Natual Selection And Genetic Modification Flashcards
What is evolution?
The gradual change in a species characteristics over time
What is Darwin’s theory of natural selection also referred to as?
Survival of the fittest
What is natural selection?
The natural process where the best-adapted individuals survive longer, have more offspring so spread their characteristics
What species was Ardi?
Ardipithecus ramidus
What species was Lucy?
Australopithacus afarensis
What was significant about Mary and Louis Leaky’s discoveries from 1.6 m.y.a?
The skeleton looks much more like a modern human than either Ardi or Lucy. This skeleton suggests that humans may have evolved.
Order these species in how long ago they lived (oldest to current)
- Homo sapiens
- Homo habilis
- Ardipithecus ramidus
- Australopithecus afarensis
- Homo erectus
- Adripithecus ramidus
- Australopithecus afarensis
- Homo habilis
- Homo erectus
- Homo sapiens
How long ago did Adripithecus ramidus live?
4.4 m.y.a
How long ago did Australopithecus afarensis live?
3.2 m.y.a
How long ago did Homo habilis live?
1.6 m.y.a
How long ago did Homo erectus live?
0.8 m.y.a
How long ago did Homo neanderthalensis live?
0.2 m.y.a
What was the first species of human to make stone tools?
Homo habilis
What are fossils?
The imprints or remains of organisms which were alive thousands or millions of years ago
What are the different ways fossils can be formed?
- From the organism’s remains
- From a footprint or imprint (trace fossils)
How are fossils formed?
- Organism dies and is covered in sediment
- Over thousands of years more sediment is deposited on top
- The weight and the pressure causes the deposits to form sedimentary rock
- Minerals replace air spaces in the organism and the parts of the organism left will turn to stone
- Geological activity like earthquakes or mountains being formed will cause the fossils to rise up and become exposed
What evidence is there that humans evolved based on fossils?
Skull volume gets larger as human like species evolved (Ardi had skull volume of 350 cm2 and Homo sapiens have an approximate skull volume of 1450 cm2) and the theory of evolution states that simple life forms will evolve into more complex ones
Why do we not have fossils for every species that lived on Earth?
- Early organisms had soft bodies, which would have decayed
- Many fossils have been destroyed by geologic activity such as volcanoes
- Many fossils still have not been discovered