NSWTR 2024 HR - Flipbook - Page 52
YEAR 9-10 SECTION
BIOLOGY+SPECIES SURVIVAL INTRODUCTION
THE LANGUAGE
OF LIFE
Ye
ar 9-10
SHUTTERSTOCK
The more we discover about DNA, the better we
understand not just how far life has come, but
also how we can help it survive.
round 3.5 billion years ago, life on Earth began with singlecelled organisms. Today, scientists estimate there are over 8.7
million di昀昀erent living things in existence, including everything
from humans to plants, bacteria and other animals.
This incredible diversity is all thanks to evolution. But to
understand evolution, we 昀椀rst need to understand genetics.
Deoxyribonucleic acid (DNA) is a very long molecule that’s made
up of two strands twisted around each other. Each strand consists
of di昀昀erent sections called genes. Every individual within a single
species shares similar genes, but none are exactly identical – not even
in ‘identical’ twins!
Genes are what make living things unique. They determine things
like how tall a tree will grow, when a 昀氀ower will bloom and what
colour eyes we have. These genetic variations can occur for a few
di昀昀erent reasons, but mutations – changes in the sequence of genes
– are the most common.
Often, genetic mutations can lead to disease or cancer, but
occasionally, they cause a physical or behavioural change that helps
an organism survive. The next time you see an echidna, take a closer
look at its hind legs. They point backwards! This mutation helps
echidnas push dirt out of the way when they’re burrowing. When a
mutation helps, rather than hinders, it becomes an adaptation – and
it’s passed down to future generations. Eventually, a population of
organisms might develop a set of genes, which we call a genome, that
is so di昀昀erent to that of its closest relatives that we consider it to be
an entirely new species.
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SPECIES SURVIVAL – MORE THAN JUST SUSTAINABILITY
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