evolution Flashcards
pneumonic for naming species
Keep Ppl Close Or Forever Go Solo
Kingdom
Phylus
Class
Order
Family
Genus
Species
Examples of environmental variation
Examples of environmental variation = scars, shades of skin tone
Examples of genetic variation
Examples of genetic variation = eye colour, nose shape, dimples
what feature in humans can be affected by both gender and enviroment
Height and weight can be affected by both gender and environment
who are the only genetically identical humans and why
Twins are the only genetically identical humans - as they are from the same zygote
what is Natural selection
Natural selection - when organisms gain an advantage and so become more likely to survive and breed
why does variation occur
Variation occurs due to inherited genes that arise through meiosis and sexual reproduction
what is the Theory of evolution
Theory of evolution: all species evolved form simple life forms that developed more than 3 billion years ago
summarise of the evolution process:
Summary of the evolution process:
1. individuals within a species show a wide range of phenotypes and genetic variations
2. those with characteristics better suited to the environment are more likely to survive and can pass on their alleles to the next generation
how do we know when a species has seperated
When two populations of one species become so different they can no longer interbreed to produce fertile offspring, they become two different species
what is selective breeding
selective breeding = breeding two organisms with desirable characteristics
what is selective breeding used for
Selective breeding is used for features like:
1. animals that produce more meat or milk
2. plants that lead to a higher yield
3. large, unusual, brightly coloured or heavily scented flowers
4. domestic dogs and farm animals with a gentle nature
limitations of selective breeding
Limitations:
1. the number of alleles in a population decreases greatly, decreasing variation, meaning they can’t survive in a change of environment (a new pathogen, a change in temperature) –> population can die out
2. Inbreeding = when populations are so closely bred that the animals are bred with close relatives –> reduces variation –> some breeds are particularly prone to diseases or inherited defects
what is genetic engineering
Genetic engineering = gene for a desirable characteristic is cut out of the cell of one organism and transferred to the cells of another
process for genetic engineering
Process of genetic engineering:
Enzymes are used to isolate and cut out a desired gene from an organism
Gene is inserted into a vector (bacteria plasmid/virus) using more enzymes
Vector is used to insert gene into desired cells
Genes are transferred to cells when they are at an early stage of development (egg or very early embryo in animals)
what can be made with genetic engineering
insulin and human growth hormones can be made with genetic engineering - there’s a limit to the proteins that bacteria can make
examples of GM crops
Genetically Modified crops (GM crops) can directly increase the size of a fruit or its nutritional value
Examples of GM:
potatoes have more starch and are resistant to common pests
2. soyabeans have a healthier balance of fatty acids
3. rice plants can withstand long periods of time in water
4. some grasses can absorb and break down explosive residue in soil
what is a clone
clone = an individual that has been produced asexually and is genetically identical to the parent
explain tissue culture
Tissue culture - a type of cloning:
use a mixture of plant hormones and conditions to stimulate each cell to form a new plant - it’s mostly used to preserve rare plants
They produce a mass of identical plant cells called a callus
explain embryo cloning
Embryo cloning:
give fertility hormones to a preferred cow - she produces many eggs
fertilise these with sperm from a preferred bull and once embryos have formed, wash it otut of the uterus
sometimes instead of implanting sperm, eggs are collected and fertilisation occurs in the lab
every cell in the embryo can be planted in a surrogate mother to become a cow –> (it is possible to do this as the cells are still unspecialised)
what is adult cell cloning
Adult cell cloning = A whole new animal is produced from the cell of another adult animal
what are the main steps to adult cell cloning
Main steps of adult cell cloning:
1. Nucleus is removed from an unfertilised egg
2. at the same time, a nucleus is taken from an adult body cell (e.g. - skin cell)
3. nucleus from adult cell is inserted into an empty egg cell
4. new cell is given a tiny electric shock –> this stimulates it to start dividing to form embryo cells which contain the same genetic info as adult
5. once embryo has developed into a ball of cells, it’s inserted into an adult female’s womb to continue development
what two ways can an animal be cloned by
an animal can be cloned by either : 1. dividing an embryo OR 2. cloning an adult cell
name an use of adult cell cloning
this method is useful to preserve endangered species
what is the problem with trying to use adult cell cloning to save an endangered species
Problem with this: In a natural population one or two can survive change, however with a cloned population, this is doubtful
name 4 Advantages of genetic engineering in agriculture:
Advantages of genetic engineering in agriculture:
1. improved growth rates of plants and animals
2. increased food value of crops –> GM crops have much bigger yields than ordinary crops
3. crops can be designed to grow in dry, hot and cold parts of the world
4. crops can make their own pesticide, or are resistant to herbicides used to control weeds
name 2 Concerns of genetic engineering in agriculture
Concerns:
1. effects of eating GM foods
2. genes from GM plants and animals may spread to wildlife in the countryside
what is a potential benefitc of genetic engineering
a potential benefit of genetic engineering is curing inherited diseases in embryos by putting healthy genes into infected cells
