Ch 1.1 The World of Biology• 1) Biology and You

The Study of life Bio=Life -ology= Study of

• –Biology is the study of life and can be used to both solve societal problems and explain aspects of our daily lives.

All Living Things Share Common Characteristics

II) Characteristics of Life

• Living things share the same characteristics:1. Basic Unit is the Cell

2. All Based On Universal Genetic Code (DNA)

3. Respond To Their Environment

4. Maintain Homeostasis

5. Obtain & Use Materials & Energy

6. Grow & Develop

7. They Reproduce

8. They Change over time

Characteristics of Organisms

All Organisms are made of Cells

1. Organization and Cells (– Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world.

– A cell is the smallest unit of an organism that can perform all life’s processes.

Single celled (unicellular ) organisms makeup most organisms on Earth.

They have everything they need to be self-sufficient.

In multi-cellular organisms, the cells specialize to perform specific functions (bone

cells, skin cells, muscle cells, root cells,leaf cells).

Smooth muscleNerve cell Leaf cell Red Blood Cell

Yeast cell

Cells Have a Genetic Code

2. Genetic Code

• DNA (deoxyribose nucleic acid) carries the genetic code for all organisms

• All organisms contain DNA

• DNA codes for the proteins that make up cells & do all the work

– organism can respond to a stimulus which is a physical or chemical change in the environment.

3. Response to Stimuli

Homeostasis– Homeostasis is the maintenance of a stable

level of internal conditions even though environmental conditions are constantly changing.

- pH, H2O content, Temperature, Food intake, Hormones.

Cells Require Food & Energy

4. Metabolism– Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment.

-All organisms need materials for energy

-Sunlight is the ultimate energy for life on Earth.

5. Growth and Development– The growth of living things results from the division and enlargement of cells. (Increase in Size)

– Development is the process by which an organism becomes a mature adult.

Organisms Reproduce to Pass on their Genetic Traits

6. Reproduction

– Living organisms pass on hereditary information from parents to offspring

Sexual- Genetic Material is exchanged

Asexual- No Exchange of genetic Material

7. Change Through Time

– Populations of living organisms (not individuals) evolve or change through time in order to survive .

- Organisms must adapt to changes in their environment or risk becoming extinct.