Unit 1: Chapter 7 - Evolution Flashcards
Accepting Darwins ideas
Why did people object?
- Natural selection challenged belief of God. The religious view was accepted by most people in Early Victorian England.
- No scientific evidence (genes) to support his ideas.
- There was no mehanism to explain inheritance - by genes and genetics.
Natural Selection
Survival of the fittest
Only the offspring with the genes best suited to their habitat managed to stay alive and breed successfully.
Passing genes to the offspring is called EVOLUTION.
The part played by mutation
New forms of genes result from changes in existing genes. These changes are known as mutations.
Mutations occur quite naturally through mistakesmade in copying DNA when the cells divide.
Some mutations are harmful whereas occasionally they can be a good effect.
The mutant gene will gradually become more common in the population. It will cause the species to evolve.
Classification and Evolution
The system we use for classifying living things is known as the natural classification system.
The biggest groups all the kingdoms and the best known of the animal kingdom and the plant kingdom. Kim kingdoms contain lots of organisms with many differences but a few important similarities.
For example, all animals move their whole bodies about at least part of their life cycle and their cells do not have cell walls.
The smallest group is a species. Members of the same species are very similar. Any differences are small variations of the same feature.
Classification and Evoloutionary Relationships
Scientists have used evolutionary trees to sure the evolutionary links between different organisms.
Scientists are using DNA evidence to decide what species an animal belongs to. This allows them to work on the evolutionary relationships between organisms.
Evolutionary and Ecological relationships
Classifying organisms helps us to understand how they evolved. We call this ecological relationships and it is another way of modelling relationships between organisms.
Theories of Evolution
Theories of evolution tells us that all living things alive today have first devloped from simple life forms.
JEAN-BAPTISTE LAMARCK
Inheritance from acquired characteristics.
He believed that the way an organism behaves affects the features of their bodies.
If people kept using a feature, it woulf grow and develop. This would then be passed down to offspring.
This was not accepted because:
- People didn’t like the idea of being descended from worms.
CHARLES DARWIN
His theory was natural selection. He simply observed inherited characteristics that were passed on.
