Bio 242 Week 7 Lecture Notes
Bio 242 Week 7 Lecture Notes BIOL 242
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This 6 page Class Notes was uploaded by LaKeisha Crum on Thursday October 6, 2016. The Class Notes belongs to BIOL 242 at University of Louisville taught by James Alexander in Fall 2016. Since its upload, it has received 33 views. For similar materials see Diversity of Life in Biology at University of Louisville.
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Date Created: 10/06/16
Bio 242 Notes Week 7 (Exam 2) A few videos that may help: Crash Course Annelids and Arthropods https://www.youtube.com/watch?v=YQb7Xq0enTI&index=23&list=PL3EED4C1D684D3ADF Phylum Annelida “segmented worms” or “rings” (worms that we’re used to are in this) Characteristics: Metamerism body parts repeated along body. (Called metameres). Each section is specialized. *This is important because it brought the idea of specialized parts.* each section of the worm is responsible for a different function. Osmoregulation: It is well developed in these animals. They have metanephridia. These are like flame cells in that they serve as the excretory system but they are different too. These are more advanced and are open at both ends. One opens to the outside (Like flame cells) and the other opens to the body cavity (unlike flame cells). These cells are large are filter waste out of the body cavity. TIP: If you can remember “m” then it will be easier to remember all of these words. There are a lot of terms starting with “m” (Metamerism, metameres, metanephridia) Triploblastic, eucoelomate, bilaterally symmetric, distinct head, and protostomes. Complete digestive system occurs extracellularly in lumen of gut. (Lumen basically means an opening) Close Circulatory System blood vessels and hearts. This is effective for rapid transport and gas exchange across body wall. *Exception leeches use an open system (blood found in bloodfilled sinuses) Well Developed Nervous System: brain and ventrally located nerve cord. In this system, the ganglia fuse to create rings that surround the esophagus. Many are predatory and some are herbivores and detritivores. Life Cycle: Many are monoecious (Vocab Review: one organism with body male and female reproductive parts). Primarily use sexual reproduction. Fertilization is external. Can occur two ways. Water column or cocoon. Larvae in marine called trochophores swim in plankton then settle to complete metamorphosis. Classes: Polychaeta (“chaete”=bristles) Free living scavengers and detritivores, mostly marine, many are dioecious (Vocab Review two organisms, each have separate sexes). Have parapodia: paddlelike structures. That help them move and breathe. TIP: Just associate the p’s. Parapodia and paddle. Oligochaeta (earthworms) Deposit feeders these feed on waste or debris. Monoecious but animals swap sperm to fertilize. Structure: epidermis (produces cuticle that keeps the worm from drying out. (TIP: works like our lungs. They breathe through their body wall so it must be kept wet. Just like our lungs) Setae two pairs per segment are extruded by retractor muscles and help the worm move. Clitellumproduce the cocoon TIP: To remember this group’s name, just look at the “O” and think obvious or ordinary. These are the ones that we know so they’re ordinary. Setae in Oligochaete vs. Polychaeta: Polychaeta have many pairs per segment. Oligochaetes: only have two pairs per segment. TIP: Oligo means few. Hirudinea (Leeches) Open circulatory system, no setae, several suckers (for attachment and movement), parasites, scavengers, or predators. Monoecious. TIP: You can remember this by also looking at the “H” in Hirudinea and thinking that leeches hurt. Phylum Mollusca Characteristics: 4 Body parts: head, foot, mantle, and shell. The foot is muscular with a visceral mass (this is a ball that holds the organs of the digestive and reproductive systems). Digestion: extracellularly in lumen of gut. Complete system. Have radula (ribbon of teeth of chitin). This is used to scrape food or to make holes in prey. Clams: use gills for filter feeding. TIP: To remember radula. Just think of radula as a rake. They sound similar and rakes scrape and can also make holes. Radula Triploblastic, eucoelomate, bilateral symmetry, distinct head, protostomes Metanephridia similar to that of annelids. Excrete NH3, osmoconformers (osmolarity of the organism’s cells is equal to pressure on the outside of their body. TIP: They conform to the osmolarity around them. Hence, osmoconformers.) Freshwater: excrete hypoosmotic (means that solution has a lesser concentration of solute. For example, water compared to salt water) urine. Terrestrial: convert ammonia to uric acid land snails (need less H2O to flush. They are not in water like others) Circulatory System: Open system: hemocoel is a part of this. This is a blood filled cavity. TIP: hemo usually relates to blood and we are used to the “coel” part in our body cavities. So just think blood body cavity. They also have hemoglobins (Vocab Review: these are pigments that help transport oxygen through the blood. We have these too) Respiration: They have gills but they also can get oxygen through their body wall. In pulmonate gastropods mantle forms a lung that lets them live on land. TIP: Once again “pulm” comes up. We can associate this with breathing and lungs. So these develop a lung to breathe. Nervous System: (Well developed and similar to the annelids) They have a brain and a ventrally located nerve cord. The nerves show unidirectional movement of action potentials. All of these advancements make them capable of more complex behaviors. Reproduction: Either monoecious or dioecious, internal or external fertilization. Marine molluscs have a trochophore. This is a top like larvae that swims around and then finally settles and completes metamorphosis. Immune System not completely developed but have amebocytes that protect against bacteria, fungi, protozoans, etc. The amebocytes engulf or surround invaders. Another line of defense is their skin (just like us). It acts like a barrier against foreign objects. Classes: Polyplacophora chitons (“poly” means many, so many plates) They have 8 plates that form a shell. Live in high energy environments (intertidal), have radulas to scrape algae off of rocks, large foot, and large mantle to hold on to the rocks. Gastropods (“stomachfoot”) snails and slugs. Coiled shell (but slugs do not have this), reduced foot, distinct head, radula, complete torsion. Torsion occurs when it flips its body 180 degrees above center of gravity to make movement easier. Also use mucus to move (slime snails and slugs leave behind) Have eyestalks with a pair of eyes on the end. (Remember: snails are the intermediate hosts for flatworms (flukes) Bivalvia (clams, oysters, and mussels) filter feeders, flattened shells with two valves (hence, bivalvia), gills, siphons (tubelike structures where water flows) Cephalopoda (squids, octopi, and nautilus) strong head, tentacles, suckers, external or internal shell, with or without radula, beaklike teeth, move with tentacles and jet propulsion. Close circulatory systems that help them move so quickly. Ecdysozoans: molting animals Phylum Nematoda very small. “nema”=thin, round worms Exhibit Eutely: all individuals have exactly the same number of cells and as development occurs, each cell is specialized. TIP: Eutely kind of looks like exactly, so just remember exact number of cells. Characteristics: Pseudocoelomates (no mesoderm in gut). They only have longitudal muscles in the gut wall (can only move one way can only flex body wall) Chitinous cuticlehas 4 distinct molts. Cuticle offers protection during these molts and hydrostatic pressure. Another word for molting ecdysis Can be temporary parasites, absorbing food in host’s digestive tract. (We’ve all heard of roundworms right?) Have a pharynx that helps them engulf food. Complete digestive tract (Hint: most of the phylums at this point have closed digestive tracts and extracellular digestion) No circulatory or respiratory systems (this is why they are so small) Have distinct male and females Internal fertilization. Male deposits sperm in the female with injection (wall of female is pierced and sperm then enters). Do not create a large number of sperm and egg because internal fertilization protects them. Osmoregulation do not flame cells but do have organs called renettes (canals) Phylum Arthropoda “joint foot” Characteristics: Spiral, determinate cleavage, segmentation, tagmatization (fused segments. Examples: head, thorax, abdomen) Jointed appendages each segment is called a podomere. Two types of appendages: Biramoustwo branches (crustaceans) or uniramousone branch Triploblastic, eucoelomate, bilateral, distinct brain, protostomes Extracellular digestion in lumen of gut, complete system Molt several times. Metamorphosis (“change in form”) Internal fertilization. Dioecious Respiratory: Book lungs in spiders’ abdomens. Layers of vents to allow breathing. Tracheae (insects) branched throughout body, near muscles and nerve cells (areas that need oxygen). Air diffuses into body but not straight to the lungs (like ours). Excretory: green glands, antennal glands, or Malpighian tubules. Antennal glands: (crustaceans) excrete ammonia, is a type of nephridium (tube that is open to the exterior and open at both ends). The terrestrial animals excrete uric acid (insects and spiders) for Malpighian tubes. These tubes are tubes that dump nitrogenous wastes and H2O into the gut. The Malpighian tube is nota nephridium bc it is closed at one end. TIP: To remember Malpighian tubes, just remember the word “pig” within. Pigs are terrestrial so they create uric acid and use these tubes. So you will remember that these tubules are only for terrestrial animals. Nervous System well developed with bran and paired ventral nerve cord. Circulatory: open. Hemolymph (blood) fills up hemocoel (Remember: this is a blood filled body cavity) They have a pumping heart. Classes: Cheliceriformes (fangs scorpions, spiders, mites, ticks, horseshoe crabs) 12 tagmata (Cephalothorax and abdomen), six appendages. Are small due to lack of developed resp. system, book lungs. Myriapoda (“many feet” centipedes and millipedes) distinct head with antenna, long segmented trunks Hexapoda (can also be called Insecta) 3 tagmata (head, thorax, abdomen), antenna, three pairs of legs, two pairs of wings, terrestrial, mandibles for chewing, gills or tracheae for respiration. Crustacea (Crabs, lobsters, crayfishes, and shrimp) antennae, 23 tagmata, chewing mouthparts (mandibles), <3 pairs of legs, marine and freshwater, legs and swimmers, exoskeleton made of calcium Phylum Echinodermat: sea stars, sea urchin, ophiuroidea, sea cucumbers Characteristics: All marine, radical cleavage, enterocoelous coelom, radial symmetry as adults, bilateral symmetry as larvae Dermal endoskeleton: made of plates called ossicles (bones). Water vascular system tube feet (hydrostatic pressure that move tube feet) Helps to distribute gases and waster through body and out. Breathe through external branchiae (fingerlike extensions off of the epidermis) Adults no brain, reduced nervous system Triploblastic, eucoelomate No segmentation, autotomy (intentional loss of body parts) regeneration of lost body parts. Extracellular digestion No excretory or circulatory systems. Reproductive: dioecious, external fertilization (shed gametes into open water)