What is Biology?

• Biology is the study of life

– More specifically: the scientific study of living organisms and their interactions with the environment

Why Should I Know About Biology?

• All living things on Earth are tied together by common traits and rely on one another for their common survival!

Q: Trees and people are both living organisms. Which branches of biology would study BOTH trees and humans?

A: Biochemistry, ecology, cell biology, genetics, evolutionary theory

What Kinds of Biology Are There?

• SOME of the branches of biology that scientists can specialize in:– Biochemistry: study of chemistry of life– Botany: study of plants– Ecology: study of how organisms interact

with each other and their environment– Cell Biology: study of life on the cellular

level– Genetics: study of heredity– Zoology: study of animals– Microbiology: study of microscopic

organisms– Neurobiology: study of the brain

What Do Biologists Do?

• Health Care

• Biotechnology

• Environmental Science

Characteristics of Life

• Organism – anything that possesses all 7

characteristics of life

1. Cellular organization

2. Homeostasis3. Metabolism4. Responsiveness5. Reproduction6. Heredity7. Growth and Development

Cellular Organization

• Cell– Smallest unit capable

of all life functions– Highly organized – TINY– Surrounded by a

membrane– Basic structure is the

same for ALL living organisms

• Scientists estimate that there are 5-10 MILLION different species!!

Homeostasis

• Maintenance of stable internal conditions in spite of changes in the external environment

– Species strive to survive at homeostasis

– Involves external and internal stimuli

– Without this ability to adjust organisms would not survive

Metabolism

• Sum of all chemical reactions carried out within a living organism

– Energy is the ability to do work– Almost all energy initially comes from

the SUN– Allows organisms to grow, reproduce,

and maintain homeostasis!

Response to Environment

• All organisms must respond to their external environment

– Stimulus• condition in the

environment that requires and organism to adjust

– Response • reaction to stimulus• How the organism

responds is imperative to the survival of the species and ultimately the environment

Reproduction• Production of offspring

– NOT essential to the individual organism, but IS necessary for the survival of the species!

Heredity

• When traits are passed on to offspring.– Why kids tend to look like their parents

– Inherited characteristics can change over generations. This process is known as evolution

Growth and Development

• Growth– results in an increase in the amount of

living material and formation of new structures

– Different parts grow at different time

• Development– changes that take place during the life

of an organisms– What changes have happened in you in

the last year?