Biology the Characteristics of Life What is Biology

Biology & the Characteristics of Life

What is Biology? a. Study of: – – – Life Origins and history of life and once-living things Structures of living things How living things interact with one another How living things function b. Biologists: –Study the diversity of life –Research diseases –Develop technologies –Improve agriculture –Preserve the environment

What is Life? a. Living things are called ORGANISMS b. All organisms must have ALL of the characteristics of life… – Organization (DNA/cells/organ systems) – Reproduce – Change (growth/development) – Adjust (homeostasis/stimulus & response) – Adapt/evolve

ORGANIZATION a. DNA (Deoxyribonucleic acid) Genetic material contained within each cell of a living organism. Carries the information needed to control life processes within living organisms. Allows for passage of traits from parent to offspring.

ORGANIZATION b. Cellular Organization Cell: A collection of matter enclosed by a barrier that separates the cell from its surroundings. Organisms can be unicellular (single-celled) or multi-cellular (many cells) c. Higher Level Organization – Specialized cells are organized into groups that work together called tissues Tissues are organized into organs – Organ systems work together to support an organism

REPRODUCTION a. The production of offspring 1. Is essential for the survival of a species 2. Two types: Asexual: The new organism has a single parent **Offspring & their parent will have the SAME traits Sexual: Two cells from different parents unite to produce the first cell of the new organism. **Offspring & their parents will DIFFER in their traits.

CHANGE • Organisms have life cycles b which they change over time GROWTH: An increase in the amount of living material & the formation of new structures. DEVELOPMENT: All of the changes (growth) that takes place during the life of an organism.

• All organisms live & respond to changes in their environment • Variables (both living & nonliving) cause organisms to make internal as well as external adjustments • STIMULUS – A condition in the environment that requires an organism to change or adjust » Ex. light, temperature, odor, sound, gravity, heat, water, pressure • RESPONSE – A reaction to a stimulus ADJUST

ADJUST • Organisms need nourishment and energy to complete life processes 1. Anabolism –Process of building up complex substances from simpler substances (ex. Photosynthesis) 2. Catabolism –Process of breaking down complex substances into simpler substances to release energy (ex. Cellular Respiration & Digestion) 3. Metabolism –The combination of chemical reactions through which organisms build up or breakdown materials as it carries out its life processes 4. Different organisms obtain energy in different ways (plants vs. animals vs. bacteria)

ADJUST • HOMEOSTASIS –Process by which organisms keep their internal conditions relatively stable. - Homeostasis is constantly threatened by environmental changes…long term disruption to homeostasis will lead to the death of the organism.

ADAPTATION & EVOLUTION • ADAPTATION – Any structure, behavior, or internal process that enables an organism to respond to stimuli and better survive in an environment. • EVOLUTION - Change over time • As a whole, a group of organisms will change over time in response to changes in their environment