BIO- Invertebrates - Lecture notes 32-34 PDF

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Phylum Porifera (Sponges)         

Sponges No tissues, no symmetry Sponges are most likely to feed on diatoms (all single cell prostists) They have no tissues, no gastro vascular cavity Adults sponged are benthic, sessile, filter eaters (suspension) Multicellular, loosely organized cells which does not create a tissue Can reproduce asexually or sexually Chanocytes move the food through the cell Amoebacytes capture the food

Phylum Cnidara (jelly fish)                

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Diploblastic: only 2 embryonic germ layers Corals Nerve cells that aren’t present in sponges No true muscles, they have muscle fibers. They do not have a mesoderm Gas exchange through simple diffusion Has a gastro vascular cavity for extracellular digestion—sponges have a intracellular digestion No anus, their mouth is also their anus Cnidaria have 2 layer of tissues compared to bilateral animals Some cnidaria are sessile but not all. But also some bilateral animals are sissile as well The nematocysts(stinging cells) come from a cnidocyte cell in a cnidarian (hence the name), They release toxins to catch prey and defense Not all cnidaria have nematocysts They are mostly marine predators Two types: medusa and the polyp Polyp are sessile, do not move around. Medusas move with the current and are poor swimmers 4 clades: Hydrozoans, sycphozoans, anthozoans, cubazoa Hydrozoans o They alternate between polyp and medusa  The medusa are typically small Sycphozoans o Dominant medusa Anthozoans o Dominant polyp Cnidarians can reproduce sexually and asexually

Bilateria  

Skin comes out of the ectoderm, muscles are from the mesoderm and the digestive lining Locophopore have a trochophore or a lophophore o They are protostomes

Phylum Patyhlminthes: Flatworms         

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Bilateral symmetrical with a head Among first animals with active predatory lifestyle Lack fluid-filled cavity Digest food in gastro vascular cavity, then eject undigested material through mouth Eye spots, protonephridia, reproductive Platyhelminthes are flat because they have no need for respiratory/circulatory Can reproduce sexually and asexually Cephalization( a head) allows for a more predatory life style Ways to increase surface area: branching, flattening, folding, being small, projection o Parasites  Flukes(termatoda)  Tape worms  They are constantly attached to their host or access to nutrients so no need for gastro vascular cavity Over 100,000 species Muscular foot functions in locomotion, anchoring, tentacles Visceral mass Mantle secretes shell for protection or is modified for locomotion

Phylum Mollusks     

have organ systems Complex nervous system Circulatory system: heart and gills Metanephridia Most molluscs have an open circulatory system, Because they are less active they have an open circulatory system that does not transport oxygen well. A closed circulatory system does o Gastropods  Snails and slugs  ¾ of all living species of mollusks  Radula: scrape algae or bore holes in prey  Can have a conical shell, coiled shell, or no shell  They secrete their shells and as they get bigger they add to their shells o Bivalves  Are filter feeders with a reduced head  Gills are used for feeding as well as gas exchange  Quite sessile o Cephalapods  Are fast predators mostly with shell reduced or absent  Squids, octopus

Phylum Annelida o o

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Segmented worms, their bodies are made of multiple segments Advantages 1) Reputation of components provides backup 2) More flexible in how coelom can be used as hydrostatic skeleton 3) Allows specialization Have a closed circulatory system  Carries organic molecules, waste They have a complete digestive tract, an anus and a mouth Many annelids have appendages that help in locomotion Two main clades: Errantia and Sedentaria (organized by movement)  Sendentaria have setae or non and are more sedentary  Includes earth worms, tube worms, and leeches  All sendentarias are detritivores

Chapter 33: Ecdysozoa and Deuterostomia  

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Ecdysozoans molt, the exto-skeleton does not grow with the animal Posses a tough cuticle for support and protection o Separate from Lophotrochozoa o 8 phyla- 2 considered o Ecdysozoans molt, the exto-skeleton does not grow with the animal Phylum Nematoda o In nearly all habitats from poles to tropics o Free living and parasitic o Over 20,000 known species o They have a tough collagen cuticle that covers the body that they need to shed o They have a pseudocoelom  Acts as hydrostatic skeleton and circulatory system o They do have muscles, but they are longitudinal  They move by undulations o Complete digestive tract o Produce sexually, females can have 1000 zygotes a day o They are not acoelomates o Almost every species has a nematode for that species Phylum Arthropoda o Most successful animal phylum o ¾ --------------------------------o Are segmented and have specialized appendages  Appendages for locomotion, food handling, reproducation  Tagmata- fused body segment  Have flexible body plan that allows them to live in all biomes o Have a exoskeleton made of chitin  Can be extremely tough, soft, or flexible

Developed brain organs for sight touch smell Complete digestive tract Open circulatory system Gas exchange- gills, tracheal system with spiracles or book lungs (crayfish)  Gills in aquatic  Tracheal system in terrestrial arthropods (grass hoppers)  Spiders have book lungs Chilicerates o Spiders scorpions ticks and mites  2 tagmata- cephalothoraz and abdomen  4 pairs of walking legs, pedipalps, and chelicerae Crustaceans o Crabs lobster barnacle shrimps and coprpods o Marine fresh water and terrestrial o Fused chephalothorax o Unique 2 pairs of antennae Hexapods: insects o More species of in insects o 6 legs o Winged Deuterostomia: Echinodemata and Chordata  Blastospore delvlops anus  _______ __________ o Echinoderm do not have bilateral symmetry in adults o Spiny skin o Have modified radial symmetry  Adults: radial symmetry often 5 part  Evolved from an ancestral bilateral symmetry  Larvae are bilateral o They have no chepuli  No brain o Complete digestive tract o Water vascular system is a unique feature of echinoderms  Derived from coelom  Extends into tube feet  Function in movement, gas exchange and feeding  5 main clades- all strictly marine o Asterodiea: Sea stars   o Ophiuroidea:Brittle stars  Distinct central disk and long flexible arms o o o o

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 Tube feets not involved in locomotion Sea urchins and sand dollars Holothroidea: Sea cucumbers  Lack spines  Endo skeleton is reduced  Elongated  Have unusual defenses

Chapter 34 Phylum Chordata 

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All chordates exhibit 4 characters o Notochord-single flexible rods o 2 dorsal hollow nerve cords o Pharyngeal slits o Post anal and tail Sub phylum Cephalochordata- Lancelets o 26 species all marine filter feeder o Gas exchanges across body surface o Usually sessile but can burrow and swim Subphylum Chordata Urochordata – Tunicates o 3000 marine species o Larvae are tadpole like and exhibit all 4 chordate traits o Adults look very different but have post-anal tail

Vertebrates have all the Chordata characters plus    

Cartilage or bone Endoskeleton of cartilage or bone Cranium Complex internal organs livers kidneys endocrine gland and a heart with at least two chambers

Hagfishes     

Notochord Cartilagous skull Important deep sea scavengers No jaw, finless, marine fishes,and highly reduced vertebrae Produces copious amounts of slime

Lampreys 

Lack hinged jawa and paired fins

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Posses a notochord and rudimentary bertebral column Many lampreys are parasitic as adults Oral disk and rasping tongue covered with tooth-like keratin plates

Gnathosotomes- jawed organisms   

Jawless fishes are agnathans or ( Gnathostomes are jawed vertebrates Jaws mostly evolved from gill arches

Class Chondrichthyes (sharks)       

Sharks, skates, rays, chimareas Skeleton made of flexible cartialage o Derived character not ancestral chacter Among earliest fish to develop teeth o Not set into jaw Do not have swim bladder o Must swim to maintain buoyancy (most cartilaginous fishes) Sharks are powerful swimmers o Like all fishes, they have a 2-chambered heart with single circulation Have lateral line like all fishes o Sense waves of pressure Produce by internal fertilization; 3 strategies o Oviparous-lay eggs o Ovoviviparous-egg retained in female, no placenta o Viviparous- eggs develop uterus, placenta, nourishes young

Bony fishes (ostep 

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3 main features that separates the from chordrichthyes o Bones skeleton o Operculum covers gills o Swim bladder for buoyancy 2 major groups  Look at pectoral fins o Ray- finned fishes  Fins supported by thin…..  ……. o Lobe-finned fishes- coelacanths and lungfishes  Fins supported by extension of skeleton  Gave rise to tetrapod  Amphibians belong in this clade  Coelacanth: 2 living species  Lungfishes: 3 genera with 6 species o Live in oxygen poor freshwater: both girlls and lungs

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In most species gills atrophied- fish must breathe air Lungs are homologous to tetrapod

Tetrapods o Have four limbs with digits o Share a common ancestor….. o Tetrapods transitioned to land  Amphibians and Amniotes o Their adaptations to support their bodies outside of water  Strong bones  Ribs o Locomotion  Four limbs with digits  Neck… o Adaptations to prevent desiccation  Amniotes: waterproof scales and skin  Amphibians: behavioral and in some) semipermeable membrane on skin o Tetrapods have adaptations for gas exchange in air  Amphibians do not have interal ingestiation’ o Class Amphibia  Frogs salamanders, Caecilians o Amphibians gave several strategies for gas exchange  Bucal pumping  Skin absorbs oxygen  Some have gills throughout life o Amphibians have a 3-chambered heart  Higher pressure to tissues than single circulation  Mixing blood in single ventricle o Amphibians live in close association with water  Aquatic larval stages  Adults spend time out of the water but must return to breed o Amphibians as indicators o Many frogs are declining worldwide  Several causes  Disease causing fungus  Pollution  Parasites  Habitat loss  Climate change AMNIOTES (Reptiles and mammals) o Names after the ebryonic egg o Shelled egg: shelters the embryo from desiccitaing conditions on lands  Broke tie to water o Desiccation resistant

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Thoracic breathing- negative pressure sucks air in Water-conserving kidneys- concentration waste prior to elimination Internal fertilization  Allows for egg shell or retention of embryo inside female reproductive tract 5 extant classes  Reptile classes  Turtles  Lepidosaurs (snake)  Crocodilians  Birds  Class Mammalian Turtles  Have a protective shell  Vertebrae and ribs fused to shell  Terrestrial, freshwater and marine  Temperature of egg incubation determines sex Leidosaurs  4,800 species lizards, 3000 species snakes, 2 speices  Squamates  Many are omnivores  Some are predators with various adaptation to hunting  Toxins  Loose jawbones  Terrestrial, freshwater, and marine environments  Have a 3 chambered heart Crocodilians  4- chambered hearts  Upturn nostrils helps breathe air while shallow water Birds  Only extant group of reptiles descended directly from dinosaurs  Adaptations that aid in birds flight  Feathers  Hollow bones  Respiratory system with air sacs  Reduction of organs  Unique characteristics help with flying  1) Air Sacs 2) reduction of organs, eg. One ovary  3) lightweight skeleton- thin, hollow, honeycombed  4) Feathers- modified scales keep birds warm and enable flight  The birds and mammals are homeotherms  Birds are endotherms  Non-bird reptiles are ectotherms (internal temperature matches the temperature of the environment)

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 Flight and endothermy require higher metabolism  Birds have double circuo=lation with a 4 chambere heart  Most birds brood egges. And many have complex behaviors and vocalizations Class Mammalia o Evolved from amniote ancestors o Flourished after dinosaur extinction o Over 5000 species o Huge ranges of size o Have mammary glands that secrete milk o All mammals have some hair o Mammals have specialized teeth o Mammals have a large brain and skull  Single lower jaw bone  External ears  3 inner ear bones o Are endotherms with subdermal fat stores  High metabolism, four chambered heart o 3 clades of mammals  Monotremes  Marsupial  Eutherians o Monotremes: Platypus and echidnas  Lay eggs o Marsupials  Young finish development in marsupium o Eutherians: Placental mammals  Young complete their embryonic development within uterus, joined to the mother by the placenta  Long lived, complex placentas  Prolonged gestation  Are a diverse group with 18 extant groups o Primates  Lemurs, tarsiers, monkeys and apes  Grasping hangs with opposable thumbs  Primates have a large brain and binocular vision  Have complex social behavior nd well developed parental care  Apes do not have tails and monkeys do  Most monkeys have tails and are typically smaller  Apes don’t have tails  Usuauly larger than monkeys  Brachiation  Gibbons, gorillas  Humans are most closely related to chimpanzees  Bipedalism= walking on two legs

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Humans evolution  ^ mya, hominin split from other primates  Evolution not a neat progression: 1 or 2 specieces coexsiting at the same time  Key characteristic was bipedalism  Australopiths o Early himinins o Widespread several spiecies  Homo o Increased brain size o UPRIGHT man o Stone Tools o Oldest human with modern human proportions o Longer legs and shorter arms o Migrated out of Africa o Neatherthalensis shares common ancestor with modern humans  Larger brain, stocker build  Originated Europe ...