Evolution Flashcards
What is evolution?
•A gradual change in the inherited traits within a population over time.
•Occurs due to natural selection.
Outline the theory of natural selection
- Genetic variation exists due to spontaneous mutations.
- Competition between organisms
- A mutation may give an organism a selective advantage
- Organism is better adapted to the environment and survives
- Organism reproduces, passing on its beneficial alleles.
- Frequency of advantageous alleles increases
Why does competition between organisms in a habitat exist?
The resources within a habitat required for survival are limited
Give some examples of competition between animals within a habitat
Competition between animals for food, shelter, mates etc
Give some examples of competition between plants within a habitat
Competition between plants for light, water, minerals etc.
Describe the role of Darwin in the development of the theory of evolution by natural selection
•Studied a variety of organisms whilst travelling on the HMS beagle.
•Noted that traits can be passed from parents to offspring.
•Propsoed the idea of ‘survival of the fittest’.
•Established the theory of natural selection and published his ideas in ‘On the Origin of Species’.
Describe the role of Wallace in the development of the theory of evolution by natural selection
•Proposed a theory of natural selection that was similar to Darwin’s, although the mechanisms were different.
•Gathered greater evidence (e.g. studying warning colouration in butterflies) to support the theory.
How can the effect of camouflage on predator-prey populations be modelled?
- Take a piece of blue paper.
- Disperse an equal number of blue and white straws across the paper (straws represents prey populations).
- Set a stopwatch for 30s and instruct a volunteer to collect as many straws as possible (volunteer represents predator).
- Record the number of blue and white straws remaining.
- Repeat three times.
What is meant when a species is described as being extinct?
All members of the species have died
Why may some species become extinct? (3)
•Organisms not adapted to their environment.
•Organisms have not adapted rapidly enough to changing environmental conditions.
•Outcompeted by better adapted species.
Give some examples of modern day evolution
•Antibiotic-resistance bacteria
•Pesticide Resistance
•Warfarin-resistant rats
Describe how antibiotic resistance in bacteria illustrates the process of evolution
- Generic variation exists due to spontaneous mutations
- A mutation may give a bacterium antibiotic-resistance.
3.If an antibiotic is administered, the bacterium is better adapted and survives, whilst other bacteria is killed.
4.Bacterium reproduces, passing on its resistant variant
5.Frequency of antibiotic-resistant allele increases
Why is the development of antibiotic resistance in bacteria a good study for evolution?
Bacteria reproduce very rapidly, allowing the first-hand observation of evolution
Why are bacteria becoming increasingly resistant to antibiotics?
Due to over prescription and antibiotic misuse e.g. not completing the entire course
How can we reduce the spread of antibiotic-resistant bacteria?
•Prescribe antibiotics only when necessary.
•Ensure patients complete their antibiotic course.
•Reduce the use of antibiotics in farming.
•Improve hygiene in hospitals.
What is the genome?
The entire genetic material of an organism
What is the human genome project?
•Scientific research project involving thousands of scientists across the globe which successfully mapped the entire human genome.
•Scientists now aim to identify the function of every gene in the human genome.
How can the results of the Human Genome Project ve applied to medicine?
•Enables scientists to understand how lifestyle factors interact with genes- identifying predisposition to disease and possible preventions.
•Disease-carrying alleles identified more rapidly and the appropriate treatments prescribed earlier on.
•Scientists can predict an individuals response to certain drugs. New drugs can be developed which are tailored to a specific allele.
