Natural Selection And Genetic Modification Flashcards
Who proposed that humans had evolved from monkeys or apes?
James Burnett, Lord mondoddo but most people thought he was mad
What is evolution?
It’s a gradual change in characteristics of a species over time. scientists use fossils to find out about human evolution. They work out how old fossils are and out then in age order, the fossils do not show smoothie changes over time because some are undiscovered
In 1992 what did scientists discover?
4.4 million year old fossilised bones from a female of an extinct human-like species. More fossils of this species were found and named Ardipthecus ramidus. Most complete set of these fossils is nicknamed Ardi
Describe Ardi
Ardi was about 1.2m tall and 50kg. Her leg bones show that she may have been able to walk upright. She had very log arms, though, and very long big toes that stuck out to the sides of her feet and would have allowed her to climb trees
When was Austraopithecus afarensis discovered?
In 1994. She lived 3.2 million years ago and was about 1.07m tall. She could probably walk upright, but although her toe bones were arranged in the same way as of modern humans, they were much more curved
What is the order of species evolved into each other?
Ardipthecus ramidus (Ardi) Australopithecus afarensis (Lucy) Homo hablis Homo erectus Homo sapiens (humans)
When was homo habilis discovered?
1960s, the fossils are 2.4-1.4 million years old, the animals were quite short with long arms but walked upright
When was homo erectus discovered?
In Asia in the late 19th century, and so many scientist thought that modern humans evolved in Asia. An almost complete 1.6 million year old skeleton was found by Richard Leakey in Kenya providing evidence that hipumans evolved in Africa, this species was tall (1.79m) and strongly bout
Go to page 77 and look At the
Diagram
Describe stone tools
Earliest evidence of human like animals using stone tools date back to about 3.3 million years ago. Scientists can work out the ages of different layers of rock. They then assume that a stone tool is about the same age as that layer of rock
The oldest stone tools are very simple, but would have helped with skinning an animal or cutting up meat. Tools found in more recipe get rocks are more sophisticated
Who discovered that organisms slowly evolve into others?
Charles Darwin and Alfred Russell Wallace
What is genetic variation?
When the characteristics of individuals vary to a difference in genes
What is environment change?
Conditions in an area change, eg the lack of recourse (such as food) causes more competition between organisms
What is natural selection?
By chance, the variations of some individuals make them survive better at coping with the change than others, and more likely to survive (also called survival of the fittest)
What is inheritance?
The survivors breed and pass on their variations to their offspring. So the next generation contains more individuals with the better adapted versions
What is evolution?
If the environmental conditions remain unchanged, natural selection occurs over and over again, and species evolve with the individuals having the better adapted versions
Until the 17th century, most Europeans did not think humans were animals, when did ideas start to change?
When Carl Linnaeus (1707-1778) published his system classification and suggested that humans were related to apes and monkeys. His biominal system, using two Latin words for naming species is still used today
How did elephants and woolly mammoths evolve from the same animal?
They share a common ancestor, scientists think that an area in which this ancestor lived started getting colder. Due to genetic variation, some animals by chance had harrier skin. They were more likely to survive the cold than less hairy animals, especially when food was scarce. More of these individuals survived and bred. Over time the animals became hairier and hairier, forming a new species
How were most rats resistant to warfarin?
Due to genetic variation they had always been some rates that were resistant. As the poison killed the non-resistant rats, the only ones left to breed were resistant.
How can some bacteria in people not be killed?
In a population of bacteria, some bacteria are more resistant than others and take longer to be killed. People who take an antibiotic to treat an infection often stop taking it early because they feel better. This leaves resistant bacteria still alive. They reproduce and spread, causing infections that cannot be treated with the antibiotic because all the bacteria are now resistant
When was resistant bacteria not present?
When antibiotics were first used
Go to page 79
And look at he diagram
In 1835 what did Charles Darwin do to make him wonder whether species could change form?
He visited the Galápagos Islands where he noticed differences in mocking birds on different islands
What gave Darwin the idea that organisms normally produce more offspring that could survive?
he read a essay by Thomas Malthus (1766-1834) which argued that, if people had too many children, there would not be enough food. Resulting struggle for survival, some children would die. Only those individuals best suited to the surroundings would survive and reproduce to pass on their characteristics. But he knew this was a controversial idea so he spent 20 years piecing together evidence
Why was Darwin more famous than wallace?
Because he wrote a book called the origin of species which was a bestseller and so the theory (about on,y those individual who was best suited to the environment would survive) was slowly being accepted
What a pentadactyl limb?
Limbs with 5 fingers
See page 81 and look at the diagram
All these animals have the same bones just in different shapes and sizes
What did Carl Linnaeus do in 1735 and describe it
He published his classification system, dividing organisms into groups based on what they looked like. His largest groups (kingdoms) where plants and animals, which divided into ever smaller and smaller groups. The characteristics of the organisms in a group got more and more similar as the groups go smaller and smaller. The last group contained one type of organism. Linnaeus used the last two groups (genus and species) to give each organism a binomial name
