Darwin & Wallace & Evolution & Mendel & Development of Genetics

Who proposed the theory of evolution by natural selection?

Charles Darwin, with Alfred Russel Wallace independently developing similar ideas.

What observations led Darwin to natural selection?

Individuals within a species show variation; individuals with characteristics best suited to the environment are more likely to survive and reproduce; advantageous characteristics are then passed to offspring.

What book did Darwin publish?

On the Origin of Species in 1859.

Why was Darwin's theory initially controversial/not widely accepted?

It challenged contemporary religious ideas about the creation of species. -- There was insufficient evidence available at the time to convince many scientists. -- The mechanism of inheritance and variation was not yet understood.

What did Lamarck propose?

Characteristics acquired during an organism's lifetime could be inherited by offspring.

Why is Lamarck's explanation generally rejected?

We now know that, in the vast majority of cases, acquired characteristics are not inherited genetically.

What did Alfred Russel Wallace contribute?

Wallace independently proposed evolution by natural selection and produced important work on speciation and warning colouration.

How did Wallace influence Darwin?

Wallace's work led to joint writings with Darwin in 1858, encouraging Darwin to publish On the Origin of Species the following year.

What did Gregor Mendel investigate?

He performed breeding experiments on plants to investigate inheritance.

What did Mendel propose?

Characteristics are determined by inherited “units” (now known as genes) passed from parents to offspring unchanged.

Why was Mendel's work not initially recognised?

Scientists did not yet understand chromosomes, genes or DNA, so the mechanism explaining his results was unknown.

What was later discovered about chromosomes and Mendel's units?

Scientists observed that chromosomes and Mendel's inherited “units” behaved in similar ways, leading to the idea that genes are located on chromosomes.

What later discoveries supported gene theory?

The structure of DNA was determined and scientists worked out how genes function in protein synthesis.