Section 4 - Natural Selection and Genetic Modification Flashcards
Natural selection and evidence for evolution, fossil evidence for human evolution, classification, selective breeding, genetic engineering
MRSA is a bacterium that is resistant to antibiotics.
What does this mean?
The bacteria cannot be killed by antibiotics
Why can bacteria evolve rapidly?
bacteria reproduce at a fast rate
What is meant by ‘natural selection’?
Individuals with characteristics that make them better adapted to the selection pressures in their environment have a better chance of surviving and reproducing successfully. This means the alleles that are responsible for the useful characteristics are more likely to be passed on to the next generation.
Describe how a population of bacteria can become resistant to a particular antibiotic.
Bacteria can develop random mutations in their DNA that make them resistant to a particular antibiotic. Antibiotic resistant bacteria are more likely to survive and reproduce, passing on the gene for resistance. The gene for resistance becomes more common in the population due to natural selection.
True or false? The movement of rock layers can affect the accuracy of dating stone tools.
True. Dating stone tools using stratigraphy can be inaccurate if the rock layers have moved over time.
Apart from stratigraphy, give one other method of dating stone tools.
Stone tool found with carbon-containing material
e.g. a wooden handle, can be dated using carbon-14 dating.
Which scientist organised the expedition that found the 1.6 million year old Homo erectus called ‘Turkana Boy’?
Richard Leakey
True or false? ‘Turkana Boy’ is older than the fossil skeleton of ‘Ardi’.
False. The fossil skeleton of ‘Ardi’ is 2.8 million years older than that of ‘Turkana Boy’
Give ways in which ‘Lucy’ is different from ‘Ardi’
‘Lucy’ didn’t have an ape-like big toe, ‘Ardi’ did.
The size of Ardi’s arms and legs were more like an ape than a human, while the size of Lucy’s arms and legs were between what you would expect to find in apes and humans. Lucy had a larger brain. The structure of Lucy’s leg bones and feet suggests that she walked upright more efficiently than Ardi.
What does classification mean?
The organisation of living organisms into groups
Name the five kingdoms traditionally used in classification.
animals, plants, prokaryotes, and protists
Archaea are one of the three domains proposed for use in classification instead of the five kingdoms. Name the other two.
bacteria and eukarya
What type of organisms are in the domain Archaea?
Prokaryotes
How can the genes of an organism be used to determine how closely related it is to other organisms?
The sequence of DNA bases in the genes can be determined, and then the sequence can be compared to other organisms. Those with more similar DNA sequences are more closely related to each other.
Explain how developments in technology have lead to the proposal of splitting the Prokaryote kingdom into two domains
Developments in technology have led to the use of RNA sequencing. This has been used to show that some members of the Prokaryote kingdom were not as closely related as first thought, leading to the proposal that the animal kingdom should be split into separate groups.
