<span>Levels of OrganizationIn unicellular (single-celled) organisms,
the single cell performs all life functions. It functions independently.
However, multicellular (many celled) organisms have various levels of
organization within them. Individual cells may perform specific
functions and also work together for the good of the entire organism.
The cells become dependent on one another.Multicellular organisms have
the following 5 levels of organization ranging from simplest to most
complex:<span><span>LEVEL 1 - Cells<span><span>Are the basic unit of structure and function in living things. </span>May serve a specific function within the organismExamples- blood cells, nerve cells, bone cells, etc.</span></span><span>LEVEL 2 - Tissues<span>Made up of cells that are similar in structure and function and which work together to perform a specific activity Examples - blood, nervous, bone, etc. Humans have 4 basic tissues: connective, epithelial, muscle, and nerve.</span></span><span>LEVEL 3 - OrgansMade up of tissues that work together to perform a specific activityExamples - heart, brain, skin, etc.</span><span>LEVEL4 - Organ Systems <span>Groups of two or more tissues that work together to perform a specific function for the organism. Examples - circulatory system, nervous system, skeletal system, etc. The
Human body has 11 organ systems - circulatory, digestive, endocrine,
excretory (urinary), immune(lymphatic), integumentary, muscular,
nervous, reproductive, respiratory, and skeletal.</span></span><span> LEVEL 5 - Organisms <span> Entire
living things that can carry out all basic life processes. Meaning they
can take in materials, release energy from food, release wastes, grow,
respond to the environment, and reproduce. <span>Usually made up of organ systems, but an organism may be made up of only one cell such as bacteria or protist. </span>Examples - bacteria, amoeba, mushroom, sunflower, human</span></span></span></span>
The giant sequoia (<em>Sequoiadendron giganteum</em>) are the most massive trees in the world, and the tallest is one sequoia called "General Sherman" with a height of 83.8 m. "General Sherman" is estimated to be 2,000 years old, and is estimated that a sequoia tree can live up to 3,500 years. Therefore, an 80-meter sequoia tree in the forest most likely will have more than 1,000 years.
The indentation on the medial surface of each lung through which
pulmonary and systemic blood vessels, bronchi, lymphatic vessels, and
nerves enter and
leave is called the hilum
Transpiration in plants requires adhesion of water molecules to cellulose, cohesion between water molecules, evaporation of water molecules and transport through tracheids. Cohesion between water molecules is as a result of hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule. Transpiration involves the release of water through the leaves in pores called stomata, this serves as a method of excretion of excess water and diffused gases.
