4) Natural Selection & Genetic Modification Flashcards
What does the theory of natural selection propose?
All species have evolved from simple life forms
What is involved in the process of natural selection?
Genetic variation
Survival of the fittest
Successful breeding
Best characteristics survive
What factors contributed to the slow acceptance of natural selection?
Religion
Inconclusive evidence
Genes yet to be discovered
What did genes not being discovered mean?
Darwin was unable to suggest why characteristics were passed down
What did both Wallace and Darwin have?
Island research
Joint writings
Competition
When did Wallace and Darwin produce joint writings?
1858
What is evolution defined as?
The gradual change of inherited characteristics of biological populations over time
What is evolution usually driven by?
Natural selection
What evidence is there for evolution?
Antiobiotic resistant bacteria
Fossils
How do doctors reduce new resistant strains of bacteria?
Avoid prescribing antibiotics unncessarily
Patitnets finish a course of antibiotics so all bacteria is killed
Antiobiotics in agriculture should be restricted
How do resistant strains of bacteria spread?
Mutated pathogens are resistant to antibiotics and will survive and reproduce creating bacteria which is also resistant
How many digits do animals with pentadactyl limbs have per limb?
5 digits
What are the 3 ways of forming fossils?
Preservation when decay is not possible
Mineral replacement
Hardening soft materials
How do hardening soft materials create fossils?
Hardening of soft materials can produce casts or impressions
How does mineral replacement create fossils?
Hard parts of organsisms are gradually replaced by minerals as they decay slowly creating a rock liek substance
Why is the fossil record incomplete?
Lots of early life forms were soft bodied
Geological activity has destroyed traces of ancient life
What are the oldest fossilised human remains?
Ardi (4.4 million years ago)
When was Lucy found?
3.2 million years ago
When was Leakey found?
1.6 million years ago
What do tools tell us about how evolved humans were?
More compex tools = more developed brain
What does carbon dating tell us?
When a rock was originally formed
How do you determind when a stone tool was in use?
Determine how deeply it was buried
Use known dates of other items at that level
Compare the design to other stone tools already dated
What were the 7 groups in the Traditional classification system?
Kingdom Phylum Class Order Family Genus Species
What does the 3 domain system classify organisms by?
Chemical analysis
What are the 3 domains?
Archaea
Bacteria
Eukaryota
Who proposed the 3 domain system?
Carl Woese
What did Linnaeus categorise organisms by?
Their structure and characteristics
What is the genus of Canis lupus?
Canis
What are archaea?
Primitive bacteria
What are eukaryota?
Organisms that possess complex subcellular structures
How do scientists show how they believe organisms are related?
Evolutionary trees
What does DNA sequencing tell us?
How closely related different species are
What defines a species?
Individuals that breed ogether to produce fertile offspring
What is speciation?
How a new kind of plant or animal species is created
What are the types of selection?
Stabilising
Directional
Artificial
What is directional selection?
Natural selection that favours an extreme phenotype
What is stabilising selection?
Natural selection that favours the average phenotype
When does selective breeding happen?
When humans choose animals and crops to breed based on their genetic characteristics
What are the processes of selective breeding?
1) Breed parents with desired characteristics
2) From offspring choose offspring which display desired characteristic
3) Breed chosen offspring
What type of selection is natural breeding?
Artificial selection
What are dangers of selective breeding?
Reduced variation
Inbreeding
What are inbred animals more susceptible to?
Disease
Inherited defects
What agricutural term is used to describe food production productivity?
Yield
What does tissue culture do?
Grow genetically identical cells in a lab under sterile conditions
What are the stages of tissue culture?
1) Tissue sample taken from plant
2) Cells sterilised
3) Sample treated with hormones to trigger cell division and grown on an agar plate
4) Callus (ball of cells) forms and more hormones are added to cause roots and stems to grow
5) Plants can be planted in soil
What are uses of tissue culture?
Medicine
Plants
How is tissue culture used in mediicne?
Study cell processes and drug effectiveness
Study viruses that cannot live outside cells
Grow artificial tissue for transplants
How is tissue culture used with plants?
We can produce lots of genetically identical plants quickly
Any time of the year in a lab
Increase population of rare species
What does genetic engineering involve?
Modifying an organism’s genome by introducing a gene from another organism to produce the desired characteristic
What can a lack of vitamin A lead to?
Blindness
What are examples of genetic engineering?
Vitamin A rice
Insulin-producing gene
What are the stages of genetic engineering?
1) Restriction enzymes ‘cut’ a desired gene out of a chromosome
2) Restrction enzyme cuts a vector, both target gene and vector have exposed ‘sticky ends’
3) Ligase enzyme joins sticky ends so vector carries target genes. Marker gene added to vector to make it easy to check if vector has taken up target gene
4) Gene is delivered into cells by vector before they have differeniated and all cells in developed organism will have the same gene
What enzyme is used to join sticky ends?
Ligase
What is the name of the sections of single-stranded DNA produced when restriction enzymes cut DNA?
Sticky ends
What are uses of genetic engineering?
Transferring genes into bacteria
BT insect resistance
Transferring genes into animals
Transferring genes into plants
What does GM stand for?
Genetically modified
What are GM crops engineered to have?
Resistance to diseases, insects, or herbicides
Production of larger fruit
What is BT insect resistance used to do?
Crops kill insects without the need for insecticides are BT is toxic to many insects
What are advantages of genetic engineering?
Preventing inherited diseases
Improving food production quality
What are advantages of GM crops?
Increased yields
Provide more nutrients
What does golden rice help to treat?
Vitamin A deficiency
What are concerns of genetic engineering?
Uncertain long term effects
Some consider it unethical
What are disadvantages of GM crops?
Reduced biodiversity
May be long term effects on human health
If transplanted genes escape, ‘superweed’ could be created
