Biology: The Study of Life

Biology I – An Introduction

What is Biology?

• The scientific study of living things

• from the Greek words bios = life

&

-ology = the study of

Why Study Biology?

Understand the natural world

Learn to protect the environment

Develop skills for learning in your future lives

Reject Myths that Explain Biological Processes

• for example…

• Disease is caused by evil spirits

• Your blood determines your heredity

• Your heart carries your emotions

How Does Science Separate Myths from Reality?

Scientific Method

Scientific Method

• Observation• Hypothesis

– Prediction

• Test Hypothesis– Experiment– Further Observations

• Conclusion

• for example…

Edward Jenner 1749-1823

• Smallpox– nasty disease which

killed millions

• Scientific Method– technique he used to

find a vaccine for it

First Step: Observation

• Smallpox is deadly (30-40% mortality rate)

First Step: Observation• But, those who survive the disease are immune

First Step: Observation• In addition, milkmaids do not get smallpox…

First Step: Observation• Milkmaids get cowpox from cows

Second Step: Hypothesis

•Jenner had an idea;

•Does Cowpox Makes You Immune to Smallpox?

Third Step: Make a Prediction

• Prediction: If you are exposed to cowpox, you will be immune to smallpox

• This hypothesis and prediction is based on Jenner’s milkmaid/cowpox observations

Fourth Step: Experiment

Fourth Step: Experiment• In 1796 Dr. Jenner tested his idea for a smallpox

vaccination on his gardener's son, an eight-year-old boy named James Phipps.

• He got the term "vacca" from the Latin word for "cow.“

• The boy did get Cowpox, but recovered from it within a few days. Jenner then waited eight weeks for the boy's body to build an immunity.

• To complete his experiment, Jenner exposed James to Smallpox. Amazingly, the boy did not contract the deadly disease, and the doctor claimed success!

Fifth Step: Conclusion

• Since getting Cowpox seemed to prevent anyone from getting Smallpox, Jenner had confirmation of his original hypothesis

• His hypothesis was supported by his experiments

Scientific Method• Really, it’s just a formal breakdown of how

our minds work when we’re trying to solve a problem.

• In life, we see a thing we don’t understand, we question it, we think of an explanation or idea, we test that explanation, and we evaluate our test.

Time for a Break….

Biology I - Initial Concepts• An overview:

1. Earth: Unity of Diversity

2. Evolution

3. Hierarchy of Organization

4. Emergent Properties

5. The Cellular Basis of Life

1. Earth: Unity of Diversity

• There are between 5 and 30 million species of living things on the earth.

• To date: ~1.5 million species have been identified.

~ 1.25 million animals

~ 250,000 plants

1. Earth: Unity of Diversity

• To organize all of these organisms, scientist classify species into categories.

• Taxonomy: the naming and classifying of organisms.

1. Earth: Unity of Diversity• Taxonomic groups are ranked into a hierarchy

from MOST to LEAST INCLUSIVE.

1. Kingdom Animalia the animals

2. Phylum Chordata backbones

3. Class Mammalia warm blooded

4. Order Carnivora eat meat

5. Family Canidae canine family

6. Genus Canus dog genus

7. Species lupus wolves

1. Earth: Unity of Diversity

• There are 6 Kingdoms of life:

1. Monera: bacteria

2. Archaebacteria: weird microbes

3. Protista: single celled animals

4. Plantae: plants

5. Fungi: yeast & molds

6. Animalia: animals

2. Evolution

• Life evolves & species change over time.

• Evolution is a change in the genes (DNA)

• All life is connected and can be traced back ~3.5 billion years on Earth.

• Evolution is the one biological theme that ties all together.

2. Evolution• Charles Darwin proposed Natural

Selection in his book: “On the Origin of Species by Means of

Natural Selection”

• Natural Selection:Environmental factors that favor the reproductive success of some individuals over others.

3. Hierarchy of Organization• Biological organization: Based on structural

levels from Least to Most Inclusive.

1. Atoms

2. Molecules

3. Organelles

4. Cells

5. Tissues

6. Organs

7. Organ systems

3. Hierarchy of Organization8. Organisms: species

9. Populations: localized groups of organisms belonging to the same species.

10. Community: populations of species living in the same area.

11. Ecosystem: community interactions

12. Biomes: large scale communities

13. Biosphere: the sum of all earth’s ecosystems.

4. Emergent Properties(what is life...)

A. Complexity

B. Reproduction

C. Growth and development

D. Transform energy to Food

E. Respond to stimuli

F. Adapts to the environment

5. The Cellular Basis of Life• Cells are the lowest level of structure capable

of all activities of life.

• Cell Doctrine/Theory: 1852 by Robert Hooke.

A. Cells are the basic unit of life.

B. Cells arise from pre-existing cells (mitosis).

C. Cells are surrounded by a membrane.

D. Cells transform energy (cellular respiration).

E. Cells have information retention and transfer in the form of genes (DNA - pass to offspring).

The End…