Unit 4 Revision Flashcards
State the pros for Gm crops
Farmers have a higher yield
Less deforestation
Less costs on pesticides
State the cons of Gm crops
Less pollination
Reduction in biodiversity
Potential health issues
Not natural (ethical reasons)
What is tissue culture ?
Used for cloning plants and reproducing cells in a sterile environment
Why is tissue culture a preferred way of cloning plants over cuttings?
It is quicker, more efficient, ,produces more at once (bigger yield)
What is a eukaryotic cell
A cell that has a nucleus
Wha is a prokaryotic cell
A cell that doesn’t have a nucleus
What is selective breeding
A farmer picks organisms with desirable features to breed
Explain how natural selection works
There is variation within population, within the population the strongest survive. The strongest breed more often and pass on genes more frequently.
(Give example)
Describe how the skull size of humans ancestors has changed over time,
State the names of each ancestor in your answer as well as how long ago it was….
The size of the human skull has increased. The smallest starting with the ardi (4.4m) lucy (3.2m) homo habilis(2-1.5m) homo erectus (500,000) and then lastly the homo sapien- the biggest and present state.
Define evolution
Evolution is how species of living organisms have changed over geological time
How are stone tools dated from their environment
Stone tools are dated by the age of the rock they are found in, NOT the age of the actual stone they are made from.
Name the human like species skulls that e rI found along side their dates
Ardi- 4-4.5m Lucy-2.5-3m Homo habilis-1.8-2m Homo erectus-1.5m Homo sapiens-present skull & 100,000 years ago
Cause of genetic variation
Mutations
Environmental factors
How can natural selection lead to the evolution of a new species
If an organism in a species had a mutation that benefited it in it’s environment it will successfully pass on these genes and the offspring will have the benefit as well
How does the development of resistance in organisms support darwins theory
Microorganisms such as bacteria and viruses reproduce rapidly and can evolve In a relatively short time.
Consequently if a bacteria let’s say had a mutation when being produced, this mutation could protect them against certain antibiotics. This would then be passed down therefore causing resistance.
Names of scientists who first developed the idea of evolution by natural selection
Charles Darwin
Alfred Russel Wallace
What is the pentadactyl limb and where is it found and how does it provide evidence for evolution
Many vertebrates have a similar bone structure despite their limbs looking different on the outside. It is A limb with 5 digits (fingers) such as a human hand or foot, it suggests that many vertebrates descended from the same common ancestor.
How are organisms classified into smaller groups based on their characteristics
Classification of living things ;
Kingdom Phylum Classes Order Families Genus Specials
What are the 5 kingdoms
Monera Protist Fungi Plant Animal
What are the three domains
Archaea
Bacteria
Eukarya
Why are new breeds and varieties being created
By natural selection
Selective breeding
What is meant by a genetically modified organism
A gmo is an organism whose genome has been altered by the techniques of genetic engineering so that it’s DNA contains one or more genes not normally found there.
How Is selective breeding carried out
A human takes organisms with favourable traits and breeds them so those traits can be produced and made again
Effects of selective breeding
Less variation within population
Disease is more likely to affect more of the organisms if they all share a similar genome
How is genetic engineering done
- bacteria example -
The human cell contains the gene for insulin, this gene is isolated. A bacterium cell contains a plasmid. The gene for insulin is removed from the Human cell by restriction enzymes, the plasmids is removed from the bacterium by restriction enzymes.
These enzymes cut the plasmids and create sticky ends; bases that don’t match. The insulin gene is then inserted into the plasmid by ligase enzymes which creates a vector. The bacteria then multiply and the insulin protein is created
Uses of genetically engineered organisms
In medicine genetic engineering has been used to mass produced insulin, human growth hormones and vaccines. In agriculture it has been used to produce desired traits e.g. - drought tolerance and pest resistance
Benefits and risks of using selective breeding and genetic engineering
Higher yield of goods Healthier animals More desirable traits But Reduces variation Playing god Disease risk
How can crop plants become modified to make them resistant to insect pests
Genetically modified to be toxic to certain pests
Advantages and disadvantages of GM
Higher yield
Resistant crops
Could harm people if chemicals have been used
Expensive
What is biological control
The control of a pest by the introduction of a natural enemy or predator
How can biological control cause problems
Can have unknown ecological effects- the opposing natural enemy could cause more problems.
Research and development costs can be high
Decreases biodiversity
How can fertilises damage the environment
Causing pollution by the mass of fumes being given off by the crops.
Pollute water supplies
What is genetic engineering
Modifying the genome of an organism to introduce desirable characteristics
Describe the work of Darwin and Wallace in the development of the theory of evolution by natural selection and the impact of these ideas on modern biology.
Charles Darwin and Alfred Russel Wallace went to the Galapagos islands in 1835, it helped Darwin formulate his ideas on natural selection, he saw animals of the same species but of different adaptions eg- different size beaks on finches and how this could effect their food source.
Explain Darwin’s theory of evolution by natural selection
More individuals are being produced each generation that can survive. Phenotypic variation exists among individuals and they are heritable. Those individuals with heritable and desirable traits will be more suited to the environment and will survive
What is Bacillus Thuringiensis and uses of it in crop plants
This bacteria naturally produces a toxin which is poisonous to many insects, the gene for producing this poison has been inserted into crop plants which are now resistant to these insect pests.
Advantages and Disadvantages of using Bacillus Thuringiensis
Advantages- less insecticide (chemicals to kill insects) has to be used and crop yield is higher.
Disadvantages- Toxin could kill other, harmless insects, the gene could be transferred into other wild plants and some insect species have already evolved resistance to the toxin
