Diversity and Function
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Diversity and Function Cellular Organization, Structure, Function, & Classification
Binomial Nomenclature • In the binomial system of classification, each species is given a two word name. • First word describes the genus to which the organism belongs (Capitalized) • Second word is the specific epithet (never capitalized; underlined or italicized) • Example: “Grey Wolf” = Canis lupus
Q: Why don’t we just call things by their common names? Though it would seem to be easier to do that, there are some REAL problems with that: • Common names can change from place-to-place. (What we call a “Marsh Marigold” is called a “King’s Cup Flower” on the east coast.) • Common names are sometimes entirely inaccurate. For example, “Ringworm” isn’t a worm at all!
Some common names: Ringworm Horned Toad Slow worm OR blindsnake Velvet Ant
Actual type of organism: Fungus Lizard Burrowing Lizard Wingless Wasp
Organism name:Apis pubescens, thorace subgriseo, abdominae fusco, pedibus posteuis, glabris, utrinque margine ciliatus Name meaning:Bee with soft short hairs, grey chest, dark brown abdomen, legs with no hair and small sacs with hair-like growth along the edges.
Taxonomy • Taxonomy is the field of biology concerned with classifying organisms on similarities or differences. • A taxon is any of the hierarchical categories that an organism can be placed in for classification purposes. • Carl Linnaeus came up with the binomial system of classification around 1735, & thus founded modern taxonomy.
Taxon’s in order: Killers Prefer Camo Over Frilly Ghillie Suits Kingdom King Phylum Phillip Class Came OrderOver FamilyFor GenusGood SpecieSoup
Tissues • A group of similar cells that work together to perform a specific function. • Example: Skeletal Muscle tissue (contractile cells which work together for locomotion) • 4 major types of tissues…
Three kinds of body plans • Bilateral • Radial • Asymmetrical
Radial symmetry • The body parts are arranged like pieces of a pie around an imaginary central axis
Bilateral symmetry • Means that an animal can be divided equally by a single cut and has mirror-image right and left sides. • Dorsal – back • Ventral – bottom • Lateral - sides
Asymmetrical body plan • No clear body symmetry plan. • Ex: Sponges & corals
The 6 Kingdoms: • Plantae (Plants) • Protista (Protists) • Fungi (Fungus) • Animalia (Animals) • Eubacteria • Archaebacteria
9 major Phyla of the animal kingdom: • Porifera – “Pore Bearers” • Cnidaria – “Stinging Tentacles” • Platyhelminthes – “Flat Worms” • Annelida – “Segmented Worms” • Nematoda – “Round Worms” • Mollusca – “Soft Bodied” • Arthropoda – “Jointed Legs” • Echinodermata – “Spiny Skin” • Chordata – “Spinal Cord”
Animals are multicellular, heterotrophic eukaryotes that obtain nutrients by ingestion. • Lack cell walls • Cells are held together by extracellular matrix proteins and junctions (ex: lamanin protein) • Have muscle cells for movement and nerve cells for conducting impulses • Diploid and reproduce sexually • Egg and sperm are the only haploid cells There are 9 major Phyla and many smaller Phyla (in terms of numbers) in the Animal Kingdom.
Phylum Porifera: • The body of a sponge is covered with pore containing cells. • Invertebrate animals that live mostly in saltwater, though there are a few freshwater species. • Non-motile and depend on moving water currents. Water, food and oxygen move in : CO2 and wastes move out
Osculum- Opening that outgoing water and wastes move through to exit the sponge • Spicules- thin spiny structures that make up the skeleton of sponges. • Reproduction: • Sexual- egg and sperm are released into the water, forming new sponges. Asexual- budding, a piece breaks off and forms a new sponge which is an exact copy of the parent
Sponges have a simple porous body • Organisms that have no true tissues are classified as parazoan. • Simplest of all animals, have no nerves or muscles; don’t have tissues because the cells are relatively unspecialized • Suspension feeders – feed by collecting bacteria from water that streams through their bodies then engulfing it by phagocytosis.
Parazoa or Eumetazoa? • Parazoa – Animals with no true tissues (which means they have few to no specialized cells); • Example: Sponges. • Eumetazoa – Animals that have specialized cells which are organized into tissues; • Example: All animals other than sponges.
Phylum Cnidaria – “Stinging tentacles” • Radial symmetry • This group includes hydras, jellies, sea anemones and corals. • Carnivores that use their tentacles to capture small animals and protists, and push the prey into their mouths • Have stinger cells on the surface of the tentacles that function in defense and prey capture • Have a digestive cavity and true tissues.
There are 3 different phylums of worms alone • Phylum Platyhelminthes – “Flatworms” • Phylum Nematoda – “Roundworms” • Phylum Annelida – “Segmented worms” • Each phylum has it’s own defining characteristics, as well as different body plans.
Flatworms Roundworms Segmented worms
Phylum Platyhelminthes- “Flatworms” • Acoelomates that exhibit a touch of cephalization. • Roughly 20,000 species • There are both free living and parasitic forms • Have an incomplete digestive tract (gastrovascular cavity) • Simplest bilateral animals
3 main types of flatworms you should be familiar with: • Flukes – Parasitic flatworms that alternate between sexual & asexual reproductive life cycles. • Planarians – Free living marine carnivores • Tapeworms – Type of parasitic flatworm that inhabits the digestive tract (usually) of vertebrates
Flukes (below) Moose liver fluke (above) Human blood fluke
Class Cestoda - Tapeworms -“Head” region is called the “scolex” (used for attachment) - Body made up of thin, tape-like segments called proglottids. • Inhabit the digestive tracts of vertebrate animals including reptiles, birds, and mammals • Have no digestive tract • Live in partially digested food in the intestine of their hosts and absorb nutrients across their body surface • Several kinds infect humans and can grow up to 6m in length.
Phylum Nematoda- “Roundworms” • Cylindrical worms with a blunt head and tapered tail • Covered by a tough cuticle that resists drying and crushing (molts when it grows) • Complete digestive tract • 90,000 known species • Trichinosis (most commonly found in pork) is caused by a roundworm called Trichinella; humans can contract the disease by ingesting infected meat.
Phylum Annelida – Segmented Worms • Around 15,000 species • Includes earthworms and leeches • Earthworms till the soil and improve its texture • Leeches secrete saliva into the wound that contains a strong anesthetic and an anticoagulant.
Annelids have segmented bodies • The subdivision of the body along its length into a series of repeated parts. • Allows greater flexibility and mobility
Phylum Mollusca – “Soft Body” • Coelomate body plan with a full digestive system. • More than 150,000 known species • Includes snails, slugs, oysters, clams, octopuses and squids • Most have a soft body protected by a hard shell • Bivalves, like oysters & clams, are mollusks that have hinged shells that are divided into two parts.
Cutaway showing the body plan of a snail. Mollusks have a true body cavity, a complete digestive system, and a circulatory system as well. (*Note the radula utilized by snails & slugs for feeding)
Phylum Arthropoda – Exoskeleton & Jointed Legs (“Arthro”=“joint”/ “poda”=“feet”) • Easily the largest phylum with somewhere around 1.2 million species • Have jointed appendages & a hard external skeleton called the exoskeleton (made of the polysaccharide chitin) • Includes insects, crayfish, lobsters, crabs, spiders barnacles, & ticks.
Insecta – largest class of arthropods • About a million insect species described so far • Many undergo metamorphosis: • Complete metamorphosis: the larval stages look very different from the adults (caterpillars – moths and butterflies and maggots – flies) • Incomplete metamorphosis: the young resemble the adults but are smaller with different body proportions
Phylum Echinodermata – “Spiny Skin” • All 7,000 species are marine • Include sea stars (the poster child of echinoderms), sand dollars, sea urchins, and sea cucumbers • Lack body segments; most are radially symmetrical • Can have hard spines or plates embedded under the skin which are actually part of the hard internal skeleton (endoskeleton) • Water vascular system – series of tubes & canals that branch into tube feet and are important in locomotion, feeding, and gas exchange.