The members of this family tree are related and so they share
certain similar characteristics. So why dont all family members
look exactly alike?
Slide 4
People are similar, but not identical, to their parents or each
other. The differences in a species are called variation. Variation
can come about for two reasons. What are they?
Slide 5
People inherit characteristics from both of their parents These
are called inherited variations. Other characteristics are affected
a person surroundings. These are called environmental
variations.
Slide 6
Slide 7
Can you think of other environmental and inherited variations?
EnvironmentalInherited
Slide 8
How does a builder know what kind of building to build? How
does grandma know how to work the DVD player?
Slide 9
How do our eyes know to be blue? How do our heart cells know to
keep beating?
Slide 10
Genetic material (DNA) contains the instructions used by living
things. Genetic material is found in the nucleus of cells.
Slide 11
If we look closer into the nucleus we can actually see the
genetic material as chromosomes. Although chromosomes appear short
and fat, they are actually very long strands that are tightly
coiled.
Slide 12
Slide 13
When we look closer still, we find that chromosomes are complex
structures made of molecules of deoxyribonucleic acid (DNA ).
Slide 14
DNA contains all the information required to build a living
organism. Each chromosome is made up of two long DNA molecules. The
two molecules are twisted around each other forming a double
helix.
Slide 15
Within the long strands of DNA we find genes. A gene is a
section of the DNA that contains the code for a specific inherited
trait. Every person is unique because they have different
combinations of genes.
Slide 16
An allele is an alternative form of a gene. Person #1 may have
the Brown allele of the eye colour gene. Person #2 may have the
Blue allele of the eye colour gene.
Slide 17
Karls DNA Hollys DNA Eye Colour Gene
Slide 18
Slide 19
Slide 20
TraitMEMumDad Class Total Tongue Roller Non Tongue Roller
Attached Ear Lobe Free Ear Lobe Cleft Chin Flat Chin Hitchhikers
Thumb Straight Thumb Widows Peak Straight Hairline Right Handed
Left Handed
