Download Why Study Biology? Biology helps you understand your body

5/18/2012
Why Study Biology?
1.2 How Do Biologists Study Life?
 Biology helps you
understand your body.
 Biology helps you
become an informed
citizen.
 Biology can open career
opportunities.
 Biology can enrich your
appreciation of the world.
 It helps you understand
how the world works!!
 The scientific method is the basis for
scientific inquiry.
 Life can be studied at different levels of
organization.
 Science is a human endeavor.
 Scientific theories have been thoroughly
tested.
Copyright © 2009 Pearson Education Inc.
Copyright © 2009 Pearson Education Inc.
How Do Biologists Study Life?
How Do Biologists Study Life?
 The scientific method
 Life can be studied at different levels of
organization.
•
•
•
•
•
•
•
Observation
Question
Hypothesis (proposed explanation)
Prediction
Experiment or observation
Conclusion
Communication to others
cell
nerve cell
tissue
nervous tissue
organ
brain
organism
pronghorn antelope
population
herd of pronghorn antelope
community
snakes, antelope, hawks, bushes, grass
Fig. 1-5
Copyright © 2009 Pearson Education Inc.
Copyright © 2009 Pearson Education Inc.
What Is Life?
What Is Life?
 What characteristics do all living things have?
• Living things are organized.
 Characteristics of living things
• Living things are complex
Fig. 1-8
Copyright © 2009 Pearson Education Inc.
Fig. 1-8
Copyright © 2009 Pearson Education Inc.
1
5/18/2012
What Is Life?
What Is Life?
 Characteristics of living things
• Living things are organized and complex.
 Characteristics of living things
• Living things grow and reproduce.
Fig. 1-8
Copyright © 2009 Pearson Education Inc.
Fig. 1-9
Copyright © 2009 Pearson Education Inc.
What Is Life?
What Is Life?
 Characteristics of living things
 Characteristics of living things
• Living things respond to stimuli – such as?
• Light
• Sound
• Chemicals
• Hunger
• Pain
• Touch
• Heat
• Cold
• Motion
• Gravity
• Living things acquire and use energy.
Fig. 1-10
Copyright © 2009 Pearson Education Inc.
Copyright © 2009 Pearson Education Inc.
What Is Life?
Why Is Life So Diverse?
 Characteristics of living things
 DNA: The universal molecule of life
• DNA is found in all organisms, from bacteria to
whales.
• DNA is passed from generation to generation during
periods of reproduction.
• Organism diversity results from small changes in
DNA accumulating over billions of years of
evolution.
• Its universal presence suggests that all organisms
have descended from a common ancestor having
the same molecule.
• Living things use DNA to store information.
Fig. 1-11
Copyright © 2009 Pearson Education Inc.
Copyright © 2009 Pearson Education Inc.
2
5/18/2012
Why Is Life So Diverse?
Why Is Life So Diverse?
 What does Biodiversity mean?
 Life’s unity and diversity is a result of evolution.
• Life changes over long periods of time.
• Groups of organisms genetically change from
generation to generation.
• Genetic changes that occur in populations of
organisms over time is evolution.
 Life’s unity and diversity is a result of evolution
• Life’s unity arises from the fact that diverse
descendents arise from single ancestors.
• The unifying principle of biology is that all of
life’s features in today’s organisms arose
through evolution.
Copyright © 2009 Pearson Education Inc.
Copyright © 2009 Pearson Education Inc.
Why Is Life So Diverse?
Why Is Life So Diverse?
 Natural selection is the basis of evolution
• Characteristics of individuals in a group vary.
• Some characteristics help individuals survive
and reproduce.
• Those that reproduce pass on these traits to
future generations.
• The favored traits are accumulated in
populations over time, changing the individuals
within the group.
• Example: Big teeth in beavers favor survival
and are passed on to future generations.
 Biodiversity is threatened by human activities.
• Biodiversity is the wealth of species in the world
and the interrelationships that sustain them.
• Human expansion in the world has severely
reduced habitats for these interrelationships to
flourish.
• Extinction of many organisms have followed
from the growth of human populations on all the
world’s continents.
• Pollution and chemical wastes kill aquatic
organisms.
Copyright © 2009 Pearson Education Inc.
Copyright © 2009 Pearson Education Inc.
Is there value in diversity? What good is it?





Food
Medicine
Art
Photography
Money
(harvest/tourism/equipment)
 Serenity
 Religion
 Natural balance
Fig. E1- 4
Copyright © 2009 Pearson Education Inc.
3