Characteristics of Life

1. All Life is Made of Cells

Cells are very small, very organized and covered by a membrane

Cells are the smallest unit of life.

2. All living things reproduce

3. Metabolism

What do scientists mean by metabolism?

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

• Living organisms carry out reactions to obtain and use energy.

4. Homeostasis

What is homeostasis?

• Homeostasis is the ability to maintain stable internal conditions.

What are some examples of this ability in humans?

Examples of Homeostasis

• In humans:– Shivering, sweating, feeling thirst or hunger

• Other animals that live in the cold have fur or a layer of fat to keep warm

• Bacteria that live in toxic environments like high acid lakes can neutralize the acid in their cells

Heredity

All living things pass on traits to their offspring

• The passing of traits from parents to offspring is called heredity

• A gene is a short section of DNA– A gene is the basic unit of heredity

• A mutation is a change in the DNA of a gene

All living species evolve

Evolution occurs in populations not individuals

• Evolution is a change in the inherited characters of a species over time.

• Natural Selection – the process in which organisms with the most favorable traits are more likely to survive and reproduce

Interdependence

All life depends on other living things

• All living things are connected

• Ecology is the branch of biology that studies the interactions of organisms with each other and with the nonliving part of their environment.