The Characteristics of Life! What is it to be alive???

Biology: The Study of Life Biology is the study of living things Species: a group of living things that can breed together in the wild Best estimate: about 10-15 million species Only 1.5 million have been studied & named Life is diverse yet all living things share common characteristics What is alive?

All living things have 8 characteristics in common: Living things are made of at least one cell. Bacteria Yeast

2. Living things are organized there are levels of organization in an organism. Cells Tissue Organ Organ system Organism Atoms-molecules-cells (lowest level with characteristics of life)-tissues-organs-organ system-organism-population-community-ecosystem

3. Living things acquire materials and energy -they metabolize What are materials? Energy: the capacity to do work →It takes work to stay organized & carry out functions. Living things need outside materials & energy to stay organized & carry on activities. Plants use CO2, water, & solar energy to make food. Animals get energy from food.

4. Living things grow Living things add mass to themselves (more material) Cells grow larger Animals grow and develop Bodies are repaired TO MAKE MORE OF THE SAME TYPE OF ORGANISMS. Single-celled organisms reproduce asexually by dividing & each new cell has an exact copy of the DNA. Multicelluar organisms usually reproduce sexually—each parent contributes about ½ of the genes of the offspring (mixture of DNA)

5. Living things reproduce. Asexual reproduction no genetic diversity Sexual reproduction Two parents allows for diversity

6. Living things are homeostatic Homeostasis: staying the same (ability to maintain relatively constant internal conditions) Other Examples? Examples: temperature, blood pH, correct amount of water. All organ systems participate in homeostasis.

7. Heredity All living things pass genetic information from parents to offspring Genes (DNA)—the instructions for making everything in the organism

8. Response to Stimulus All living things respond to stimuli in their own ways.

1: Give 5 examples of life. These are biotic things. 2: Give 4 examples of non-living, or abiotic things. 3. What is the smallest living thing.