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30 Dec 2025

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2 pages

Evidence for Evolution: Biology Explained

Liza Saiyad

@liza_saiyad

Ever wonder how we know that dinosaurs existed millions of... Show more

Charles Darwin came up with the
theory that humans evolved
from apes. The organisms that
are most adapted will grow
and pass their genes on.

Darwin's Theory and Fossil Evidence

Charles Darwin developed the revolutionary idea that humans evolved from apes, introducing the concept that the most adapted organisms survive and pass their genes to the next generation. This process explains how species change over millions of years.

The main evidence for evolution comes from fossils - the preserved remains of organisms that lived millions of years ago. These aren't just dinosaur bones you see in museums; fossils include shells, hair, microbes, and even ancient poop!

The fossilisation process is quite remarkable. When an animal dies, its flesh rots away, leaving the skeleton to be buried in sand, soil, or clay. Over millions of years, the remains become mineralised and turn into rock. Eventually, erosion and rock movement bring these fossils to the surface where scientists can discover them.

Quick Tip: Fossils can also be preserved in ice (like woolly mammoths) or amber, giving us incredibly detailed snapshots of ancient life!

The Incomplete Fossil Record and Extinction

The fossil record has significant gaps, especially for early life forms. Most ancient organisms had soft bodies that decomposed completely, leaving little trace behind. Additionally, geological activity like earthquakes, volcanoes, and tectonic plate movement can destroy potential fossils before we ever find them.

Extinction means the complete disappearance of an entire species - think dodo birds, sabre-tooth tigers, or the massive megalodon shark. Once a species goes extinct, it's gone forever.

Several factors cause extinction. New predators might appear, or species may fail to adapt to changing environments. New diseases can wipe out populations, and more successful competitors might outcompete them for resources.

Sometimes mass extinction events occur - catastrophic disasters that eliminate multiple species simultaneously. These dramatic events have shaped life on Earth throughout history.

Remember: Extinction is a natural part of evolution, but human activities have dramatically increased the rate at which species disappear today.

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Biology

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199

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30 Dec 2025

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2 pages

Evidence for Evolution: Biology Explained

Liza Saiyad

@liza_saiyad

Ever wonder how we know that dinosaurs existed millions of years ago, or why certain animals like the dodo bird no longer exist? Darwin's theory of evolution and fossil evidence help us understand how life on Earth has changed over... Show more

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Darwin's Theory and Fossil Evidence

Quick Tip: Fossils can also be preserved in ice (like woolly mammoths) or amber, giving us incredibly detailed snapshots of ancient life!

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The Incomplete Fossil Record and Extinction

Extinction means the complete disappearance of an entire species - think dodo birds, sabre-tooth tigers, or the massive megalodon shark. Once a species goes extinct, it's gone forever.

Sometimes mass extinction events occur - catastrophic disasters that eliminate multiple species simultaneously. These dramatic events have shaped life on Earth throughout history.

Remember: Extinction is a natural part of evolution, but human activities have dramatically increased the rate at which species disappear today.