Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Bellwork Plant or Animal? • What is an animal? • Backbone? Cell Wall? One Celled? Chapter 26 Sponges and Cnidarians What is an animal? • • • • • Heterotrophs Multicellular Eukaryotic Do not have cell walls Kingdom Animalia Invertebrates • Do not have a backbone or vertebral column • Size – from microscopic dust mite to giant squid (59 feet; almost a ton) • Include over 95% of all animal species Invertebrates • http://animals.nationalgeographic.com/anima ls/invertebrates/giant-squid/ Vertebrates • Represent the other 5 % • Have a backbone or vertebral column • Include fishes, amphibians, reptiles, birds, and mammals How Animals Survive • Feeding, respiration, circulation, excretion, response, movement, reproduction • Have many different ways to carry out these functions • Maintain homeostasis – temperature, blood sugar, heart rate, respiratory rate, etc…, • Feedback loops involve feedback inhibition – in which the product or result of a process stops or limits the process Feeding • Most do not absorb, but must eat or ingest it • Herbivores, Carnivores, Detritivores, Filter feeders, Symbiotic Relationships Respiration • Whether on land or in the water, all animals respire – take in Oxygen and give off Carbon dioxide • Some by diffusion • Some complex circulatory system organs and tissues • No Circulation • Some rely on diffusion to transport oxygen, nutrients, and waste products… Works because they are only a few cell layers thick • Larger animals rely on circulatory tissues, organs and systems to circulate oxygen, nutrients, and wastes Excretion • Ammonia primary waste product of metabolism that contains Nitrogen • Is poisonous • Must eliminate ammonia or change it to a less toxic substance to be removed from the body • Removing wastes maintains homeostasis Response • Responds to events in environment using nerve cells Sexual Reproduction • • • • By producing haploid gametes (egg and sperm.) Helps create genetic diversity Involves Crossing over Improves species abilities to evolve when the environment changes. Asexual Reproduction • Many invertebrates reproduce asexually • Offspring are genetically identical to parent • Increases numbers rapidly Complex Animals • Generally, the more complex, the more highly evolved • High levels of cell specialization • High levels of internal body organization • Bilateral symmetry • A front end or head with sense organs • A body cavity Bilateral Symmetry • Only one imaginary plane can divide the body into two equal halves. • They have left and right sides • Front and back ends- Anterior/Posterior • Upper and lower sidesDorsal/Ventral Cephalization • In animals with bilateral symmetry • Sense organs and nerve cells at the front end of the body • Respond to the environment more quickly and in more complex ways Radial Symmetry • Every animal has body symmetry except for sponges = Asymmetrical • Radial Symmetry – have body parts that repeat around the center of the body. Think of a bicycle tire in which any number of imaginary planes can be drawn through the center, each dividing the body into equal halves Sponges • • • • • • Sponges Simplest animals, least evolved 540 million years old Most ancient animals Most live in oceans From arctic regions to tropical waters Phylum – Porifera – meaning pore bearers Form and Function • No mouth or gut • No tissues or organ systems • A few specialized cells Body Plan • • • • Asymmetrical No front or back end Large cylindrical water pump Choanocytes – use flagella to move a steady current of water through the sponge • Water enters through pores and leaves through the osculum – large hole at top Sponges • Sponge with Dye • World of Sponges (Show at end of ppt.) • Freshwater Sponges (Show at end of ppt.) • This movement of water provides: feeding, respiration, circulation, and excretion • Have simple skeleton • Harder sponges – skeleton make of spicules – spikeshaped, made of chalk-like calcium carbonate or glasslike silica • Spicules made by archaeocytes – cells that move around within the walls of the sponge • Softer sponges have internal skeleton made of spongin – flexible protein fibers Feeding • Filter feeders • Digestion takes place inside cells • Food particles are trapped and engulfed by choanocytes Choanocytes (a summary) • • • • Have flagella Create current Trap and engulf food particles Transport partly digested food particles to archaeocytes Archaeocytes 1. 2. 3. 4. Make spicules Move around Complete digestion Transport digested particles Respiration, Circulation, Excretion • Carried out by moving water • Oxygen diffuses into cells • Carbon dioxide, and Ammonia diffuse out of the cells Response • No nervous system to respond to changes in the environment • For protection, some produce toxins that are unpalatable or poisonous • Spopnge Economy • Sponge Harvesting • 4 New Species of Sponges Reproduction • Sexually or Asexually • Most sponges form egg and sperm by meiosis • Eggs fertilized inside the sponges body – internal fertilization • Sperm of one sponge are released and carried by currents inside the body of another sponge • Archaeocytes carry the sperm to the egg • After fertilization, zygote develops into a larva • Larva are motile and carried by currents – until they attach to the sea floor and begin to grow Reproduction Asexual • By budding or producing gemmules • Budding – part of sponge breaks off, settles to the sea floor, and begins to grow • Gemmules – produced in difficult environmental conditions • Gemmules are groups of aechaeocytes surrounded by spicules The gemmules are another means of surviving adverse conditions, and germinate when conditions improves. They are composed of a mass of archaeocytes rich in food reserves, and in fresh-water species possess a hard coat. Marine gemmules develop external flagella at one pole and after swimming for a time attach by the opposite pole and develop into young sponges. • Gemmules can survive freezing temperatures and drought • When conditions become favorable, the gemmule will grow into a new sponge Ecology of Sponges • Provide habitats for snails, sea stars, and shrimps… Commensalism • Photosynthetic organisms provide food and oxygen for the sponge, sponge provides protection… Mutualism • In deep waters, spicules act like a lens, and focus sunlight to photosynthetic organisms – This adaptation allows sponges to live in a range of habitats Cnidarians Cnidarians • Phylum Cnidaria • Hydras, jellyfishes, sea anemones, and corals • Some live as individuals • Some live in colonies of dozens or thousands of connected individuals • Cnidarians • Cnidarians • Cnidarians are soft-bodied, carnivorous, and have stinging tentacles that surround the mouth • Have Radial symmetry and specialized tissues • Cnidocysts – stinging cells - along their tentacles – used for defense and catching prey • Cnidocysts have nematocysts – poison filled stinging structure that contains a tightly coiled dart p.669 • Nematocysts • Jellyfish • Box Jelly Form and Function • Specialized tissues for feeding and movement Body Plan • Have a life cycle that includes a polyp and medusa • Polyp – cylindrical, mouth points upward surrounded by tentacles, sessile • Medusa – motile, mouth on bottom, bell shaped body • Internal space – gastrovascular cavity – digestive chamber with only one opening a) Gastroderm – inner lining where digestion takes place b) Mesoglea –middle layer c) Epidermis – outer layer of cells Feeding • Paralyzes prey, pulls it through its mouth and into its gastrovascular cavity • Extracellular digestion • Absorbed by the gastroderm, where digestion is completed • Any materials that cannot be digested, exit the mouth Circulation, Respiration, and Excretion • Nutrients - transported by diffusion • Respiration – diffusion • Elimination - diffusion Response • Use specialized sensory cells –Nerve Net • Nerve Net – loosely organized network of cells that together allow cnidarians to detect stimuli – touch • Distributed uniformly • Statocysts – sensory cells that help determine the direction of gravity • Ocelli – eyespot – made of cells that detect light Statocyst = Gravity Movement • Different cnidarians move in different ways • Sea anemones – hydrostatic skeleton • Consists of a layer of circular muscles and a layer of longitudinal muscles that, together with the water in the gastrovascular cavity, enable the cnidarian to move • Body becomes taller • Muscles and Nerves • Medusa – jet propulsion – water comes in to and out of the bell Reproduction • Sexual and Asexual • Polyps – asexually – budding • Tiny Medusa – is produced asexually – budding – Large Medusa reproduces sexually Page 672 • External Fertilization – sexual reproduction • Most are either male or female • Sea Anemone vs Jellyfish • Lion's Mane Jelly Ecology of Corals • Distribution determined by a) Temperature b) Water depth c) Light intensity Symbiotic Relationship With Algae • Algae capture sunlight, recycle nutrients, and help corals lay down their Calcium carbonate skeletons. • Provide as much as 60% of the energy that corals need • This allows corals to live in nutrient poor waters Human Activity and Corals • Recreational divers break corals • Silt and sediments from logging, mining, and construction smother corals • Chemical fertilizers, insecticides, and industrial pollutants poison corals • Coral Bleaching – high water temperatures kill algae - which will lead to lack of oxygen and nutrients • circulatory system • pics cells