science test 11 Darwin and natural selection

Charles Darwin

1809-1882, english naturalist, geologist and biologist, traveled around the world from 1831-1836 aboard HMS Beagle, developed the scientific theory of evolution by natural selection

The Peppered Moth during the Industrial Revolution in England

A prime example of natural selection and the process of microevolution in action. Due to the spread of pollution, likens and trees died out and trees became black with soot. Light colored moths died off due to predators because they stood out next to the blackened trees. Dark colored moths flourished because they could hide and blend into the dark trees therefor being hidden from birds/ predators. This example shows that as the environment changed, a specific organism's (dark colored peppered moth) chances of survival went up due to an adaptation (color variation) they had received.

Charles Lyell's contributions:

British geologist, followed up on Hutton's ideas. In 1830, e published the book "Principles of Geology". Lyell used geological evidence to describe geologic changes as the accumulation of very small changes over enormously long spans of time. Lyell thought the Earth was over 300 million years old. Darwin read and was greatly influenced by Lyell's writing.

Alfred Russel Wallace's contributions:

British naturalist, 1850s, friend of Darwin's though much younger. While working in the Malay Archipelago (Indonesia), Wallace developed a very similar idea about how living organisms evolve. The sharing of ideas with Darwin ultimately convinced Darwin to publish his own book "On the Origin of Species by Means of Natural Selection" in 1859.

what did Darwin observe in the Galapagos

Each of the Galapagos islands were unique in terms of its terrain, climate, vegetation, animal life. and animal life: animals uniquely adapted to life on each particular island (tortoise, mockingbird, finch)

Jean-Baptiste Lamarck's contributions:

French naturalist, 1800, theorized that living organisms adapt to their environment through sheer will and determination and that acquired traits developed during an organism's lifetime are passed to offspring.

scientists who influenced Darwin (HWLL)

Hutton, Wallace, Lamarck, Lyell

Darwin's voyage on HMS Beagle

In 1835, HMS Beagle visited the Galapagos Islands (600 miles off coast of Ecuador) for five weeks near the end of a five-year voyage of exploration around the world, Charles Darwin (age 26) was the ship's naturalist / biologist.

James Hutton's contributions:

Scottish geologist, 1788, noticed rocks at Siccar Point in Scotland and proposed that the Earth must be constantly changing and that it must be very, very old (much older than 6,000 years or so)

How evolution has modified living organisms to create new species:

Whale: first similar to big rat, slowly became amphibious, then became aquatic. Hind legs evolved into fins. Started as a mammal, therefore aquatic but breathes air. Horses: took 50 million years, transformed small dog sized forest dwelling Eohippus. Early ancestors walked on several spread out toes (in moist forest), large durable teeth, then greater speeds were necessary to outrun predators= lengthening limbs and placing bodies on 3rd toe (became hooves). Miohippus intermedius= new species (2nd/4th front toes long). Perahippus= North american animal size of small pony- prolonged skull/looked like horse of today-3rd toe carried main weight of body Galapagos tortoises: 2 different kinds, separated by each island. - Desert islands= has long neck, shell shorter so can eat fruit from cacti - Tropical environment= Short neck/big shell Galapagos finches: 15 different species - young finches (pink or yellow) - dimorphism in bill- - Darwin categorized them in songs - shorter bills- able to feed differently on favorite cactus-tear cactus base apart to eat pulp and larvi - Long bills- punch holes in cactus fruit and eat flesh

how did life on the islands influence Darwin's ideas of evolution and his book "ON THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION"

it made him question "could living things be changing (evolving) along with the islands?" (Prior, scientists believed life forms permanent/unchanging)

what are the 3 key components that natural selection is based on

overproduction, competition, genetic variation

why are the Galapagos geologically and biologically unique?

these islands are the result of tectonic hotspot activity, islands slowly move over time and as they move and interact with different ocean currents they develop unique environments (dry/barren vs lush/rainforest)