Lamarck believed that structures of individuals in a population become better or less adapted to the environment depending on the frequency of their use and that these adaptations could be inherited from generation to generation.
He suggested that change was driven by living things themselves as they strove to perfect their way of life.
More complex organisms developed from less complex organisms.
He supported the idea of common descent and linked diversity with adaption to the environment.
He supported the idea of the inheritance of acquired characteristics.
A mutation is a mistake/alteration due to a change on the composition of DNA. / OR Sudden change in the structure of a gene.
By accident during meiosis.
Some chemicals/mutagens/high energy radiation.
It is the ability to bring the thumb and the fingers together to form a pincer-like grip.
It has allowed man to pick up small objects and use small tools and weapons.
This in turn has allowed man to develop new technologies, tools and weapons.
The gorilla uses its hands for walking as well as holding and gripping things.
Humans only use their hands for holding and gripping.
The geographic barrier (e.g. a river) separates two groups of the same species.
The environmental conditions either side of the barrier differ, so each group undergoes natural selection independently.
Those well adapted will survive, reproduce and pass their genes to their offspring.
Those badly adapted will die out and not reproduce
In time, the two groups may become so different, that they are not able to interbreed if they were to meet.
They will have become different species.
The chimpanzee.
The foramen magnum is further back on the skull of the chimpanzee.
Taung child, Mrs Ples, Little Foot, Karabo child. (Any2)
Long roots
Natural selection
The cacti within a particular population show considerable variation.
When the environment becomes very dry, only the cacti with the favourable variation of having long roots is able to get enough water to survive.
The cacti with the short roots cannot get enough water and die.
Only the cacti with long roots survive and reproduce. So that eventually, the only plants that are left, are the ones with long roots.
Genetic information is swopped between chromosomes during crossing over which takes place in prophase I of meiosis.
The chromosomes arrange themselves in a random manner at the equator of the cell during metaphase I and metaphase II of meiosis. This random assortment of chromosomes increases genetic variation.
Mutations are changes to the base sequence of DNA, which change the genes and thus change the expression of the gene in the phenotype.
Each gamete that is formed is genetically different from all the other gametes.
Which sperm cell with fuse with the egg cell is entirely random, and one cannot always predict which mates an individual may choose out of the group.
