Life Structure and Classification What are living things like? Any living thing is an organism Organisms : are organized : grow and develop : respond : maintain homeostasis :use energy : reproduce

Organized All living organisms are composed of cells Cells are smallest unit of life that carries on the function of life Cells take in materials and use them in complex ways Have orderly structure and instruction for transfer of heriditary material

Living Things grow and Develope Single cell organisms increase cell size Multi-celled organisms grow by increasing number of cells Changes that take place during lifetime is known as development Figure 2 shows examples of development Life span is the length of time an organism is expected to live

Living things Respond Living things interact with their surroundings Anything that causes change in an organism is a stimulus and the reaction to that is a response Organisms must respond to stimuli to carry on daily activity and to survive

Maintain Homeostasis Inside cells they must respond to stimuli within (water or food levels within) Cells internally make adjustments This regulation of an organism’s internal life maintaining conditions that is in response to it’s environment is called homeostasis

Living things use energy All energy for cells originates from the sun Plants use sun directly to produce energy (photosynthesis) where H2O + CO2 produces C6H12O6 (carbohydrates) and O2 Animals and some other organisms take in carbohydrates and oxygen to produce its energy Some bacteria deep in dark ocean floors use stored energy in chemical compounds to make food

Living things must reproduce In order for an organism to continue to its own kind it must be able to reproduce itself

What do living things need to survive Place to live Needs water Water transport minerals within and between cells Water is released by organisms and homeostasis is maintained Needs food source Animals need to take in food, where plants produce their own food Organisms die and are decomposed by other organisms that are reused again

How are living things classified section 2 Carolus Linnaeus Developed a system of organizing organisms by similar structure in system called Binomial Nomenclature. Used Scientific Names rather than common names Modern classification use structure, hereditary information and early stages of development

Binomial Nomenclature Two word naming system (latin names) First word is the genus name (contain similar species) Second word is the species name Can describe a feature, place or honor an individual Ambystoma tigrinum (salamander named because of tiger stripes) Organisms of same species can reproduce amongst themselves

Scientific Names Why they are important Help avoid confusion with common names Organisms with similar evolutionary histories are group together Gives descriptive information about species (tiger salamander) It is organized efficiently

Classification Order Organisms are classified in following order: Kingdom Phylum (Division in plants) Class Order Family Genus species

Modern Classification Today scientist use phylogeny to classify organisms Uses fossils, evolutionary history and changes over time to classify Smallest group is a species Broadest group is Kingdom Figure 6 in book classifies a brottle nosed dolphin

Tools for Identifying Organisms Field guides and dichotomous keys aide to identify organisms Dichotomous key (use 2 characteristics that you choose between that leads to identification of organisms) The key will lead to genus-species final name of organism

Cell Structure section 3 Viewing cell structure First developed by using two magnifying glasses together to see larger view of cells Leeuwenhoek (Dutch) saw inside cells (1600’s) called them beasties

Development of Cell Theory Hooke in 1665 sliced a piece of cork and saw empty space he called cells 1830 Scheiden used a microscope to study plant parts and called them cells Schwann observed animal cells Both men combined their ideas and were convinced all living things are made of cells Mid 1800’s Virchow proposed that cells divide and every cell comes from a cell that already existed

Cell Theory table 2 (page 221) All Cells are made up of one or more cells Cells are the basic unit of organization in organism All Cells come from pre-existing cells

Cell organization Scientists divide cells that have a membrane bound structure and those that don’t Cells without a membrane are called prokaryote cells Cells with a membrane around the cell are called eukaryote cells Each cell performs specific functions but all cells must take in nutrients, store, produce and breakdown substances, take in and use energy Structure of cells perform certain functions

Cell Wall Tough rigid outer coverings that protect cells and give them shape Found in all plants, algae, fungi and most bacteria Plants cell wall contain mostly cellulose (carbohydrate) and allows water and nutrients in and out Pectin (found in plant cell walls) is glue-like structure that has thick structure (jams and jellies) Lignin (makes cell walls rigid) found mostly in plant cells that aide in supporting plants

Cell Membrane All cells contain a cell membrane It is the outermost covering of cells unless they have a cell wall Regulates interactions between cells and environment Allows nutrients to move in and wastes to leave cell

Cytoplasm Gell-like substance inside cell membrane is called cytoplasm Life processes take place here Prokaryote cells cytoplasm contains the hereditary material All organelles are located here Cytoskeleton found in cytoplasm is made of proteins that help cell change shape, enable some cells to move

Manufacture of Proteins in Cells Every cell activity involves proteins Proteins are part of cell membrane and are part of all chemical reactions in cell Ribosomes produce protein in cells Found in cytoplasm Get their instruction from hereditary material that tells them how, when and in what order to make specific proteins

Membrane-bound Organelles Organelles are structure in cytoplasm that carry out life functions in cells Found in cytoplasm of eukaryotic cells Nucleus is largest organelle Ribosomes are not membrane bound but are considered an organelle

Organelles that produce Energy Chloroplasts: (organelle found in plants) Contain chylorophyll (green pigments) that captures sunlight to make sugars called glucose Captured light energy is stored in glucose as chemical energy where plants utilizes glucose to carry out life functions in cells

Organelles that produce Energy Organelle that releases energy is Mitochondria Food (glucose and carbohydrates) is broken down into CO2 and H2O and releases energy Sometimes called the powerhouse organelle because it provides the energy for cells All plants and animal cells have these

Organelles that process, transport and store materials Endoplasmic reticulum (ER) takes up considerable amount of space that process and move materials around cell like a conveyor belt Rough ER contains ribosomes where protein is made and moved in cell Smooth ER process lipids and oils that store energy

Organelles that process, transport and store materials After proteins is made they are transferred to Golgi bodies where they are packaged and moved to areas of cells in vesicles Materials are also moved to outer membrane for release outside of cell Vacuoles also are organelles that store water, waste products, food and other cell materials

Organelles that Recycle Lysosomes are structures that break down food molecules, cell waste, worn- out cell parts and viruses Chemicals released from lysosomes break down food and dead cells These chemicals are contained in lysosomes and when a cell dies, the chemicals are released and break down the dead cell

Many Celled Organisms Many celled organisms rely of other cells to perform all life functions Tissue is a group of similar cells that work together to do one job Tissues are organized into organs. Organs are a group of tissues that work together to perform a function (heart..nerve, blood and cardic muscle tissue) Group of organs working together perform a certain function is an organ system Organ systems work together to make up many celled organisms (heart, arteries, veins, and capillaries)

Viruses section 4 Viruses causes many diseases Viruses are non-living strands of hereditary material surrounded by a protein coat Do not have nucleus, other organelles or a cell membrane Viruses rely on host cells to live inside (living cells) Have two kinds of viruses: Active and Latent

Active Viruses Occurs when virus enters host cell and immediately begins to make new viruses Destroys the host cells when it makes new viruses Virus uses host cell to duplicate its hereditary material and later releases duplicated virus and kills host cell when they are released Figure 17 page 232

Latent Viruses Some viruses enter host cell and remain inactive for a period of time Does not immediately cause the host cell to duplicate new virus At a later time it may begin to duplicate and release new viruses that kill the host cell AIDS, cold sores are examples

How do viruses affect organisms Viruses attach specific cells that match host cells Many times viruses only attach to certain host cells (potato leafroll) Some viruses can affect numerous organisms (rabies) Viruses are moved by wind and inhaled where they attach Figure 18 page 233

Treating/Preventing Viral Diseases Treatment difficult because antibiotics do not kill viruses Prevention is best method of avoiding viral infections (eliminate mosquito to fight yellow fever)

Natural Immunity Human bodies fight viral infections by making interferons Interferons are proteins that make a protective covering for cells that are infected (produced by healthy cells to protect affected cells)

Vaccines Vaccines are weakened viruses that can’t enter host cells and duplicate, but cells begin to make interferons that protect all cells from infection Measles, mumps, small pox, chicken pox, polio, and rabies Found vaccine by taking weakened cow pox cells and entering them into healthy people to prevent small pox (1786) Jenner

Virus Research AIDS is a disease that is caused by human immuno-deficiency virus (HIV) AIDS (acquired immune deficiency syndrome) The HIV virus weakens the immune system and body can’t fight infections like pneumonia, TB People usually die from weakened system rather than disease