SB4 Flashcards
Define evolution
Evolution is the slow and continuous change of organisms from one generation to the next.
What is a binomial species name?
- Genus/generic name
- Species name
Homo sapiens
Explain how evidence from fossils supports current ideas about human evolution.
- The features from the fossils are a mixture of those found in humans and apes.
- Most fossils are found in rock.
- Generally the deeper the rock the older the fossil.
- By arranging fossils in chronological order gradual changes can be seen. This provides evidence because it shows how species have changed and developed.
How are stone tools dated from their environment?
By looking at the age of the sediment layers its found in
The deeper it is the older it tends to be.
How have stone tools developed over time?
- Becoming more efficient and better suited for the job
- Simple = more complex
- Pebbles = rocks = flint and wood
Describe the fossil evidence for human like species…
- 4.4 million years ago = Ardi. Structure of feet suggest she climbed trees. Long arms, short legs. Brain size similar to chimpanzees. Structure of legs suggests she walked upright.
- 3.2 million years ago = Lucy. Arched feet-more adapted to walking. Arms and legs were a mixture. Brain slightly larger. Walked upright mor efficiently.
- 1.6 million years ago = Leakey. More human like. Short arms, long legs. Brain size similar to humans. Better adapted to walking upright.
What is the cause of genetic variation?
It’s due to the mutation of genes.
How do adaptations allow organisms to survive?
- Organisms are adapted to survive in different conditions. The better suited they’re for an environment the more chance they have of surviving.
- For example = polar bears are well adapted for the artic.
Thick fur and fat
White fur for camouflage
How does natural selection allow some members of a species to survive better than others when conditions change?
Individuals in a species show a wide range of variation and this variation is because of differences in their genes.
Individuals with characteristics most suited to their environment are more likely to survive and reproduce. The genes that allow these individuals to be successful are passed to their offspring.
How can natural selection lead to the evolution of a new species?
Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than others in a population and pass on these characteristics to their offspring.
The offspring will inherit these characteristics and the cycle will happen all over again.
Explain how the development of resistance in organisms supports Darwin’s theory
It shows how an organism has had to adapt/evolve to be better suited to its surroundings.
What are the names of the scientists who first developed the theory of evolution by natural selection?
Charles Darwin
Alfred Russel wallace
Describe some of the evidence Darwin and Wallace used to support their ideas
Bacteria = would become less affected by particular antibiotics (resistant).
Shows bacteria is better adapted to an environment.
What is the impact of the idea of evolution on modern biology?
It has made scientists look in more depth at how creatures have developed/adapted to the changing environment.
Understand many areas of biology.
All life changes by evolution.
All descended from a common ancestor.
What is meant by the pentadactyl limb?
Where is it found?
It’s a limb with 5 digits.
It’s found in mammals, reptiles e.t.c
For example a human hand and a bats wing.
The limb has a similar structure in these different species.
The similarity suggests and gives evidence towards evolution in species with a pentadactyl limb have all evolved from a common ancestor.
Explain how changes to the pentadactyl limb provide evidence for evolution by natural selection.
It shows how individuals have had to adapt to different environments.
For example bats and birds pentadactyl limb have changed so they can fly whereas humans have evolved so they can hold things.
