The Organization of Life Everything is Connected

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.

I have called this principle, by whicheach slight variation, if useful, is preserved,

by the term Natural Selection.

  —Charles Darwin from "The Origin of Species"Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

http://evolution.berkeley.edu/evolibrary/home.php

www.darwinday.org/englishL/life/beagle.htUsed by permission of Darwin Day Celebration (at DarwinDay.org), 2006

www.darwinday.org/englishL/life/beagle.html

http://evolution.berkeley.edu/evolibrary/home.php

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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.phphttp://science.howstuffworks.com/animal-camouflage2.htm

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?

What

Is

It?

OTHER EVIDENCE OF EVOLUTION

• FOSSILS• ANATOMY

– HOMOLOGOUS STRUCTURES

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

OTHER EVIDENCE OF EVOLUTION

• FOSSILS• ANATOMY

– HOMOLOGOUS STRUCTURES– ANALOGOUS STRUCTURES

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

OTHER EVIDENCE OF EVOLUTION

• FOSSILS• ANATOMY

– HOMOLOGOUS STRUCTURES– ANALOGOUS STRUCTURES– VESTIGIAL STRUCTURE– EMBRYOS

WHAT IS ANOTHER EXAMPLE OF VESTIGIAL STRUCTURES?

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

OTHER EVIDENCE OF EVOLUTION

• FOSSILS• ANATOMY

– HOMOLOGOUS STRUCTURES– ANALOGOUS STRUCTURES– VESTIGIAL STRUCTURE– EMBRYOS

• BIOCHEMISTRY– WHAT 2 THINGS?

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

WHAT IS SPECIATION?• GEOGRAPHIC ISOLATIONGEOGRAPHIC ISOLATION• REPRODUCTIVE ISOLATIONREPRODUCTIVE ISOLATION

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

ADAPTIVE RADIATION – AN EXAMPLE OF DIVERGENT EVOLUTION

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

http://evolution.berkeley.edu/evolibrary/home.php

http://www.vanderbilt.edu/AnS/english/Clayton/Galapago_finches.gif

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.

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

ALL IMAGES: http://evolution.berkeley.edu/evolibrary/home.php

How does the genetic pool change?

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

• 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