Biology Review for the GHSGT Characteristics of Life

Characteristics of Life • • • 1. Cells 2. Sensitivity (response to stimuli) 3. Growth 4. Homeostasis (stable internal environment) 5. Reproduction 6. Metabolism (transformation and use of energy) • 7. Adaptation

Characteristics of Life - Cells • Cells make up all living things • Can sometimes organize into complex structures • Multicellular organisms have many cells and unicellular organisms have only one cell.

Characteristics of Life - Sensitivity • Organisms respond to stimuli in the environment • A stimulus is a change in the environment • Responses to stimuli include a plant that grows toward a light source, or an animals that flees from a predator

Characteristics of Life - Growth • Organisms change over their lifetime. • This growth may be characterized by: – an increase in size – the development of new physical structures – the refinement of reasoning or behavior

Characteristics of Life - Homeostasis • Homeostasis is the ability of an organism to maintain a steady internal state, regardless of external influence • Organisms must maintain an internal environment that is suitable for life – Amount of fluids, salts, hormones, food

Characteristics of Life - Reproduction • All live things must be able to reproduce. • Two types: – Sexual – two organisms create offspring – Asexual – One organism is capable of creating offspring itself

Characteristics of Life - Metabolism • Organisms get their energy from their environment • Metabolism- the sum of all chemical reactions within a cell or organism – Includes: • extracting energy from environment • using that energy • Disposing of waste by-products

Characteristics of Life - Adaptation • Over time, organisms become specially suited to their particular environment – Occur slowly over time

Life Processes • Living things also carry out life processes. – Specific events that allow cells to grow, respond to stimuli, maintain homeostasis, reproduce, metabolize, and adapt • Non-living things cannot carry out these processes

Life Processes • Nutrition- the use of nutrients by an organism • Digestion- the process that breaks large food molecules into forms that can be used by the cell • Absorption- the ability of a cell to take in nutrients, water, gases and other substances from it’s surroundings

Life Processes • Transport- the movement of nutrients, water, gases and other substances into and out of the cell • Biosynthesis- the cellular process of building new chemical compounds for the purpose of growth, repair and reproduction

Life Processes • Secretion- the release of substances fron a cell • Respiration- the release of energy from chemical breakdown of compounds within the cell • Excretion- the ability of the cell to rid itself of waste products

Life Processes • Response- the ability of a cell to react to stimuli from its environment • Reproduction- the process of fission in which one cell divides to form two identical new cells • Photosynthesis- the cellular process in which a plant makes food from water and carbon dioxide using energy from the sun

Characteristics of Life - Quiz • Definitions: – Stimulus – Life – Response – Homeostasis – Sexual reproduction – Asexual reproduction – Metabolism

Characteristics of Life - Quiz • 1. Which is NOT a characteristic of life? – A. reproduction – B. homeostasis – C. sensitivity – D. transport

Characteristics of Life - Quiz • 2. Which of the following is an example of how organisms maintain homeostasis? – A. a damaged skin cell dividing into two newer cells – B. a human shivering in cold weather – C. a crow learning to retrieve a food reward in a laboratory experiment – D. finches in the Galapagos developing different types of beaks

Characteristics of Life - Quiz • 3. A runner eats a large pasta dinner the night before a big race. In this example, which characteristic of life is the runner using to help her win the race? – A. digestion – B. homeostasis – C. sensitivity – D. metabolism

Characteristics of Life - Quiz • 4. How are life processes different from characteristics of life? – A. Life processes are the specific actions that help organisms maintain characteristics of life – B. Characteristics of life are the specific actions that help organisms maintain life processes. – C. Only organisms that show characteristics of life carry out life processes. – D. Life process and characteristics are the exact same

Characteristics of Life - Quiz • 5. List the seven characteristics all living organisms show. • 6. Based on what you know, how would you explain that fact that fire is not considered alive even though it grows and uses oxygen? • 7. Which life processes have to do with obtaining the processing food?