Topic 4: Evolution & Genetic Engineering Flashcards
Who came up with the theory of natural selection?
Darwin
What is evolution?
The slow and continuous change of organisms from one generation to the next
What is natural selection?
The process by which a characteristic gradually becomes more or less common in a population
What is the process of natural selection?
- Species shows a wide genetic variation due to sexual reproduction and mutations
- There is a selection pressure (e.g. competition)
- Organisms that are better adapted to the selection pressures are more likely to survive and reproduce
- This passes on the desired and advantageous gene and they become more popular
- This is called survival of the fittest
What theory does antibiotic resistant bacteria support?
Darwin’s theory of evolution & natural selection
What is the process of how bacteria becomes resistant to antibiotics?
- Random mutations mean some bacteria develop allele for antibiotic resistance
- Resistance bacteria survive the antibiotic and reproduce
- Recessive allele become more common in the population
What are the three fossils that provide evidence for human evolution?
Ardi
Lucy
Turkana boy
How old is the Ardi fossil?
4.4 million years old
What feet does the Ardi fossil have?
Ape like big toe for climbing
What limbs does the Ardi fossil have?
Ape like (long arms, short legs)
What brain size does the Ardi fossil have?
Like chimpanzees
How old is the Lucy fossil?
3.2 million years old
What feet does the Lucy fossil have?
Arched for walking
No ape like big toe
What limbs does the Lucy fossil have?
Between human and apes
What brain size does the Lucy fossil have?
Bit bigger than chimpanzees
How old is the Turkana Boy fossil?
1.6 million years old
What feet does the Turkana Boy fossil have?
Human like (adapted for walking)
What limbs does the Turkana Boy fossil have?
Human like (short arms, long legs)
What brain size does the Turkana Boy fossil have?
Like humans
Where was the Ardi and Lucy fossil found?
In Ethiopia
Where was the Turkana Boy fossil found?
Kenya
What are the three ways to date tools?
- Rock layer - how much sedimentary was built on top of it
- Carbon dating - dates carbon containing material found within a took
- Structural features - if it’s simpler, it’ll most likely be older
What is the trend between how stone tools developed and the human brain size?
As human brain size increased, stone tools developed positively
How have stone tools developed?
- Simple pebble tools used to scrape meat and crack bones open - 2.5 million years ago
- Tools were sculpted from rocks were used to hunt, dig, chop and scrape meat off bones
- Flint tools - pointed to be used as arrowheads, fishhooks, needles etc. - present day
What is the pentadactyl limb?
Limb with five digits
How does the pentadactyl limb show evolution?
There are similarities in structure of pentadactyl limbs in different species e.g. humans and horses
Shows they all evolved from a common ancestor
What is Charles Darwin known for?
The theory of evolution by natural selection
When did Charles Darwin publish his theory? What is it called?
1859 - on the origin of species
How did Charles Darwin do his research?
Did a world expedition studying plants and animals
What were Charles Darwin’s three main observations?
There is variation within species
Individuals with characteristics are most suited to the environment they’re more likely to survive in
Characteristics can be passed on to offspring
What is Alfred Russel Wallace known for?
Coming up with idea of natural selection
What did Alfred Russel Wallace publish?
Joint writings with Darwin on evolution
What were Alfred Russel Wallace’s key observations?
There’s evidence for evolution by natural selection - e.g. some species may have warning colours to deter predators
What are the 3 ways in which natural selection impacted modern medicine?
- Classification - we now group organisms based on how closely related they are
- Antibiotic use - we now know how bacteria evolve to be antibiotic resistant, so we know to finish a course of antibiotics and to constantly develop new ones
- Conservation - we now know the importance of maintaining genetic diversity in species so they can adapt to changing environments
What is classification?
Organising living organisms into groups based on their features
What are the five kingdoms?
- Animals
- Plants
- Fungi
- Protists
- Prokaryotes
How to remember the five kingdoms?
Angry
Pans
Fry
Pea
Potatoes
What are the three domains?
Bacteria - true bacteria
Archaea - a different type of prokaryotic cells first found in extreme places
Eukarya - include protists, fungi, plants and animals
What comes first domains or kingdoms?
First, domains then kingdoms
Why are organisms classified the way they are now?
Genes can now be analysed
What is selective breeding?
Breeding plants or animals for particular characteristics
What are the steps of selective breeding?
- Select the organisms that most show the desired characteristic
- Breed the organisms together
- From their offspring, select those that demonstrate the desired characteristics the most
- Repeat over generations
Benefits of selective breeding?
Agriculture - crops and animals can be bred to produce bigger yields and better tastes
Medical research - organisms can be bred together to show a characteristics that’s being studied
Risks of selective breeding?
Less genetic variation in populations - could be wiped out by an environmental change more easily
Inbreeding occurs - can cause health problems
What is genetic engineering?
Transfer of a gene responsible for a desirable characteristic from one organisms genome into another organism
What is the process of genetic engineering?
- Cut the plasmid out of the DNA using lysosomes
- Cut the plasmid using restriction enzyme leaving behind complimentary sticky ends
- Insert the desired gene into the plasmid of the organism using ligase
- Insert the plasmid back into the organism
- The organism will then reproduce asexually and thus many cells are produced with the desired trait
Benefits of genetic engineering?
Agriculture - can make crops resistant to drought, pests or herbicides
Medicine - bacteria is used to produce human insulin - treats diabetes
Antibodies can be produced by sheep’s and cows
Risks of genetic engineering?
Some GM animals have health problems
GM crops could negatively affect food chains
What is the key example of the positive effects of genetic engineering we need to know?
INSULIN PRODUCING BACTERIA
What is biological control?
Using other organisms to reduce pest species
What are fertilisers?
Adding nutrients to soil
What are methods of increasing food production? Why are these necessary?
Biological control
Fertilisers
BECAUSE THE POPULATION IS RISING
Advantages of biological control?
Increases crop yield
Longer lasting effects than chemical pesticides
Less harmful to environment
Disadvantages of biological control?
New organisms introduced can cause problems e.g. become pests themselves
Advantages of fertilisers?
Increase crop growth
Disadvantages of fertilisers?
Can lead to eutrophication
What are the benefits of producing GMO crops?
GMOs can produce more nutrients
Can improve yields - e.g. GM drought- or pest-resistant crops
What is the example of a GMO crop that is pest resistant?
Bacillus thuringiensis (Bt) has a gene for toxin that kills insects
Bt inserted into crops through genetic engineering
Crops produced are now insect resistant - more food can be produced
What are the 3 main arguments against GMO crops?
Long term effects of GM crops are still unknown
Countries may be dependent on companies that sell GM seeds
People may not be able to afford food - poverty should be tackled first
What is the process of tissue culture in animals?
- Tissue sample from animal taken
- Cells are separated using enzymes
- Cells multiply in growth medium
- Cells are separated and grown in a culture vessel
Advantages of tissue culture in animals?
Medical research can be done in isolated tissues - no complications from other life processes
Process of tissue culture in plants?
- Parent plant with desirable characteristic is chosen
- Pieces of its tissue are removed from the root or shoot tip
- The tissue is put on medium containing growth hormones
- Growing plants are moved to soil trays
- Lots of clones of the parent plant are produced
Advantages of tissue culture in plants?
Plants with the same beneficial features are made quickly, all year, in a little space - no worry about conditions
