Explain Darwin’s theory of evolution (including natural selection)
- Random mutations cause variations within a species
- A change in the environment such as a new predator will cause animals to compete for survival
- Some animals will have an advantageous allele allowing them to be better adapted and survive
- Surviving animals can reproduce and pass the gene on to the next generation
- Eventually the gene will accumulate in a population
Explain Lamarck’s theory of Acquired Characteristics
- He argued that if a characteristic was used a lot by an organism that it would become more developed
- These acquired characteristics would then be passed on to the next generation
What was Lamarck’s theory called?
The theory of Acquired Characteristics
Why was Lamarck’s theory rejected?
Experiments didn’t support his hypothesis, many characteristics acquired by animals aren’t inherited
Give three reasons Darwin’s theory wasn’t accepted.
- It went against religious beliefs at the time
- Darwin didn’t have any good explanation- genes weren’t discovered then
- There wasn’t enough evidence
Why do scientists come up with different theories for similar situations?
Scientists produce different hypotheses to explain the same observations because of many reasons e.g they have been influenced by other people or beliefs
What are hypotheses refused or supported by?
Data from investigations
How are living things classified into animals, plants and microorganisms?
By studying the similarities and differences between them:
- Animals: move around the place and can’t make their own food
- Plants: make their own food and are fixed
- Microorganisms: different cell structure to both plants and animals
What is an evolutionary relationship?
How living things are related
What is an ecological relationship?
How living things interact with each other
What does an evolutionary tree show?
Common ancestors and relationships between organisms.
The more recent the common ancestor…
…the more closely related the two species.
What do organisms in the same environment with similar characteristics suggest?
That they are in competition with each other
What do organisms in the same environment with different characteristics show?
Predator - prey relationships
What is the theory of evolution?
The theory that all species have evolved from life forms that first developed more than 3 billion years ago