Characteristics of Life

An organism is the scientific term for a complete, individual living thing.

All organisms: are made of cells adjust to their environment reproduce have DNA use energy grow and develop

Organisms are made of cells. Cells are the building blocks, structural and functional units of all living things

Unicellular organisms are made of a single cell ex: paramecium, yeast, some algae algae paramecium yeast

Multicellular organisms are made of many cells and generally their cells have become highly specialized ex: humans, starfish, plants

2. Organisms adjust to their environment. In order to survive major changes, organisms must be able to adapt or make adjustments. Plant responses are tropisms. Ex: roots grow toward gravity, leaves and stems grow toward light

The internal environment of an organism must not change The internal environment of an organism must not change. The organism’s attempts to maintain its internal environment is called homeostasis. ex: external environment gets colder-we maintain homeostasis by shivering and jumping up and down Homeostasis involves everything from body temperature, to pH, to fluid levels.

3. Organisms reproduce. Since no organism lives forever the survival of a species depends on reproduction. Sexual reproduction involves 2 cells from different individuals uniting to form a new cell, the zygote.

Asexual reproduction occurs when a single organism reproduces without the aid of another.

4. All organisms have DNA DNA controls cells. The passing of DNA from parents to offspring is known as heredity.

5. Living things obtain and use energy. The sun is the major source of energy for life on earth. Chemical energy is used to carry out the activities of its cells.

Metabolism is the sum of the ways an organism gets and uses energy.

6. Living things grow and develop. Growth occurs when organisms take in materials from its surroundings, break them down, and build new cells from them.

Organisms grow at a certain rate and they develop (change) as they grow.