4.1B **Biology Only** - Darwin and Wallace’s Theories and 4.2 - Evolution by Natural Selection Flashcards
Who developed the theory of speciation?
Alfred Russel Wallace developed the theory of speciation and therefore evolution by natural selection.
What idea did Wallace have regarding survival in changing environments?
Wallace believed that individuals without characteristics to help them survive a change in the environment would die out.
With whom did Wallace publish joint studies?
Wallace published joint studies with Charles Darwin.
What was the significance of the publication of ‘On the Origin of Species’?
The publication meant that Darwin received the credit for the theory of evolution.
What was one of Wallace’s important works?
One of his most important works was on warning colouration in animals.
What is the first step in the process of speciation?
Variation exists within a population as a result of genetic mutations.
What happens to alleles that provide a survival advantage?
Alleles that provide a survival advantage are selected for through natural selection.
How can populations of a species become isolated?
Populations can become isolated through physical barriers, such as a rock fall preventing them from breeding together.
What may happen to alleles in a new environment?
Different alleles may be advantageous in the new environment, leading to them being selected for.
What occurs over time between two isolated populations?
The selection of different alleles will increase the genetic variation between the two populations.
What indicates that a new species has formed?
A new species has formed when the populations are no longer able to breed together to produce fertile offspring.
Who was Charles Darwin?
Charles Darwin was a scientist and naturalist who put forward the theory of evolution.
What supported Darwin’s theory of evolution?
Darwin’s theory was supported by experimentation and his knowledge of geology and fossils.
When was ‘On the Origin of Species’ published?
‘On the Origin of Species’ was published in 1859.
What is the theory of evolution?
The theory of evolution states that variation exists within species as a result of mutations in DNA.
What is meant by ‘survival of the fittest’?
Survival of the fittest means that organisms with characteristics most suited to the environment are more likely to survive to reproductive age and breed successfully.
What happens to beneficial characteristics over generations?
Beneficial characteristics are passed on to the next generation, increasing the frequency of alleles for these characteristics within the population.
What was one reason for the controversy surrounding Darwin’s ideas?
One reason was that it contradicted the idea that God was the creator of all species on Earth.
What was a limitation of evidence at the time of Darwin’s theory?
There was not enough evidence at the time as few studies had been done on how organisms change over time.
What was not known at the time regarding inheritance?
The mechanism of inheritance and variation were not known at the time.
