Characteristics of Animals + Sponges & Cnidarians

Chapter 23AHonors Biology

& Chapter 30 Biology

Jenkins

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

GROUPS

1. Vertebrates = have a backbone

- 5%

2. Invertebrates = have no backbone

- 95%

WHY THE BIG DIFFERENCE?

Survival Needs

• Feeding• Respiration• Circulation• Excretion• Response• Movement• Reproduction

• 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)

Describe the Body Plans of Animals

1. Symmetry: balance in body proportions

2. Asymmetrical:have irregularly shaped bodies, no symmetry

Spherical Symmetry = globe or ball shaped

Ex. Volvox

Dorsal side

Posterior end

Anterior end

Ventral side

Plane ofsymmetry

Radial SymmetryBilateral Symmetry

Planes ofsymmetry

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

Asymmetry

• Irregular Body Shape

• Often sessile organisms

• Ex. sponges

Radial Symmetry

• Can be divided along any plane, into roughly equal halves.

• Ex. Sea Star

Bilateral Symmetry

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

5. TERMS OF DIRECTION:

a. anterior: head regionb. posterior: tail regionc. dorsal: back or topd. ventral: abdomen or bottom

Dorsal

Ventral

AnteriorPosterior

Trends in Evolution• Complex animals have high

level of cell specialization, internal structures, front end/head with sensory organs and a body cavity

1. Cell Specialization = separate roles for each type of cell in multicellular organisms

Cephalization

• Animals with cephalization, have the brain and their sense organs toward the front / anterior aspect of the body

• Allows them to respond quicker

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

2. Early states of development -cells divide to produce a hollow ball of cells called blastula.

• SKETCH – From Overhead

Animal Development

• Most develop from a single fertilized egg called a zygote.

• 2 Stages of developmentBlastula- single layer of cells around a fluid-filled space.Gastrula- structure made of two cell layers

Blastula Development

Gastrula Development

Protostome and Deuterostomes

• See page 661 in Dragonfly textbook and sketch it!

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

Animation of Protostome & Deuterostome Development

• http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it+swf::550::400::/sites/dl/free/0078695104/383922/ch24.swf::Visualizing Protostome and Deuterostome Development

ENDODERM = innermost germ layer• Becomes: lining of digestive tract and

much of respiratory systemECTODERM = outermost germ layer• Becomes: sense organs, nerve and

outer layer of skinMESODERM = middle germ layer• Becomes: muscles, circulatory system,

reproductive and excretory systems

SpongesPhylum: Porifera

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”

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)

Section 26-2

Figure 26–8 The Anatomy of a Sponge

See handout given out in class

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.

Sponge Animation

• http://glencoe.mcgraw-hill.com/sites/0078695104/student_view0/unit7/chapter24/concepts_in_motion.html#

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.

What about a Nervous System?

• Sponges do NOT have one!

• Some can make toxins for keeping predators away!

• 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

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?

CNIDARIANSPHYLUM CNIDARIA

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

Nematocysts

• Are poison filled stinging structures.

• Used for defense and to capture prey.

Two Body Forms

• Polyp

• Vase-shaped body

• Medusa

• Bell-shaped body

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

Reproduction

• Asexual- budding

• Sexual- external fertilization in water

Class Scyphozoa

• Medusa Stage

• Ex. jellyfish

Class Hydrozoa

• Polyp/Medusa Form

• Ex. Portuguese-Man-Of-War

• Ex. Hydra

Class Anthozoa

• Polyp Stage• Destroyed by human

activity• Ex. Sea Anenome and

Coral

Cnidarian Life Cycle

• http://glencoe.mcgraw-hill.com/sites/0078695104/student_view0/unit7/chapter24/concepts_in_motion.html#