Invertebrates Part 1 Animal Characteristics Sponges and Cnidarians April Adams Zoology

Zoology Standards SZ2. Students will explain the evolutionary history of animals over the geological history of Earth.   a. Outline the geological history of Earth and discuss the major environmental changes that have occurred over time. c. Describe the fossil record of the animals including discussing the Cambrian Explosion and major extinction events. SZ3. Students will compare form and function relationships within animal groups (clades) and across key taxa. a. Explain the similarities and differences among major body plans (e.g., asymmetry, radial and bilateral symmetry). SZ4. Students will assess how animals interact with their environment including key adaptations found within animal taxa.   a. Discuss morphological and physiological adaptations relative to ecological roles. b. Relate animal adaptations, including behaviors, to the ecological roles of animals. c. Explain various life cycles found among animals (e.g., polyp and medusa in cnidarians;

Characteristics of Animals 1. Multicellular, eukaryotes 2. Heterotrophs 3. Cells w/out cell walls, many have specialized functions 4. Usually have a method of movement 5. Most reproduce sexually 6. Require oxygen

Describe the Body Plans of Animals 1. Symmetry: balance in body proportions a. Asymmetrical:have irregularly shaped bodies, no symmetry

b. Radial symmetry: can be divided along any plane to produce 2 halves which look alike c. Bilateral: can be divided only one way to produce mirror image halves Radial Bilateral Symmetry Posterior end Dorsal Ventral Planes of Symmetry Anterior end Planes of symmetry

2. Body arrangements: a. anterior: head region b. posterior: tail region c. dorsal: back or top d. ventral: abdomen or bottom

Sponges: Phylum Porifera (“pore bearer”) Simplest of all animals Assymetrical animals that live in shallow waters Sessile filter-feeders whose bodies have many pores Obtain oxygen by filtering water No nervous system or organ systems No tissue organization Acoelomates

SPONGES Digestion: NO SYSTEM filter feeders / many pores .Choanocytes are flagellated cells that pull food in thru ostia (pores) and the amoebocyte cells circulate food around the organism Excretion: NO SYSTEM Basic diffusion; wastes exit thru osculum Circulation: None Respiration: NO SYS. diffusion-obtain oxygen from water Reproduction: sexual-Hermaphrodites(have sperm & egg)-Both sexes in same organism called monoecious: asexual- bud; Regenerate body parts

The Anatomy of a Sponge Outer epidermal layer Section 26-2 Water flow Osculum Central cavity Choanocyte Pores Spicule Pore cell Pore Epidermal cell Archaeocyte Outer epidermal layer jellylike middle layer ( amoeboid cells and spicules) Spongocoel- inner cavity lined with choanocytes

Sponge Body Structures A. Osculum: water exits-part of feeding B. Pore cells (ostia): water enters-part of feeding C. Collar cells:(choanocytes)- line interior, have flagella to filter out food from water D. Amoebocytes: carry nutrients from collar cells to body of the sponge E. Spicules- support/skeleton F. Epithelial cells-”skin”-support/protection

Simple Sponge Morphology Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Simple Sponge Morphology

Three Body Types(Forms) Asconoid- simple- pore cells open directly into sponge Syconoid- more complex- pore cells open into canals Leuconoid- most complex- pore cells open into canals that open into chamber (ex. Bath sponge)

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sponge Body Forms

Classes Calcarea- spicule made of calcium carbonate Hexactinellida- glass sponge (spicule-silicon) Demospongia- “people’s sponge”, spicules are spongin (ex. Bath)

Class Calcarea Grantia Small Vase shape Spicules of calcium carbonate Straight or 3-4 rays

Class Hexactinellida Euplectella Spicules Siliceous 6 rays

Class Demospongiae Spongia Spicules Siliceous spongin

Fig. 12.11a

Sponge Reproduction Asexually: Fragments break off and grow into new individuals Buds form from sides of parent sponge, break offnew spong can grow back missing parts (regeneration) Sexually: Hermaphrodites: produce both eggs and sperm Gametes are released into water (external fertilization)larva swim to new area

Lifestyle and Importance Aquatic- mostly marine sessile as adults with free living larva Importance- As filter feeders, they clean water in ecosystem Large sponges filter 1500 liters/day

Precambrian Before 670 MYA Porifera Platyhelmithes Mollusca Arthropoda Echinodermata Hemichordata Cnidaria Nemertea Annelida Lophophores Chordata Precambrian Before 670 MYA Protozoans

How much did your brain “sponge” in? What are the basic characteristics of Animals? What does the word Porifera mean? What type of structure? provide the skeleton of a sponge? Filter food out of the water? Allows water to exit the sponge? Class Hexactinellida has spicules made of? How do sponges survive without body systems? (Be specific)

Hypothesis of Multicellularity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hypothesis of Multicellularity

Cnidarians Phylum Cnidaria: “stinging cell” Hollow gut Marine animals with radial symmetry Germ Layers: 2 epidermal gastrodermal NO ORGAN SYSTEMS Segmentation: none Coelom: Acoelomate Movement: sessile or move Have tentacles- stinging cells found on tentacles Predators: capture and poison prey with stinging cells(cnidocysts) on tentacles called NEMATOCYSTS

One body opening (mouth) for food to enter and wastes to exit Structures: One body opening (mouth) for food to enter and wastes to exit Gastrovascular cavity: interior cavity where food is digested & nutrients are circulated around the body Nerve net: net of nerves that allow impulses to travel around the body, senses the environment Label the hydra on your notes!

Without Body Systems, how do they survive? Nervous: Cephalization absent; Nerve Net-conducts impulses Skeleton: Hydrostatic- water pressure maintains shape Respiration: Oxygen diffuses into body from water Digestion: one body opening for food & wastes Excretion: Circulation: none Respiration: oxygen diffuses into body from water Reproduction: asexual and sexual, alternation of generations

Cnidarian Reproduction Asexually reproduce by budding Sexually reproduce in medusa form only, sperm and eggs are released into water (fertilized egg zygotelarvaadult) Thousands of gametes are released at a time

Alternation of Generations:

In the box on your notes answer the following: Explain why sponges and cnidarians release so many gametes into the water

Cnidarians: Body Forms Polyp: body with tentacles hanging upward Ex: hydra, sea anemone Medusa: body with tentacles hanging downward Ex: jellyfish

Structure:The Polyp and Medusa Stages Epidermis Mesoglea Gastroderm Tentacles Mouth/anus Gastrovascular cavity Mesoglea Gastrovascular cavity Mouth/anus Tentacles Medusa Polyp basal disc: sticky structure at the bottom of polyp ; sessile

Groups & Uses of Cnidarians 3 Groups of Cnidarians: 1. Hydrozoans: colonies which appear to be one organism Ex: Hydra, polyp, Portuguese-man-of-war, 2. Scyphozoans: independent medusa forms Ex: jellyfish, box jelly, medusa 3. Anthozoans: colonies of polyps Ex: corals, sea anemone Riches of the sea