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* Covers Chapter 4 Structure and Function of the Cell Pages 68 - 91 * * Scientists have studied the cells of over 2 million different species * But, scientists estimate there are over 40 million species on Earth! *After studying so many species, scientists observed that although cell size, shape and function is very diverse, all cells have some similarities. * *All cells are surrounded by a protective layer *Known as a cell membrane *Def. – thin layer that forms the outer boundary of the cell *Protects cell by being selectively permeable *Def. – only allows certain substances into the cell *All cells contain cytoplasm *Cytoplasm – anything that is inside the cell (except nucleus), includes cytosol *Cytosol – gelatin-like fluid inside the cell * *All cells contain genetic material (DNA) *How DNA is stored is how scientists classify the type of cell * Prokaryotic cell – DNA not contained * Eukaryotic cell – DNA contained in a nucleus * *All cells contain internal cellular structures known as organelles *The kinds of organelles they contain is how scientists classify the type of cell *Prokaryotic cells do not contain organelles that are surrounded by a membrane * Prokaryote Genetic Information (DNA) Eukaryote • Clumped, not contained in an organelle • Single chromosome • DNA stored in nucleus • Chromosomes usually come in pairs Nucleus • No nucleus • Has a nucleoid region • Has a nucleus Organelles • Only has organelles WITHOUT membranes • Contains organelles with and without membranes • Membrane is same material as cell membrane Examples • Bacteria • Protist, Fungus, Plant, Animals * * Covers Chapter 18, Classification *Pages 336 – 353 * * Every year, scientists discover thousands of new species. * By examining the organisms’ cells, structure, habitat, feeding patterns, etc., the organisms are grouped into different categories * TAXONOMY – science of grouping organisms according to their characteristics and evolutionary history *Early Taxonomy *Classified organisms according to where they lived, internal structures, external structures *Organisms were given common names *Could incorrectly describe the organism *Same organism could have different name around the world * Today, we use many techniques and information to classify organisms. Some examples: *Morphology *Def. – study of internal and external structures *Examples: type of cell, type of organelles, type and arrangement of tissues and organs, etc. *Phylogeny *Def. – evolutionary history of a species, tries to group similar species together *Fossil record *Provides clues about the evolution of the species *Embryo development *Protein structure *DNA sequence *Number of chromosomes *Once species are classified, scientist can use the information to study relationships between similar species *Phylogenetic Tree *Also known as evolutionary tree *Def. – “Family Tree” showing evolutionary relationship between various species *Changes as new information is discovered *Cladogram *Diagram showing the order that new features evolved in various species * *Based on the classification and naming system devised in the 1700s by Carolus Linnaeus (1707 – 1778) *Levels of Classification – Each category gets more specific *Domain *Kingdom *Phylum *Class *Order *Family *Genus *Species * * Binomial nomenclature – Scientific naming system * Linnaeus’ classification gave every organism a scientific name * The scientific name has 2 parts 1. Genus 2. species identifier * Genus name is always capitalized * species name is never capitalized * Homo sapiens * Scientific name must be either: * Underlined : Homo sapiens OR Italicized: Homo sapiens * * 3 Domains * Domain Archaea * Kingdom Archaebacteria * Domain Bacteria * Kingdom Eubacteria * Domain Eukarya * Includes all eukaryotic organisms * Kingdom Protista * Kingdom Fungi * Kingdom Plantae * Kingdom Animalia *