Download Evolution - Brookville Local Schools

EVOLUTION
Biology
 James
Hutton and Charles Lyell studied
geological processes that shaped the
earth.
HUTTON AND LYELL
 The
earth is several billion years old and the
processes that changed earth in the past
are the same as the processes that operate
in the present. This is called
uniformitarianism.
HUTTON AND LYELL
 Jean-Baptiste
Lamarck was a French
naturalist who lived in the early 1800’s
 He
fought in the Pomeranian war,
studied medicine, botany, and later
became a professor of zoology.
LAMARCK
 Lamarck
proposed that all organisms have an
inborn urge to become more complex and
perfect.
 As
a result, organisms change and acquire
features that help them live more successfully
in their environment. He called these acquired
characteristics/traits.
LAMARCK
Proposed
 1.
Two Hypotheses
Organisms can change during their
lifetimes by selectively using or not using
various parts of their bodies
LAMARCK
Proposed
 2.
Two Hypothesis
Individuals can pass these acquired
traits on to their offspring, enabling
species to change over time
LAMARCK
 Thomas
Malthus reasoned that if the human
population grew unchecked, there wouldn’t
be enough living space and food for
everyone.
 Darwin
would later draw upon this idea and
discuss how it impacts organisms in the wild.
THOMAS MALTHUS
 Charles
Darwin developed a scientific
theory of biological evolution that
explains how modern organisms
evolved over long periods of time
through decent from common
ancestors.
CHARLES DARWIN
 Charles
1809.
Darwin was born in England in
 Despite
having a natural interest in the
environment, Darwin studied medicine.
 Eventually
he gave up medicine to pursue
his passion of studying different species
found in nature.
CHARLES DARWIN
 In
1831, Darwin partook in a five year voyage on the HMS
Beagle. The goal of the captain and crew was to map the
coastline of South America.
CHARLES DARWIN

Darwin, however, wanted to collect specimens of plants
and animals he encountered in the various geographical
regions.
CHARLES DARWIN

As Darwin collected specimens and recorded information
in his notebooks, he began noticing patterns.
CHARLES DARWIN
 Darwin
observed that:

Species vary globally.

Species vary locally.

Species vary over time.
CHARLES DARWIN
 Darwin
noticed that different, yet
ecologically similar, animal species
inhabited separate, but ecologically similar,
habitats around the globe.
SPECIES VARY GLOBALLY
 Rheas
in South America, Ostriches in Africa,
Emus in Australia

Why no rabbits in ideal Australian habitats?
Why no kangaroos in England?
SPECIES VARY GLOBALLY

Different, yet related, animal species often
occupied different habitats within a local
area.
 i.e.
– Two species of rheas living in South
America, but each in a different type of
grassland.
SPECIES VARY LOCALLY
 Tortoises
from Isabella Island have dome
shaped shells and short necks. On this
island, vegetation is abundant and close to
the ground.
SPECIES VARY LOCALLY
 Tortoises
from Hood Island have shells that
are curved and open around their long
necks and legs. This enables them to reach
the island’s spare, high vegetation.
SPECIES VARY LOCALLY

Darwin noticed that some
fossils of extinct animals were
similar to living species.
SPECIES VARY OVER TIME

After his voyage on the Beagle, Darwin began trying to
explain the changes he observed in nature.

Hutton, Lyell, Lamarck, and Malthus’ observations and
theories were considered.

He learned about a process known as artificial
selection from plant and animal breeders.
CHARLES DARWIN

In artificial selection, nature provides the
variations and humans select those they
find useful.
CHARLES DARWIN
 Years
later Darwin would publish his work in
a book he named Origin of the Species.

This book serves as a cornerstone of
evolutionary biology.
ORIGIN OF THE SPECIES

In his book, Darwin explains that his data
and observations in nature led him to the
following conclusions:

There is a struggle for existence

The influence of variation and adaptation

Survival of the fittest
ORIGIN OF THE SPECIES
 Natural
Selection is the process by which
organisms with variations most suited to
their local environment survive and leave
more offspring
NATURAL SELECTION
 Adaptation
– Any heritable characteristic
that increases an organisms ability to
survive and reproduce in its environment.
NATURAL SELECTION
 Fitness
– how well an organism can survive
in its environment.
NATURAL SELECTION
 When
does this occur?
 Natural
Selection occurs in any situation in which
more individuals are born than can survive (struggle
for existence), there is natural heritable variation
(variation and adaptation), and there is a variable
fitness among individuals (survival of the fittest).
NATURAL SELECTION
 Natural
selection does NOT make
organisms better or perfect – just good
enough to enable an organism to pass
its genes on to the next generation.
(too bad bruh.)
NATURAL SELECTION
 Just
as well adapted individuals in a
species survive and reproduce, well
adapted species survive over time.
 Living
species are descended, with
modification, from common ancestors. An
idea called descent with modification.
COMMON DESCENT