Organization of Life

Levels of Organization The different branches of biology can be classified based on different levels of complexity Each “level” is made up of smaller component, and usually contributes to a larger system.

Levels- smallest to biggest 1.Molecules- groups of atoms; the smallest unit of most chemical compounds 2.Cells- smallest functional unit of life. Basic units of structure and function. 3.Tissues- composed of specialized cells which perform a specific function – Ex. Blood, muscle, nerve

Levels- smallest to biggest 4.Organs- groups of specialized tissues that perform a specific function – Ex. Heart, brain, liver, skin 5.Organ Systems- consist of different organs that work together to perform a specific function – Ex. Digestive, nervous 6.Organism- any single multi-cellular living thing

Getting Bigger… Population: Organisms of a species interact to form a population Community: Populations of different species that live together in an area create a community. Ecosystem: The community and it’s non-living environment make up an ecosystem.

Levels of Structural Organization Figure 1.1, step 1 Molecules Atoms Chemical level Atoms combine to form molecules

Levels of Structural Organization Figure 1.1, step 2 Smooth muscle cell Molecules Atoms Cellular level Cells are made up of molecules Chemical level Atoms combine to form molecules

Levels of Structural Organization Figure 1.1, step 3 Smooth muscle cell Molecules Atoms Smooth muscle tissue Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells Chemical level Atoms combine to form molecules

Levels of Structural Organization Figure 1.1, step 4 Smooth muscle cell Molecules Atoms Smooth muscle tissue Epithelial tissue Smooth muscle tissue Connective tissue Blood vessel (organ) Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells Organ level Organs are made up of different types of tissues Chemical level Atoms combine to form molecules

Levels of Structural Organization Figure 1.1, step 5 Smooth muscle cell Molecules Atoms Smooth muscle tissue Epithelial tissue Smooth muscle tissue Connective tissue Blood vessel (organ) Cardio- vascular system Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells Organ level Organs are made up of different types of tissues Organ system level Organ systems consist of different organs that work together closely Chemical level Atoms combine to form molecules

Levels of Structural Organization Figure 1.1, step 6 Smooth muscle cell Molecules Atoms Smooth muscle tissue Epithelial tissue Smooth muscle tissue Connective tissue Blood vessel (organ) Cardio- vascular system Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells Organ level Organs are made up of different types of tissues Organ system level Organ systems consist of different organs that work together closely Organismal level Human organisms are made up of many organ systems Chemical level Atoms combine to form molecules

Overview of Organ Systems Pg 893

Skeletal System Purpose – Protects and supports body organs – Provides muscle attachment for movement – Site of blood cell formation – Stores minerals Structures: – Bones, cartilage, ligaments, tendons Diseases: – Osteoporosis, leukemia

Figure 1.2c Muscular System Purpose: – Produces movement – Maintains posture – Produces heat Muscles can only contract (pull) to produce movement Structures: – Skeletal, smooth, and cardiac muscle

Nervous System Purpose: – Fast-acting control system – Detect and react to changes in the environment – Controls various activities in the organism Main Organs: – Brain, spinal cord, sense organs Diseases: – Alzheimer’s, stroke, aneurysms, Parkinson’s

Endocrine System Purpose: – Produces chemicals called hormones that control various activities in the organism Hormones control: – Growth – Reproduction – Metabolism Main organs: – Pancreas, pituitary gland, adrenals, ovaries, testes Diseases : – Diabetes, dwarfism, gigantism

Circulatory System Purpose: – Transports materials to all the cells in an organism via blood pumped by heart Oxygen Carbon dioxide Nutrients Wastes Main organ- heart Diseases: – Heart Attack, arteriosclerosis, embolisms, hemophilia

Lymphatic System Purpose – Returns fluids to blood vessels – Cleanses the blood – Involved in immunity Structures: – White blood cells, spleen, lymph nodes, lymph vessels

Respiratory System Purpose – A gas exchange system. Brings in Oxygen and removes Carbon Dioxide Main organ: – Lungs, diaphragm, trachea Diseases: – Asthma, bronchitis, cancer

Digestive System Purpose: – Breaks down food; turns large molecules into smaller ones – Allows for nutrient absorption into blood – Eliminates indigestible material Main Organs: – Stomach, liver, pancreas, intestines Diseases: – Ulcers, appendicitis, cancer

Excretory System Urinary – Eliminates nitrogenous wastes – Maintains acid-base balance – Regulates water and electrolytes Structures: – Skin, lungs, kidneys, bladder

Reproductive System Purpose – Produces reproductive cells Structures: – Testes, ovaries