Page 49 - Science Coursebook

3.3 Inheritance

Genes and environment
As we have seen, your genes are not the only reason for why you are you. Your

environment also has a big effect.
For example, a child might inherit the genes to grow tall from his parents. But if he
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does not get enough to eat while he is a small child, then he may not grow tall.
Fig 9.4D Rafaela, Tian-ning and Brad
Fig 9.4D Rafaela, Tian-ning and Brad
Some of your characteristics are to do with your behaviour, not what you look like.
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Eleanor Jones Eleanor Jones
Hola! Me
Uggh llamo Rafaela. Hi! My name's Brad.

The gorilla cannot speak words. She does not have genes to build a brain and vocal
chords that can produce speech. Rafaela and Brad do have these genes, so they can
both talk. But they speak in different ways because they have grown up in different

environments. Rafaela's family speak Spanish. Brad has grown up in an English-
speaking family.
Questions

3 The twins in the photograph have identical genes.

Describe three features of the twins in the photograph that are caused by
their genes.
4 Describe three of their features that are caused by their environment.

Summary
• Genes are passed on from parents to offspring.

• Genes provide a set of instructions that determine some of the
characteristics of an organism.
• Some characteristics are caused by an organism’s environment.

3 Variation and inheritance 47