Inheritance, Variation and Evolution Variation

variation is due to environmental or genetic causes.
To explain how

variation arises.

To voyage on the HMS Beagle and describe the variation that you find.

Learning Objective

Success Criteria

Targeting Assessment Objectives AO1, AO2 and AO3.

granted under creative commons licence – attribution
Jane Goodall
Charles Darwin
David Attenborough
Marie

Curie

Albert Einstein

Rosalind Franklin

8 years old and he was raised by his 3

older sisters.

Darwin was condemned by his headmaster for studying chemistry.

He studied medicine at Edinburgh University.

He spent a lot of his time at university collecting sea slugs on the shoreline.

He hated studying anatomy.

He was educated in theology at Christ Church, Cambridge University.

He set sale for a voyage on the HMS Beagle in December 1831, at the age of 22.

All true!

to study animals and humans in many different environments.

He collected

huge fossils of extinct mammals and once returned with a 71cm skull attached to his horse. It made him think about what made these animals die out.

He made lots of observations of the land and gathered evidence that supported geologist Lyell’s uniformitarian theory that the land can rise and fall.

He collected 5436 skins, bones and carcasses of animals, with 1750 pages of notes on the species he saw and a 770 page diary.

HMS Beagle, ready to help Darwin to collect information about

the species you encounter.

In each place you need to record the features of the environment around you.

on the open sea. Darwin distracts himself from terrible sea

sickness by talking through all of your notes.

Even animals that are of the same species, like the flatworms and humans, seem to have differences between them. What sort of differences did we find?

Can you explain what the word variation means?

I wonder what causes this variation?

before Mendel came up with the idea of inheritance of

genes, and another 65 years after that before they were linked with Darwin’s ideas.

We now know that variation could be due to:
the genes that have been inherited (genetic variation);
the conditions in which they have developed (environmental causes);
a combination of genes and the environment.

Pause for Thought
What do you think caused the variations you observed on your voyage?

you’ve collected today is continuous?
Types of Variation
Some data is continuous,

it can be measured on a scale.

Some data is discrete, it fits into categories.

the new phenotype is suited to the environment, it can

lead to a change in the species.

Most have no effect on the phenotype.

Very rarely one will change the phenotype.

a population.
Fits into categories.
Fits on a scale.
A change in the

DNA. Rarely it causes a change in the phenotype.

genetic

both

genetic

environmental

genetic

genetic

genetic

environmental

discrete

discrete

continuous

continuous

discrete

discrete

continuous

discrete

on?

These foals may not grow up to be

the same height, give two reasons why.

genes

They may have inherited different genes from their parents (genetic cause). They may not have the same supply of food (environmental cause).