Exam 3 Study Guide, Bio210B

Exam 3 study guide Chapter 32, 47 What characteristics do organisms in the animal kingdom share? Heterotrophs that ingest their food Multicellular eukaryotes Cells lack cell walls Some have nervous tissue and muscle tissue Most animals reproduce sexually Describe the stages of embryonic development: cleavage, blastula, gastrula After a sperm fertilizes an egg, the zygote undergoes rapid cell division called cleavage Cleavage leads to formation of a blastula (blastocyst in mammals) The blastula develops into a gastrula with three layers of embryonic tissues (germ layers) What are the three germ layers in an early embryo? Ectoderm (outer layer of skin, hair, lining of the nose and mouth) Endoderm (digestive tract, respiratory tract, liver) Mesoderm (muscles and skeleton) How do the ZPA and SHH control limb development? How is limb development affected if an additional ZPA is transplanted to the top of the limb bud? Zone of polarizing activity= tissue on the limb bud of embryo, controls limb development. ZPA secretes a protein signal called SHH. Concentration of SHH determines digit development. High concentration = pinky; low = thumb. Two sets of digits is developed (mirrored) when ZPA is transplanted to the top. Five key innovations in animal evolution: Tissues (specialized organized cells; all animals but sponges) Radial vs bilateral symmetry (except sponge; radial showed up first, no head) Body cavity (coelom): fluid filled space between digestive tract and body wall, supports organs, distributes materials coelomate (“true” body cavity, mesoderm lines entire body cavity like in humans) acoelomate (no body cavity) pseudocoelomate (false body cavity, not completely lined with mesoderm) Humans have a body cavity, flatworms do not. Segmentation: division of body into repeated segments Ex: worms; (cervical, thoracic, lumbar, pelvic) Embryonic Development: (blastopore and radial vs. spiral cleavage) Protostome (mouth forms from blastopore, spiral cleavage) Deuterostome (anus forms from blastopore, radial cleavage) Most animals are protostomes, chordates and echinoderms are deuterostomes Chapter 33 General characteristics for all animal phyla: know symmetry, # of germ layers (diploblastic, triploblastic), protostome or deuterostome, segmentation, type of digestive system (none, gastrovascular cavity/incomplete digestive system, complete digestive system), and additional characteristics discussed in class such as reproduction and feeding All the following are invertebrates (account for 95% of known animal species) Gastrovascular cavity = aka “incomplete” digestive system with one opening Porifera (sponges): Lack true tissues, organs, symmetry Sessile filter-feeders, mostly marine Both sexual and asexual reproduction Spicules (needle like structures for support + defense) What is a choanocyte? Collar cell, flagellated found within sponges, creates water flow Cnidaria (jellies, corals); First animals with movement, diploblastic but no organs, nerve net, gastrovascular cavity, radial symmetry Medusa (floating) vs polyp (sessile) stages; function of cnidocytes (stinging cells)/ nematocysts (organelle that ejects stinging threads) Describe the life cycle of a hydrozoa (obelia) Colony of polyps formed through asexual budding Reproductive polyps make medusa (asexual) Medusa make gametes fertilize and make larva (planula) Planula larva grows into new polyp Distinguish between the three classes: Hydrozoa (dominant polyp stage, polyps can form into colonies) Scyphozoa (true jellies, dominant medusa stage, gonads- 4 clover) Anthozoa (Corals and sea anemones, ONLY polps) Ctenophora (comb jellies): 8 rows of combs to swim Platyhelminthes (flat worms): Marine, water, oxygen, nutrient transport via diffusion, triploblastic, gastrovascular cavity, acoelomate Significance of cephalization? (nervous and sensory tissues become concentrated in head making “brain”, coordinates and controls sensory information and nervous activity) Describe the life cycles of trematodes (blood fluke) Eggs passed in feces Hatch and become free-swimming ciliated larva (miracidium) Parasite develops in snail host Becomes motile larva Larva penetrates skin, human host Nematoda (round worms): First animals with complete digestive system, pseudocoelom, aquatic habitats, soil, body fluids and tissues of animals Examples of important nematodes: C. elegans: Model organism in research, ability to regenerate nerve cells Ascaris: trichinella spiralis, acquired by humans from undercooked pork Hookworm: sucks blood in small intestine Rotifera (rotifers): general structure. Crown of cilia around mouth, jaws, stomach, anus Why is this an animal, despite being smaller than protists? Multicellular, have body cavity, specialized organ systems, complete digestive tract (mouth and anus) Annelida (segmented worms): body composed of a series of fused rings, complete digestive system, ex: leeches and earthworms Why is segmentation beneficial? (efficient movement, repeated organs in segments) Mollusca (snails, octopi): Describe the general body plan of a mollusk, and discuss how this has been adapted in the different classes. How are they adapted to their environment? Soft bodied but most are protected by a hard calcium carbonate shell, 3 main parts, muscular foot, visceral mass (internal organs), mantle. Benefit of shell = protection; no shell = movement Distinguish between these classes: Polyplacophora: encased in eight plates, use foot like suction cup to grip rock Gastropoda: ¾ of molluscs (snails and slugs) Cephalopoda: carnivores with beak-like jaws surrounded by tentacles (modified foot), immobilize prey with a poison present in their saliva, intelligent. big head, lots of feet, ex: octopus cuttlefish Bivalvia: shell divided into two halfs ex clams, oysters, mussels, scallops (up to 100 eyes) Molluscs are the animal group with the largest number of recent extinctions because of habitat loss, pollution, and non-native species Arthropoda (crustaceans, insects): Largest animal group, 80% Discuss the general body plan, and adaptations seen in arthropods Segmentation = head, thorax, abdomen. Jointed appendages modified for functions (walking, feeding, defense, etc). Covered by exoskeleton of chitin Pros/cons and structure of the exoskeleton Pros = protection and defense Cons = vulnerable without, energy consumption of creating new exoskeleton is 2 high Why are arthropods so successful? Exoskeleton, diversification of segmentation, diversification of appendages, advanced sensory system (eyes and antennae), found in all habitats of the biosphere Distinguish between four major subphyla: Chelicerata: clawlike feeding appendages = chelicerae ex: spiders, scorpions, tick Myriapoda: many feet, ex millipedes (eat decaying leaves and plant matter) centipedes (carnivores) use poison claws to paralyze prey Hexapoda: all insects, six legs, most abundant eukaryotes on earth, flight is one key to their great success. Incomplete metamorphosis: young resemble adults but smaller. Complete metamorphosis: larval stages look different from adult shap. Beneficial as pollinators Crustacea: live in marine and freshwater environments, ex:mantis shrimp, decapods (lobsters, crabs) Echinodermata (sea stars, sea urchins): ONLY INVERTEVRATES WITH DEUTROSTOME DEVELOPMENT, slow moving or sessile marine animals. Thin epidermis covers an endoskeleton of hard calcium carbonate plates. Larva = bilateral symmetry, adult = radial. Most reproduce sexually but asexual regeneration is also common Distinguish between four classes: Asteriodea: Sea stars which feed on bivalves and hunt/move to get their food Ophiuroidea: brittle stars distinct round central disk and long flexible arms Echinoidea: sea urchins (feed on seaweed using jaw like structure, aristotles lantern) and sand dollars, spines used for locomotion and protection Holothuroidea: sea cucumbers, lack spines, reduced endoskeleton, five rows of tube feet Describe the function of the water vascular system (locomotion and feeding) H2O enters through madreporite (hole on top) then goes into bulbs (ampullae) in arms. Ampullae contract -> h2o into tube feet equals movement Chapter 34 Four characteristics of chordates. What is their function? What do they develop into in an adult mammal? Bilateral, segmented animals, deuterstome development All chordates at some point in development have notochord: flexible rod, becomes part of vertebral column; dorsal nerve cord: tube for nerves becomes central nervous system; pharyngeal gill slits: for respiration and feeding, become jaw and ears; post-anal tail Lancelet and tunicates: how are these different from the other chordates? Invertebrates In which classes do we first find: vertebrae, jaws, bony skeleton, four limbs, amniotic egg, milk? Class mammalia Agnatha: general characteristics Jawless fish, lacks scales and well-developed vertebrae ex: hagfish and lampreys Chondrichthyes (cartilaginous fish): general characteristics Jaws, cartilaginous fish, ex: sharks, rays, skates how did jaws develop? From pharyngeal gills Osteichthyes: general characteristics Bony endoskeleton ray-finned and lobe-finned, breathe by drawing water over gills Oviparous egg outside; viviparous outside us; ovoviparous eggs inside which group of bony fish is the closest relative to tetrapods? LUNGFISH Transitional stages between fish and tetrapods: Tiktaalik (what features does it have of both groups?) fish characteristics = scales, fins, gills and lungs; tetrapod= neck, ribs, fin skeleton, flat skull, eyes on top of skull Adaptations found in tetrapods Four limbs and feet with digits; neck, absence of gills, ears for detecting airborne sounds Amphibia: general characteristics Breathe through skin (gas exchange) ex: salamanders, frogs Why are they still tied to water? For reproduction and early developemtn Reptilia: general characteristics What is an amniotic egg and how is it beneficial? Contains membranes that protect the embryo, key adaptation to life on land Ectothermic (external heat as main source of body heat) vs endothermic? Aves: general characteristics What adaptations allow for flight? Wings with feathers, light bones, strong flight muscles attached to breastbone, teeth, acute vision What dinosaur group did birds evolve from? therapods Mammalia What characteristics do all mammals share? Hair, mammary glands, high metabolic rate, differentiated teeth Three groups of mammals: monotremes, marsupials, eutherians/placentals Characteristics of primates How are the jaw bonds and middle ear bones different in mammals (stapes, incus,malleus) and reptiles (stapes)? Traits of modern humans Early hominins: how do we know they had increasing bipedalism? Other characteristics? Australopiths: Characteristics? How were they similar to modern humans, and to chimps? Genus Homo: Why did brain size increase? Homo habilis Homo ergaster: significance of decreased sexual dimorphism? Homo erectus: benefit of lack of body hair? Homo heidelbergensis Homo neanderthalensis: How were they different from Homo sapiens? Homo sapiens What are “mismatch diseases”?