances, like drugs in their milk that can be used to treat human diseases
What is gene therapy
A technique that modifies a person genes to treat or cure a disease
Why is it good for genetic engineering to happen at the early stages of the receiving genes development
So the organism develops with the characteristic coded for by the gene
Why is genetic engineering a controversial topic
There are worries about the long term affects of genetic engineering - that changing an organisms genes might accidentally create unplanned problems which could get passed on to future generations
What are 3 negatives of GM crops
Growing GM crops can affect the number of wild flowers that live in and around the crops reducing the farmlands biodiversity
GM crops may not be safe and we dont yet fully understand the effects of eating them on human health
Transplanted genes may get out into the natural environment creating new bad varieties
What are 3 positives of GM crops INCOMPLETEEDD
The characteristics chosen fir GM crops can increase the yield, making more food
GM crops can be modified to include the nutrient that is missing in a developign country that is lackign a certain nutrient
What is classification
The organisation of living things into groups according to their simailarities
Why do biologists classify organisms
So they can understand how different groups of living things are related to each other enabling scientists to recognise the biodiversity present in the world and gives scientists a common language in which to talk about
What is an evolutionary (phylogenetic) tree
A model which shows how scientists think different organisms are related
