Transcript Intro to Darwin and Biodiversity

EVOLUTION
An Introduction
Evolution
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Evolution = a change over time
In biology, it is the series of facts,
observations, and hypotheses about the
history of life.
Evolution is the unifying principle of
biology. It explains how living things are
related, from the smallest cells to the
largest animals.
It Began With Charles Darwin
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In 1831, the HMS Beagle set sail from Britain
on a five year cruise
Charles Darwin was the ship’s naturalist
While on the voyage, Darwin studied the
plants and animals he saw, collecting
samples
The Voyage of the HMS Beagle
Living Diversity
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Darwin was overwhelmed by the living
diversity he saw (variety of plants of
animals)
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Scientists estimate that there are as many as
31 million different species on Earth – only
1.75 million have been identified
Living Diversity
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Today, we call it biodiversity
Biodiversity is defined as the variety of
living organisms, the genetic information
they contain, and the biological
communities in which they live
There are three levels of biodiversity:
ecosystem diversity, species diversity,
and genetic diversity
What is an ecosystem?
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Ecosystems are communities of organisms
and their environments.
Ecosystem diversity includes the variety of
habitats, living communities, and ecological
processes in the living world.
There are so many ecosystems because
there is so much life.
What is a species?
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A species is a group of similar looking
organisms that can successfully reproduce
fertile offspring.
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Each species has its own gene pool, which
is the set of genes that are shared by all
members of the species.
Species Diversity
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Species diversity is the variety of species
that exist on Earth.
In an ecosystem, each species (plants,
animals, unicellular organisms) are important
for the health and survival of the whole
ecosystem.
The more species that live in an
ecosystem, the better for that ecosystem.
Genetic Diversity
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In general - refers to the sum total of all the
different forms of genetic information carried
by all organisms living on Earth today
Within a species – refers to the total variety
of all alleles in the gene pool
Individuals within the same species may
share the same genes, but they can still look
and act very different.