1 & 2 - Concept and Manifestations of Life

Biology 1 Topics 1 and 2- Concept and

Manifestations of Life

1

Topic 1

B. Theories on the Origin of Life

A. Manifestations and Characteristics of Life

This handout is for lecture use only and not for commercial reproduction and

distribution.

Biology is the study of life

What is LIFE?

The Concept of Life

• Most contemporary biologists define life as a

particular set of processes that result from

the organization of matter

Characteristics of All Forms of Life

Organization and

OrderReproduction

Growth and development

Energy

processing

Response to the

environment HomeostasisEvolutionary adaptation

All forms of life share common properties/characteristics

1. Organization and Order—the highly ordered structurethat typifies life

2. Energy processing—the use of chemical energy to power an organism’s activities and chemical reactions

3. Metabolism/Homeostasis—an ability to control an organism’s internal environment

4. Response to the environment/Movement—an ability to respond to environmental stimuli



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5. Reproduction—the ability of organisms to reproduce their own kind

6. Growth and development—consistent growth and development controlled by inherited DNA

7. Evolutionary adaptation— variation, change and adaptation

Manifestations and Characteristics of Life

1. Life is highly organized (ORGANIZATION).

Atom Smallest unit of an element composed of electrons, protons and neutrons

Molecule Union of two or more atoms of the same or different element

Specialized structure composed of complex molecules within a living cell

Organelle

Cell Structural and functional unit of living things; consists of organelles

Tissue Group of cells with common structure and function

Organ Group of tissues functioning together for a specific task

Organ system Composed of several organs functioning together

Organism Individual containing organ systems

Population Organisms of the same species in a particular area

Community Interacting populations in a particular area

Ecosystem Community plus the physical environment

Biosphere Regions of the Earth’s crust, water and atmosphere inhabited by living things

Organism’s

Organization and

Order

Biosphere

Madagascar

Ecosystem:

Forest in

Madagascar

Community:

All organisms in

the forest

Population:

Group of ring-tailed

lemurs

Organism:

Ring-tailed lemur

Organ system:

Nervous system

Organ:

Brain

Tissue:

Nervous tissue

Nerve

Spinal cord

Brain

Organelle:

Nucleus

Cell:

Nerve cellNucleus Atom

Molecule:

DNA

• characteristics

of life emerge

from an

organism’s

organization


2. Life requires a constant input of energy and raw

materials (METABOLISM).


3. Life has strong internal control (HOMEOSTASIS)



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4. Life reacts to the environment (IRRITABILITY &

MOVEMENT).

Irritability is a state of extreme sensitivity to stimulation of any kind.


5. Life reproduces itself (REPRODUCTION).


6. Life grows (GROWTH & DEVELOPMENT).


7. Life varies and evolves (ADAPTATION &

EVOLUTION).


7. Life varies and evolves (ADAPTATION &

EVOLUTION).

African wild

dogCoyote Fox Wolf Jackal

Thousands to

millions of years

of natural selection

Ancestral canine

How did life BEGIN?

http://www.ojibway.ca/harmonia2.jpg



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Theories on the Origin of Life

1. ABIOGENESIS / SPONTANEOUS GENERATION

•Life was created spontaneously from lifeless or

inorganic matter

www.fotosearch.com/comp/ITS/ITS223/itf139053.jpg

• Louis Pasteur’s 1862 experiment disproves abiogenesis

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings


2. BIOGENESIS

•Life comes from pre-existing life

http://www.artoftheprint.com/jpegimages/rausch_anton_mother_and_child.jpg


3. SPECIAL CREATION

•Life was created by supernatural or divine forces

www.bibledirectories.com/.../What-is-it.html


4. INTERPLANETARY / COSMOZOIC THEORY

•Life originated on a distant planet

•Also known as PANSPERMIA

Panspermia Theory suggests that life seeds came from outer space and planets

exchanged life.


5. BIOGEOCHEMICAL THEORY

•Life evolved from inorganic matter

•Chemical and physical processes in Earth’s primordial

environment eventually produced simple cells.

http://www.rogerwendell.com/images/evolution/dmns_recipe_for_life_09-02-2006.jpg

http://www.bibledirectories.com/Intelligent-Design-Creationism-Evolution/What-is-it.html







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• Laboratory simulations cannot prove that these kinds of chemical processes actually created life on the primitive Earth.

• They describe steps that could have happened.

• The origin of life is still subject to much speculation and alternative views.

Debates about the origin of life abounds


Time Line of

Life on Earth


• Alternatively, we can view the time line with a clock analogy.

Documents

1 & 2 - Concept and Manifestations of Life