Topic 4 - Natural selection and Genetic Modification Flashcards
Define ‘Evolution’
An organism developing over generations to adapt to its environment in order to survive (natural selection)
Describe how binomial species names work
It goes the genus then the species second
How does evidence from fossils and stone tools support ideas about human evolution?
When we lay them out in chronological order we can see the gradual changes as they advance through their structure features becoming more complex over time. Or how their bond features change.
How can we date stone tools?
Carbon-14 dating
Stratigraphy - study of rock layers- deeper = older
Describe how stone tools have developed over time
2.5 million - simple stone tools called people? tools by hitting rocks together - scrape meat
2 million - sculpted more complex tools to hit with eg azes
300,000 - more complex tools spears and flint
200,000 - Flint tools, pointed arrowheads
Name the fossil hominids in chronological order
Ardi - 4.4 million - climb trees, more ape like, chimp brain size
Lucy - 3.2 million - Arched feet for walking, slightly larger brain, more upright
Leakey’s turkone boy - 1.6 million, more human than ape, larger brain, more upright than Lucy
What is the cause of genetic variation?
Change in an organisms alleles which arise due to mutations
Why do adaptations allow organisms to survive?
and what is natural selection
They become more adapted to the conditions in their environment meaning that they can survive. This is called ‘Natural Selection’.
How does natural selection allow some members of species to survive better than others?
Ones that have better characteristics for their conditions survive longer than others do (survival of the fittest)
How does natural selection lead to the evolution of new species?
Over many generations as one species evolves it becomes a new species adapted for its environment.
How does development of resistance in organisms support Darwin’s theory?
An organism can become for example resistant to pesticides if it’s a bug which supports evolution as it has adapted to survive the impact.
What are the names of scientists who developed first ideas of evolution?
Charles Darwin and Alfred Russel Wallace
What evidence supports their theories and what are their theories?
Wallace - Animals have warning colours to deter predators as an example of beneficial characteristics showing evolution
Darwin - Variation noticed in some species meaning they are more suited to survive in their environment
What was the impact of the Theory of Evolution on modern Biology?
- Classification - we can now classify organisms into groups based on how closely related they are
- Antibiotic resistance - we understand importance of finishing a course of drugs to prevent bacteria spreading and new antibiotics to fight newly evolved bacteria.
- Conservation - Importance of genetic diversity and how populations adapt to changing environments and has led to conservation projects.
What is a pentadactyl limb and how does it provide evidence for evolution by natural selection?
Limb with 5 digits shows evidence for common ancestor but we have evolved for different adaptations eg bat wing or human hand
How are organisms classified into smaller groups?
Based on their common features, organisms are separated into 5 kingdoms then the phylum, class, order, family, genus, species
What are the five kingdoms?
Animal, Plant, Fungi, Prokaryotes, Protists
What is genetic analysis?
Being able to read someone’s genome (all genes and base sequence)
What are the 3 domains we now classify organisms into?
Archaea, Bacteria, Eukarya
- Archaea = found in extreme places eg hot springs and salt lakes, look like bacteria
- Bacteria = true bacteria, prokaryotic
- Eukarya = broad range eukaryotic : fungi, plants, animals and protists
How are new breeds and varieties created? And why?
Through selective breeding, selectively breed to develop features making it more useful and attractive eg animals more meat and milk, dogs with good temperament, crops with disease resistance, plants bigger fruit
What is a genetically modified organism?
An organism you change the base sequence of the DNA to become for example, resistant to insects or increase food production.
How is selective breeding carried out?
Select best characteristics you want and two organisms with this phenotype and breed them. Then select best offspring and breed them together. Continue over several generations so all offspring have characteristics eg edible crops from wild plants over thousands of years
What are the impacts? (Positive and negatives)
\+ better characteristics \+ can help investigate alcoholism - reduces gene pool - leads to inbreeding health problems - new disease appears populations can be wiped out
How is tissue culture carried out?
1) Take plant you want to clone based on characteristics
2) Remove tissues from parent plant from short tips of fast? root
3) Grow tissue in growth medium containing nutrients and growth hormones under aseptic conditions to prevent microbes getting in
4) Remove to potting compost to carry on growth
Why does it produce many identical cells?
Because they are genetically identical clones of the parent cell
What are the advantages of tissue culture in medical research?
- You can carry out experiment on the tissue culture in isolation so you don’t need to test drugs on animals
- Look at effects of particular substance or environment change on a single culture without processes in whole organism
What are the advantages of tissue culture in plant breeding programmes?
You can get lots of clones of a larger fruit so whole population is larger
What are the main stages of genetic engineering?
1) DNA you want to insert is cut with restriction enzyme
2) Vector DNA cut open using same restriction enzyme
3) These two DNA’s (Vector’s DNA and DNA) are left with sticky ends and are mixed together with ligase enzymes
4) Ligase sticks ends together to make recombiant DNA
5) The recombiant DNA is reinserted into other cells
6) These cells now use the gene you inserted to make the protein you want
Name some selectively bred organisms in agriculture and medicine
- Crops resistant to herbicides - this means then resistant to weedkillers
- bacteria to produce insulin
What are the benefits of using selective breeding and genetic engineering to produce new varieties and breeds and risks?
\+ higher yields \+ chosen characteristics - decreases biodiversity - decreases gene pool - can leak into wildlife
What are some useful GMO’s?
Resistant to insecticides Bt toxin inserted to make resistant to insecticides however soon insects could become resistant so farmers should use multiple ones
How can GMO’s increase crop yield?
Pests can be controlled with pesticides
Crops can be genetically engineered to be grown better in drought conditions
Golden rice has been GE’ed to convert to Vitamin A
How can GMO’s cause problems in environment?
Pesticides/pest resistant plants can get into environments and could kill natural pests in their habitats therefore decreasing biodiversity
What is biological control? (Advantages)
Using methods to reduce pest numbers
Has longer lasting effects and less harmful
Why do we need to produce more food?
Because we have a growing population
How can Biological control increase crop yield?
Biological control can introduce an animal to act as a predator to get rid of pests that damage crops increasing crop yield.
For example, cane toads were introduced to Australia to get rid of beetles.
What are the negatives of introduction of cane toads?
Cane toads are now a pest themselves as they poison native toad species that eat them.
Decrease biodiversity
Why do fertilisers increase crop yield?
They contain minerals essential for plant growth so we have access to enough food. They replace nutrients that are lost from the soil from the last crops.
Why are fertilisers bad for the environment?
They can leak into nearby streams and rivers and cause eutrophication, killing fish species.
