Describe and example of how natural selection impacted the evolution of a particular species?

Question

Describe and example of how natural selection impacted the evolution of a particular species?

Answer 1

Snakes challenge nature vs nurture debate

Judy Skatssoon

ABC Science Online

Friday, 17 September  2004





Tiger snakes have adapted their head size to suit their prey

A study of how the size of snakes' heads change in response to the size of their prey has cast new light on the nature versus nurture debate.

An Australian and French study has showed that adaptability is a combination of genes and life experiences.

Research published in the latest issue of the journal Nature described a study of two separate populations of tiger snakes (Notechis scutatus).

The mainland population, found at Herdsman Lake in Western Australia, ate frogs and mice, and had small jaws.

The second population, on Carnac Island off the coast of Western Australia southwest of Fremantle, preyed on silver-gull chicks and had larger heads.

A team including the University of Sydney's Professor Richard Shine tested whether the different head sizes were the result of genetic mutations or a lifetime physical adaptation to the environment, known as adaptive developmental plasticity.

"There's been a scarcity of good examples of how these sorts of different ways of adapting to a challenge fit together," Shine said.

After capturing pregnant snakes from both populations and raising their offspring in laboratory conditions the researchers concluded that it was a bit of both.

The baby snakes were fed small or large mice. The mainland snakes heads remained small regardless of the size of their prey but the island snakes developed large heads.

"The mainland snakes are a population with a relatively small heads and regardless what happens to them in life they retain small heads," Shine said.

"The island snakes are not only born with large heads, they can get even bigger by having that plasticity; if they only have small prey they'll end up with pretty small heads but if they encounter large prey, rather remarkably ... they actually change the length of the bones in the head."

The study leads back to the question of what's most important: the genes you're born with or the experiences you encounter in life.

"What this is saying is that it's a combination of two," Shine said.

"Natural selection is actually able to make you plastic in ways that are likely to help you change in adaptive ways if you encounter unpredictable situations later on."

Answer 2

humans....many people are born without thumbs, but natural selection occured and since thumbs are a big part in surviving in life, the people with thumbs suvived

Answer 3

The pepper moth used to be mainly white with a few darker ones.  They lived in forests with trees with mainly white bark.  Then the industrial revolution occurred, coating the trees with soot, changing their bark darker.  Then the white moths got seen and eaten easier by predators, so more dark moths survived.  Evolution initially favoured the white type, but then the darker ones.  That was natural selection.

Answer 4

The Peppered Moth is a classic example of natural selection.  There was a rapid shift in the color of peppered moth populations during the 19th century in England. Before industrialism, speckled moths (lighter colored) had advantage because their coloring served to camouflage them. After industrialism, lichens on the trees died which made speckled moths visible. Darker moths were more likely to survive. This resulted in change in the allele frequency of the population.