Natural selection

Question 1

Evolution

Answer 1

gradual change in a species over time

Question 2

How did life begin?

Answer 2

with unicellular aquatic organims that lived over 3 billion years ago

Question 3

How do organisms evolve?

Answer 3

via natural selection

Question 4

Natural selection (basic definition)

Answer 4

In a species there is normally wide genetic variation. and this results in a range of phenotypes. THose organismsm that are best suited to their environment will survive and reproduce, passing on the advantageous characteristics through their genes. This process is repeated many times, which can eventually lead to the development of a new species.

Question 5

Is evolution a fast or slow process?

Answer 5

slow

Question 6

How have peppered moths come to be an example of evolution?

Answer 6

• Most peppered moths in Britain before the 19th century were pale coloured which allowed them to camouflage against trees.
• A mutation occurred in some moths which made then dark coloured and so they were easily seen by birds and eaten.
• During the Industrial Revolution many trees were covered in soot which meant the black moths were now more camouflaged and so more of them survives
• Eventually dark peppered moths became more common in urban areas than pale moths

Question 7

How does bacteria evolve to become antibiotic-resistant?

Answer 7

• Bacteria reproduce very rapidly and so can evolve within a short time frame.
• Occasionally the bacterium may have an advantageous mutation where it may cause resistance to an antibiotic.
• The bacterium will reproduce, passing on the antibiotic resistance while antibiotics kill the non-resistant bacteria.
• Eventually this will result in a whole species becoming antibiotic resistant.