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
