Characteristics of Living Things

1. COMPOSED OF CELLS 1. COMPOSED OF CELLS All living things are made up of at least one cell Cell –  Basic or smallest unit of life  Membrane bound structure in which all life processes are carried out  All organisms are organized at the cellular level.

2. IDENTIFY AND RESPOND TO STIMULI Stimulus is anything that may cause an organism to react - Loud noises, hunger Response - the reaction to something in the environment - Run/cover ears, Eat/hunt for food

Homeostasis – maintaining a stable internal environment Adaptation – Change in traits over time that help an organism survive better in an environment; inheritable changes

3. REPRODUCE  Asexual – single parent (cell) produces offspring identical to parent  Sexual – 2 parents (cells) produce unique offspring having characteristics or traits of each parent

 Offspring identical to parent (clone)  2 parent cells Reproduction Pass traits onto next generation (heredity)  1 parent cell  Used to make more cells for growth & replacement  Offspring show combination of parents (Unique)  Used to make new multi- celled organisms

4. Contain DNA 4. Contain DNA Deoxyribonucleic Acid Genetic material that contains the “blueprints” for each organism Provides directions for the making of proteins

5. OBTAIN & USE ENERGY Required to carry out life processes- making and breaking down food, movement of materials and building of cells Metabolism – the sum of all the chemical processes in an organism

METABOLISM The Sum of All Biochemical Processes Obtaining Nutrition Sun is the source of most energy Producers - Make food - photosynthesis Consumers – Eat other organisms Decomposers – Digest externally then absorb nutrients

2. Respiration – Mixing food with oxygen (O 2 ) to release energy Food + O 2 H 2 O + Waste Energy 3. Synthesis – Process of putting together or building up Making more cells – Growth Repair or Replace old cells 1. Digestion - Breaking down of large food particles into smaller pieces 4. Excretion – removal of wastes

6. GROWTH & DEVELOPMENT Growth is the increase in size of an organism Surface-to-volume ratio limits how large a cell can grow

Growth in Single-Celled Organisms In single-celled organisms growth occurs by an increase in cell size Cell can either stay big or divide

Growth in Multi-celled Organisms In multi-celled organisms growth occurs by production of new cells  Increases the total number of cells in the organism  Increases total surface to volume ratio

Development Development is all the changes an organism undergoes as it grows and matures Ex. Newborn puppies can’t see at birth Ex. Human babies develop the ability to speak and walk

Stages in Human Life Cycle Birth  Infancy  Childhood  Adolescence  Adulthood  Advanced Adulthood  Death 7. LIFE SPAN All organisms, and individual cells, have a specific life span Includes: Birth Death

4 Basic Needs of All Living Things

Food Needed to provide Energy to carry out life processes Ultimate source of energy is the sun Can get food as a producer, consumer or decomposer Provides raw materials for growth and repair

Water Cells contain ~70% water  Needed to release energy in food and for other biochemical reactions  Required for transporting materials throughout organism  Helps with dissolving or diluting waste products

Air or Gases  Carbon Dioxide (CO 2 ) required for photosynthesis - converting of energy from sun into food (glucose) organisms can use  Oxygen (O 2 ) required for respiration- releasing of energy from food (glucose) into energy organism can use  Other gases are needed in smaller amounts for various life processes; not required by all organisms

Environment Abiotic-non-living parts; physical features such as air, water, temperature (climate) Must contain all the needs for that organism to survive Biotic - living parts; other organisms that meet all 7 characteristics Living things may have to compete for their living space