Transcript The Organization of Life

The Organization of Life
Everything is Connected
Ecosystem
• All of the organisms
living in an area
together with their
physical environment.
Components of an Ecosystem
• Abiotic—nonliving parts
of the ecosystem.
including air, water,
rocks, sand, light,
weather, and
temperature
• Biotic—living and once
living parts of an
ecosystem.
• Organism—individual living thing
• Species—group of organisms that are
closely related and can mate to
produce offspring.
• Population—all the members of the
same species that live in the same
place at the same time
• Community—a group of various
species that live in the saqqme place
and interact with each other
• Habitat--the place an organism lives
What is Evolution?
• In the biological sciences, evolution is
a scientific theory that explains the
emergence of new varieties of living
things in the past and in the present;
it is not a "theory of origins" about
how life began.
http://evolution.berkeley.edu/evolibrary/home.php
http://evolution.berkeley.edu/evolibrary/home.php
www.darwinday.org/englishL/life/beagle.html
www.darwinday.org/englishL/life/beagle.ht
Used by permission of Darwin Day
Celebration (at DarwinDay.org), 2006
I have called this principle, by which
each slight variation, if useful, is preserved,
by the term Natural Selection.
—Charles Darwin from "The Origin of Species"
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Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
Isn’t evolution only a theory?
A scientific theory is a framework that guides
research, not an idle speculation or a “hunch.”
These theories are systematic, well-tested
explanations that account for a broad range of
observations.
Biological evolution is a scientific theory that
explains the pattern and process of variation and
similarity among living things in terms of the
common ancestry of living organisms.
It is a widely accepted and applied theory because
it continues to guide useful research and answer
new questions even after 140 years
Three important concepts within
evolutionary biology:
• the definition of evolution (common
ancestry and descent with modification)
• the processes of evolutionary change
(for example, natural selection and genetic drift)
• The patterns of evolutionary
relationships (depicted as phylogenetic
trees).
Tree of Life
Tree of Life
phylogeny, the ascent of all species through time,
Root of the Tree
• The "archaea tree":
• The "eocyte tree":
EVIDENCE OF EVOLUTION
• STRUCTURAL ADAPTATIONS
– MIMICRY
– CAMOUFLAGE
http://evolution.berkeley.edu/evolibrary/home.php
http://science.howstuffworks.com/animal-camouflage2.htm
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What
Is
It?
 Describe this specimen. What do you observe?
 Is this a terrestrial or marine animal?
 What anatomical features support your
hypothesis?
 Is this a modern or ancient animal? If ancient,
what modern day animal does it resemble?
OTHER EVIDENCE OF EVOLUTION
• FOSSILS
• ANATOMY
– HOMOLOGOUS STRUCTURES
http://evolution.berkeley.edu/evolibrary/home.php
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
OTHER EVIDENCE OF EVOLUTION
• FOSSILS
• ANATOMY
– HOMOLOGOUS STRUCTURES
– ANALOGOUS STRUCTURES
http://evolution.berkeley.edu/evolibrary/home.php
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
OTHER EVIDENCE OF EVOLUTION
• FOSSILS
• ANATOMY
– HOMOLOGOUS STRUCTURES
– ANALOGOUS STRUCTURES
– VESTIGIAL STRUCTURE
– EMBRYOS
http://evolution.berkeley.edu/evolibrary/home.php
WHAT IS ANOTHER EXAMPLE
OF VESTIGIAL STRUCTURES?
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
OTHER EVIDENCE OF EVOLUTION
• FOSSILS
• ANATOMY
– HOMOLOGOUS STRUCTURES
– ANALOGOUS STRUCTURES
– VESTIGIAL STRUCTURE
– EMBRYOS
• BIOCHEMISTRY
– WHAT 2 THINGS?
http://evolution.berkeley.edu/evolibrary/home.php
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
WHAT IS SPECIATION?
• GEOGRAPHIC ISOLATION
• REPRODUCTIVE ISOLATION
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Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
ADAPTIVE RADIATION – AN EXAMPLE
OF DIVERGENT EVOLUTION
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Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
Evolution
•
•
•
•
Natural Selection
Adaptation
Artificial Selection
Evolution of
Resistance
Natural Selection
• Over many generations
natural selection causes
the characteristics of
populations to change.
• Darwin and Fossils
--remains of extinct species
from which modern
species evolved.
NATURAL SELECTION
• Organisms produce more offspring than
can survive
• Environment is Hostile and contains
limited resources
• Some inherited traits provide organisms
with an advantage
• Each generation contains proportionately
more organisms with advantageous traits
Traits were the Key
• Organism produce more offspring than
can survive.
• Result: periods of more diversity if more
food
Environment is Hostile
• Environment contains
things and situations
that can kill
organisms, and the
resources needed to
live, such as food and
water, are limited.
• Name an example.
Survival of the Fittest
What does this
mean to you?
• The fittest is one that
survives to pass its genes
on, is the one most
adapted to its current or
changing environment. It
doesn’t necessarily mean
it has to fight to survive.
Organisms Differ in Traits
• Resistance to
disease
• Coloration
• Size
• And so on….
Inherited Traits are an Advantage
• Coping with
Environmental
Challenges
• “naturally selected
for”
• Survive longer and
produce more
offspring
change to distribution of traits
• directional selection (favors phenotypes at
one extreme)
• stabilizing selection (favors intermediate
phenotypes)
• disruptive selection (favors phenotypes at
both extremes)
Each Generation contains
proportionately more organisms
• Trait changes show
up in greater
proportion of offspring
than previous
generations.
When is it a new Species?
• When a group of
organisms are capable
of interbreeding and
producing fertile
offspring based on
similarity of DNA.
How does the genetic
pool change?
ALL IMAGES: http://evolution.berkeley.edu/evolibrary/home.php
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
Adaptations
• Inherited trait that
increases an
organism’s chance of
survival and
reproduction in a
certain environment.
Animals of the Prairie
Darwin’s Finches Activity
Form Four groups for four different species
of finch’s bills:
• A. Thin
• B. Medium
• C. Small and powerful
• D. Large and powerful
Draw Cards to simulate food types
Adapted (civilized) Crops
• Corn was once a
grass (teosinte)
• Cotton
• Tomatoes
• Chili peppers
• Tobacco
• Pineapple
• Squash
• avocadoes
Coevolution
• Organisms that adapt
to other organisms as
well as to their
physical environment.
• Bird developed a
curved thin beak to
reach nectar; flower
developed to ensure
pollen would get onto
head as it sips nectar
Artificial Selection
• Selective breeding of
organisms by humans
for specific
characteristics.
Resistance Evolution
• Ability of one or more organisms to tolerate a
particular chemical design to kill it.
• A. Billbug
B. Sugar Cane Beetle
• 1. Insect pests are sprayed with an
insecticide. Only a few resistant ones
survive.
• 2. The survivors pass on the trait for
resistance to offspring.
• 3. When the same insecticide is used
again, more insects survive.
Diversity of Living Things
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•
•
•
•
Bacteria
Fungi
Protists
Plants
Animals
Bacteria
• Archaebacteria—live
in harsh environments
like hot springs
• Eubacteria—very
common throughout
terrestrial and aquatic
environments.
Fungus
• All fungi absorb their food
(after breaking it down
chemically) from their
surroundings.
• Some fungi causes
diseases (Athlete’s foot)
• Other fungi add flavor to
food (blue cheese or
yeast to produce gas to
make bread rise)
Protists
• either they are
unicellular, or they are
multicellular without
specialized tissues.
• This simple cellular
organization
distinguishes the
protists from other
eukaryotes, such as
fungi, animals and
plants.
Plants
Gymnosperms “naked sperm”—evergreens
woody plants whose sees are not
enclosed in fruits.
Angiosperms “vessel seed”—most plants
flowering plants that produce seeds in
fruit
Angiosperm Challenge
Get into groups of four
(4) people
At the signal, you have
three minutes to write
down everything that
is a product of an
angiosperm.
Animals
Invertebrates-lack backbones
Vertebrates-amphibians, reptiles, birds, mammals
Insects
• More insects exist on Earth than any other
animal
Successful because….
• Have waterproof external skeleton
• Small size means less food needed
• Reproduce quickly
• Move quickly