Natural Selection & Evolution (Edexcel GCSE Biology)
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True or False?
Charles Darwin and Alfred Russel Wallace came up with different ideas relating to the theory of evolution.
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True or False?
Charles Darwin and Alfred Russel Wallace came up with different ideas relating to the theory of evolution.
False.
Darwin and Wallace independently came up with the same ideas relating to evolution.
What is the name of the theory put forward by Charles Darwin and Alfred Russel Wallace?
The theory put forward by Charles Darwin and Alfred Russel Wallace is the theory of evolution by natural selection.
How has the work of Darwin and Wallace impacted modern biology?
Impacts of Darwin and Wallace's work on modern biology include:
classification can now be done on the basis of evolutionary relationship
conservationists know that it is important to preserve genetic variation so that populations can adapt to change
microbiologists understand how antibiotic resistance develops and can take steps to reduce the risks
True or False?
Natural selection can occur in a population of genetically identical individuals.
False.
Natural selection can only occur when genetic variation is present. This is why populations with no, or limited, genetic variation are unable to adapt to changes in their environment.
Describe the process of natural selection.
The process of natural selection states that:
individuals within a species exhibit variation due to genetic differences
reproduction in populations produces many offspring
there is competition for resources within populations, resulting in a struggle for survival
those with advantageous traits are more likely to survive and reproduce, passing on their advantageous alleles to the next generation
What is antibiotic resistance?
Antibiotic resistance is the ability of bacteria to withstand the effects of an antibiotic; bacteria with resistance to a particular antibiotic are more likely to survive when they are exposed to the drug.
True or False?
Mutation can result in antibiotic resistance in bacteria.
True.
Random mutations in bacterial DNA can lead to antibiotic resistance, enabling some bacteria to survive antibiotic treatment.
How do antibiotic resistant strains of bacteria arise?
Antibiotic resistant strains of bacteria can arise by natural selection as follows:
mutation gives rise to an allele that codes for antibiotic resistance in one individual
the resistant individual survives when treated with the antibiotic
the individual reproduces and passes on the resistance allele
this occurs over many generations until only resistant individuals remain
How does the development of antibiotic resistance provide support for Darwin's theory of evolution by natural selection?
The development of antibiotic resistance provides support for Darwin's theory of evolution by natural selection because it shows natural selection in action during a short time period.
Bacteria have a short life cycle, so any favourable characteristics that aid survival are passed on very quickly, allowing natural selection to be observed.
True or False?
The fossil named Ardi provides information about human evolution from within the last 1 million years.
False.
The fossil Ardi is 4.4 million years old, so provides information about human evolution 4-5 million years ago.
What are the differences between the fossil Ardi and modern humans?
Differences between Ardi and modern humans include:
Ardi has an ape-like big toe
Ardi's legs are shorter than human legs
Ardi has longer arms than humans
Ardi's skull shows that her brain would have been closer in size to a chimpanzee than a human
How is the fossil Ardi similar to modern humans?
Ardi is similar to modern humans in that the evidence suggests that Ardi walked upright:
pelvis and leg structure are human-like
hand structure suggests they were not used for walking
How old is the fossil Lucy?
The fossil Lucy is 3.2 million years old.
What is the evidence that Lucy evolved more recently than Ardi?
The evidence that Lucy evolved more recently than Ardi includes:
Lucy is a younger fossil
Lucy has arched feet that are similar to humans
Lucy does not have an ape-like big toe
Lucy's limbs are more similar in length to humans than Ardi's
Lucy's skull suggests a larger brain than Ardi
Lucy's upright posture would have allowed more efficient walking than Ardi's
True or False?
The 1.6 million year old skeleton found by Richard Leakey provides evidence that humans evolved in Asia.
False.
The 1.6 million year old skeleton found by Richard Leakey was discovered in Kenya, so provides evidence that humans evolved in Africa.
How can the age of stone tools be determined?
The age of stone tools can be determined as follows:
rocks form in layers, so tools that correspond to more recent rock layers will be younger
carbon dating of tools that contain carbon
What do discoveries of stone tools show about human evolution?
Stone tools show how human-like ancestral species have become more intelligent over evolutionary time; more recent tools tend to be more advanced, indicating the evolution of more complex brain function.
What is the name given to the type of structure shown?
The type of structure is the pentadactyl limb.
How does the pentadactyl limb provide evidence for evolution by natural selection?
The pentadactyl limb provides evidence for evolution by natural selection because pentadactyl limbs in different species that are adapted for very different purposes all share the same basic structure. This indicates that they have all evolved from a common ancestor.
What are the three domains of classification?
The three domains are:
archaea
bacteria
eukarya
True or False?
The three domain system of classification relies on evidence from microscope analysis of cells.
False.
The three domains system is based on information from chemical analysis, e.g. DNA sequencing.
How has DNA analysis led to the proposed three domain system of classification?
DNA analysis has led to the three domains system because it has shown that the DNA of the archaea is more similar to the DNA of the eukaryotes than it is to the rest of the prokaryotes.