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Characteristics of Animals + Sponges & Cnidarians Chapter 23A

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1 Characteristics of Animals + Sponges & Cnidarians Chapter 23A
Honors Biology & Chapter 30 Biology Jenkins

2 What is an ANIMAL? 1. Multicellular, eukaryotes 2. Heterotrophs 3. No cell walls, many have specialized functions 4. Usually have a method of movement 5. Most reproduce sexually 6. Requires oxygen

3 GROUPS Vertebrates = have a backbone - 5% 2. Invertebrates = have no backbone 95% WHY THE BIG DIFFERENCE?

4 Survival Needs Feeding Respiration Circulation Excretion Response
Movement Reproduction

5 All animals: Feed: carnivores, herbivores, omnivores, detritivores (eat/decompose dead materials), filterfeeders, predator, prey, symbiotic relationships (parasite/host) Respiration: take in oxygen give off carbon dioxide Circulation: diffusion or system Excretion: release ammonia and other waste products Response: nerve cells that respond to stimuli Movement: ability to move parts or move around Reproduce: sexually (egg & sperm) or asexually (budding)

6 Describe the Body Plans of Animals
1. Symmetry: balance in body proportions 2. Asymmetrical:have irregularly shaped bodies, no symmetry

7 Spherical Symmetry = globe or ball shaped Ex. Volvox

8 3. Radial symmetry: can be divided along any
3. Radial symmetry: can be divided along any plane to produce 2 halves which look alike (like a pie or bicycle wheel) 4. Bilateral: can be divided only one way to produce mirror image halves Posterior end Bilateral Symmetry Radial Symmetry Dorsal side Anterior end Ventral side Plane of symmetry Planes of symmetry

9 Asymmetry Irregular Body Shape Often sessile organisms Ex. sponges

10 Radial Symmetry Can be divided along any plane, into roughly equal halves. Ex. Sea Star

11 Bilateral Symmetry Can be divided into similar left and right halves that form mirror images of each other.

12 5. TERMS OF DIRECTION: a. anterior: head region b. posterior: tail region c. dorsal: back or top d. ventral: abdomen or bottom Dorsal Anterior Posterior Ventral

13 Trends in Evolution Complex animals have high level of cell specialization, internal structures, front end/head with sensory organs and a body cavity Cell Specialization = separate roles for each type of cell in multicellular organisms

14 Cephalization Animals with cephalization, have the brain and their sense organs toward the front / anterior aspect of the body Allows them to respond quicker

15 Body Cavity Formation Most animals have a body cavity (fluid filled space between digestive tract and wall) Important because organs can be suspended in there Some cavities contain fluid involved in circulation, feeding and excretion

16 2. Early states of development -cells divide to produce a hollow ball of cells called blastula.
SKETCH – From Overhead

17 Animal Development Most develop from a single fertilized egg called a zygote. 2 Stages of development Blastula- single layer of cells around a fluid-filled space. Gastrula- structure made of two cell layers

18 Blastula Development

19 Gastrula Development

20 Protostome and Deuterostomes
See page 661 in Dragonfly textbook and sketch it!

21 Protostome vs Deuterstome
Protostome: (from the Greek: first the mouth) An animal whose mouth is formed from the blastopore (opening in the gastrula) Most invertebrates Deuterostome: (from the Greek: "second mouth" ) An animal whose anus is formed from the blastopore, mouth formed second Ex. Echinoderms and all vertebrates

22 Animation of Protostome & Deuterostome Development
Protostome and Deuterostome Development

23 ENDODERM = innermost germ layer
Becomes: lining of digestive tract and much of respiratory system ECTODERM = outermost germ layer Becomes: sense organs, nerve and outer layer of skin MESODERM = middle germ layer Becomes: muscles, circulatory system, reproductive and excretory systems

24 Sponges Phylum: Porifera

25 Sponges – Introduction
Simplest, oldest animal type Evolved about 540 million years ago (mya) Found in oceans everywhere, and some in freshwater Phylum Porifera = “pore bearing”

26 Characteristics of Sponges
Multicellular, eukaryotic, sessile (not moving) heterotrophic filter feeders, no cell wall, few specialized cells, Asymmetrical, look like large, cylindrical water pump. 2 cell layers thick Choanocytes (collar cells)- move water through the pore cells into the body cavity and out the osculum Simple skeleton made of spicules Archaeocytes (cells that move through the sponge distributing food and making spicules)

27 Figure 26–8 The Anatomy of a Sponge
Section 26-2 See handout given out in class

28 Feeding in Sponges Water flow provides for feeding, respiration, circulation and excretion. Sponges filter feed. Choanocytes trap food particles as water circulates. Food is digested intracellularly. Archaeocytes distribute food to other cells.

29 Sponge Animation

30 Respiration, Excretion & Circulation in Sponges
Water circulates through sponge. Oxygen diffuses out of the water, into cells. Carbon dioxide leaves the cells and enters the water. Sponges rid wastes by letting it diffuse out. Sponges rely on water movement to circulate what they need.

31 What about a Nervous System?
Sponges do NOT have one! Some can make toxins for keeping predators away!

32 Reproduction- sexual or asexual, most are hermaphrodites (produce both egg & sperm at different times) Sexual- sperm from one sponge are carried to another sponge for internal fertilization. Larva (immature stage that looks different from the adult) is released and swims away. (Advantage?) Asexual- budding or gemmules (a group of archaeocytes surrounded by spicules- can survive harsh conditions until ready to grow

33 Ecology of Sponges Large sponges – provide habitat for marine invertebrates (IE: shrimp, sea stars, snails) Some live in symbiosis with Bacteria, Algae and Protists. ? Why are some sponges Green?


35 CHARACTERISTICS 1. Soft-bodied 2. Carnivores
3. Have stinging tentacles arranged in circles around mouth Used for defense and to capture prey 4. Marine (A few Freshwater) 5. Invertebrate 6. Radial Symmetry 7. Simple Nervous system

36 Nematocysts Are poison filled stinging structures.
Used for defense and to capture prey.

37 Two Body Forms Polyp Vase-shaped body Medusa Bell-shaped body

38 Other Structures Nerve net-allows for detection of stimuli.
Ocelli (eyespots)- detect light Hydrostatic skeleton- enhances movement. Gastrovascular cavityinterior cavity where food is digested & nutrients are circulated around the body

39 Reproduction Asexual- budding Sexual- external fertilization in water

40 Class Scyphozoa Medusa Stage Ex. jellyfish

41 Class Hydrozoa Polyp/Medusa Form Ex. Portuguese-Man-Of-War Ex. Hydra

42 Class Anthozoa Polyp Stage Destroyed by human activity
Ex. Sea Anenome and Coral

43 Cnidarian Life Cycle

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