How do we define biology?

Biology has different branches• Biochemistry: chemistry of

life• Ecology: how organisms

interact with each other and their environment

• Cell biology: life on the cellular level

• Genetics: how organisms pass traits to their offspring

Biology has different branches, cont’d

• Evolution: changes in organisms over time

• Microbiology: microscopic organisms

• Botany: plants

• Zoology: animals

• Physiology: functions of living organisms and their parts

Microscopy

http://www.classzone.com/cz/books/bio_07/resources/htmls/animated_biology/unit1/bio_ch01_0021_ab_cells.html

Light microscope

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Electron microscope

Life is Diverse

Properties of Life

Living Things

• Are organized, and are made of one or more cells (Cellular Organization)

• Maintain stable internal conditions (Homeostasis)

•Are capable of Reproduction

•Exhibit Growth and development

•Respond to their environment(Responsiveness)

• Pass traits to offspring (Heredity)

• Use energy. Metabolism is the sum of all chemical reactions carried out in an organism.

Examples

• Hummingbirds feed almost constantly to supply energy to their racing wings and hearts.

• Metabolism, homeostasis

• A butterfly emerges from a cocoon.

• Development

A bacterium divides into new cells every 15 minutes

• Reproduction

•  An elephant's large ears allow the blood in the ears to be cooled by as much as 10 degrees.

• Homeostasis, responsiveness

• A pill bug rolls into a ball when touched.

• Responsiveness

• Earthworms are made of specialized cells, such as digestive cells, muscle cells, skin cells, etc.

• Cellular Organization

•A female frog lays many eggs at a time

• Reproduction

A toad burrows into the mud to prevent water loss during extended

periods of dry weather.

Homeostasis, Responsiveness

An amoeba is composed of a single cell.

Cellular Organization

A child inherits cystic fibrosis from her parents

• Heredity

Mitochondria in a cell release energy from sugars

• Metabolism, cellular organization, homeostasis

A Venus flytrap traps an insect between its leaves.

Responsiveness

Stimulus or response?• The bell rings at the end of a class period• Your dog runs into the kitchen when you

open a can• A paramecium backs up and moves away

when it encounters an obstacle. • A plant grows toward the window• A baby hears a loud noise• You pull your hand away after touching the

hot oven

What is a SPECIES?

• A group of organisms that can interbreed and produce fertile offspring in nature.

• Example: All dogs are the same species

• Dogs and wolves are not the same species