Chapter 26: Sponges and Cnidarians

26-1 Introduction to the Animal Kingdom What makes animals different from the previous organisms we have covered so far this year?

The Animal Kingdom Multicellular Eukaryotic Heterotrophs Cells lack 26-1 Introduction to the Animal Kingdom The Animal Kingdom Multicellular Eukaryotic Heterotrophs Cells lack cell walls 95% are invertebrates

26-1 Introduction to the Animal Kingdom

26-1 Introduction to the Animal Kingdom

What Animals Do to Survive 26-1 Introduction to the Animal Kingdom What Animals Do to Survive Feeding Respiration Circulation Excretion Response Movement Reproduction

1. Feeding Modes of ingestion of nutrients Carnivores Detrivores 26-1 Introduction to the Animal Kingdom 1. Feeding Modes of ingestion of nutrients Carnivores Detrivores Herbivores

2. Respiration Taking in oxygen, releasing carbon dioxide Lungs Gills 26-1 Introduction to the Animal Kingdom 2. Respiration Taking in oxygen, releasing carbon dioxide Lungs Gills Skin

3. Circulation Movement of materials in the body Diffusion Heart Pump 26-1 Introduction to the Animal Kingdom 3. Circulation Movement of materials in the body Diffusion Heart Pump

26-1 Introduction to the Animal Kingdom 4. Excretion Removal of nitrogen waste out of body to maintain homeostasis Diffusion Kidney

5. Response Responding to outside stimuli using nerve cells 26-1 Introduction to the Animal Kingdom 5. Response Responding to outside stimuli using nerve cells

6. Movement Attached to a single spot or motile 26-1 Introduction to the Animal Kingdom 6. Movement Attached to a single spot or motile

26-1 Introduction to the Animal Kingdom 7. Reproduction

Trends in Animal Evolution 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Though there are differences in whether an animal has a backbone or not, there are some common trends: 1. Cell Specialization 2. Body Symmetry 3. Cephalization 4. Body Cavity Formation

26-1 Introduction to the Animal Kingdom 1. Cell Specialization Animal cells have evolved to carry out specific functions:

1. Cell Specialization Reasons why cell specialization is important: 26-1 Introduction to the Animal Kingdom 1. Cell Specialization Reasons why cell specialization is important: Allows for animals to perform many different functions Causes a greater efficiency in survival

Early Embryonic Development 26-1 Introduction to the Animal Kingdom Early Embryonic Development Animals that reproduce sexually begin life after fertilization as a zygote (fertilized egg) Zygote undergoes a series of divisions Blastula forms (simple ball of cells) Blastula fold in on itself forming blastopore Blastopore leads into a central tube

Early Embryonic Development 26-1 Introduction to the Animal Kingdom Early Embryonic Development

Protostome Animals mouth forms from blastopore (most invertebrates) 26-1 Introduction to the Animal Kingdom Protostome Animals mouth forms from blastopore (most invertebrates) Deuterostome Animals anus forms from blastopore (echinoderms and vertebrates

Early Embryonic Development 26-1 Introduction to the Animal Kingdom Early Embryonic Development Endoderm inner Mesoderm middle Ectoderm outer Cells differentiate into 3 germ layers

Early Embryonic Development 26-1 Introduction to the Animal Kingdom Early Embryonic Development

2. Body Symmetry Ability to divide a body into 2 equal halves 26-1 Introduction to the Animal Kingdom 2. Body Symmetry Ability to divide a body into 2 equal halves

2. Body Symmetry Planes of symmetry: Dorsovental Axis (Sagittal Plane) 26-1 Introduction to the Animal Kingdom 2. Body Symmetry Planes of symmetry: Dorsovental Axis (Sagittal Plane) Cuts the body into right and left sides

2. Body Symmetry Planes of symmetry: Transverse Axis 26-1 Introduction to the Animal Kingdom 2. Body Symmetry Planes of symmetry: Transverse Axis Produces a “cross-section” of the body Divides the body into “Anterior” and “Posterior” regions

2. Body Symmetry Regions of the body: Dorsal: Upper 26-1 Introduction to the Animal Kingdom 2. Body Symmetry Regions of the body: Dorsal: Upper Posterior: Rear End Anterior: Front Ventral: Lower

26-1 Introduction to the Animal Kingdom Trends of Evolution There are two more characteristics that most animals share in addition to “Cell Specialization” and “Body Symmetry” 3. Cephalization 4. Body Cavity Formation

26-1 Introduction to the Animal Kingdom 3. Cephalization Refers to the characteristic that more sense organs and nerve cells are located at the anterior part of the body than anywhere else

26-1 Introduction to the Animal Kingdom 3. Cephalization Allows animals to respond quicker and in more complex ways to stimuli

26-1 Introduction to the Animal Kingdom 4. Body Cavity Formation Body cavity is a fluid-filled space that contains the organs

26-1 Introduction to the Animal Kingdom 4. Body Cavity Formation This allows space for internal organs to keep their shape and to grow properly

Evolutionary Relationships 26-1 Introduction to the Animal Kingdom

26-2 SPONGES

Sponges Phylum Porifera Have tiny openings, or pores, all over their bodies Sessile: they live their entire life attached to a single spot They are animals. Why…?

Click Picture To Watch a 3 Minute Sponge From and Function Video 26-2 Sponges Sponges are Animals Click Picture To Watch a 3 Minute Sponge From and Function Video Multicellular Heterotrophic No cell walls Contain a few specialized cells

Form and Function in Sponges Have nothing resembling a mouth or gut Have no tissues or organ systems Simple functions are carried out by a few specialized cells

Asymmetrical Have no front or back ends, no left and right sides 26-2 Sponges Asymmetrical Have no front or back ends, no left and right sides A large, cylindrical water pump The body forms a wall around a large central cavity through which water flows continually

26-2 Sponges

Specialized Cells Choanocytes Osculum 26-2 Sponges Specialized Cells Choanocytes Specialized cells that use flagella to move a steady current of water through the sponge Osculum Water leaves through the large hole at the top of the sponge

26-2 Sponges Choanocytes Specialized cells that use flagella to move a steady current of water through the sponge Filters several thousand liters/day

26-2 Sponges Osculum A large hole at the top of the sponge, through which water exits The movement of water provides a simple mechanism for feeding, respiration, circulation and excretion

Specialized Cells spicule archaeocytes spongin 26-2 Sponges Specialized Cells spicule is a spike-shaped structure made of chalklike calcium carbonate or glasslike silica archaeocytes are specialized cells that move around within the walls of the sponge and make spicules. spongin network of flexible protein fibers that make up the internal skeleton of a sponge.

26-2 Sponges Simple Skeleton Spicule: a spike-shaped structure made of chalk-like calcium carbonate or glasslike silica in hard sponges Archaeocytes: specialized cells that make spicules

26-2 Sponges

Click Picture To Watch a 5 Minute Sponge Filter Feeding Video 26-2 Sponges Sponge Feeding Click Picture To Watch a 5 Minute Sponge Filter Feeding Video Filter feeders Sift microscopic food from the water Particles are engulfed by choanocytes that line the body cavity

Respiration, Circulation, & Excretion 26-2 Sponges Respiration, Circulation, & Excretion Rely on the movement of water through their bodies to carry out body functions As water moves through the cavity: Oxygen dissolved in the water diffuses into the surrounding cells Carbon dioxide and other wastes, diffuse into the water and are carried away

Response No nervous system 26-2 Sponges Response No nervous system Many sponges protect themselves by producing toxins that make them unpalatable or poisonous to potential predators

Click Picture To Watch A 2 Minute Sponge Reproduction Video 26-2 Sponges Reproduction Click Picture To Watch A 2 Minute Sponge Reproduction Video Sexually or asexually A single spore forms both eggs and sperm; usually at different times

26-2 Sponges Sexual Reproduction Internal fertilization: Eggs are fertilized inside the sponge’s body Sperm are released from one sponge and carried by currents to the pores of another sponge

Asexual Reproduction Budding 26-2 Sponges Asexual Reproduction Budding Gemmules: groups of archaeocytes surrounded by spicules

26-2 Sponges Ecology of Sponges Ideal habitats for marine animals such as snails, sea stars, sea cucumbers, and shrimp Mutually beneficial relationships with bacteria, algae and plant-like protists Many are green due to these organisms living in their tissues

26-2 Sponges Ecology of Sponges Attached to the seafloor and may receive little sunlight Some have spicules that look like cross-shaped antennae Like a lens or magnifying glass, they focus and direct incoming sunlight

26-3 CNIDARIANS

Cnidarians Phylum Cnidaria Hydras, jellies, sea anemones, and corals Soft-bodied Carnivorous Stinging tentacles arranged in circles around their mouths Simplest animals to have body symmetry and specialized cells

Cnidocytes Stinging cells that are located on their tentacles 26-3 Cnidarians Cnidocytes Stinging cells that are located on their tentacles Used for defense and to capture prey

26-3 Cnidarians Nematocyst A poison-filled, stinging structure that contains a tightly coiled dart Found within cnidocytes

Click Picture To Watch a 2 Minute Feeding Anemone Video 26-3 Cnidarians Click Picture To Watch a 2 Minute Feeding Anemone Video

Click Picture To Watch a 3 Minute Stinging Jellyfish Video 26-3 Cnidarians Click Picture To Watch a 3 Minute Stinging Jellyfish Video

Form and Function in Cnidarians Only a few cells thick Simple body systems Most of their responses to the environment are carried out by specialized cells and tissues

26-3 Cnidarians Radially Symmetrical Central mouth surrounded by numerous tentacles that extend outward from the body Life cycles includes a polyp and a medusa stage

26-3 Cnidarians Body Plan Polyp: cylindrical body with arm-like tentacles; mouth points upward Medusa: motile, bell-shaped body; mouth on the bottom

Phylum Cnidarian 26-3 Cnidarians Medusa Polyp Tentacles Mesoglea Epidermis Mesoglea Gastroderm Tentacles Mouth/anus Gastrovascular cavity Mesoglea Gastrovascular cavity Mouth/anus Tentacles Medusa Polyp

26-3 Cnidarians Feeding Polyps and medusas have a body wall that surrounds an internal space: the gastrovascular cavity Gastrovascular cavity: a digestive chamber with one opening Food enters and wastes leave the body

Respiration, Circulation, & Excretion 26-3 Cnidarians Respiration, Circulation, & Excretion Following digestion, nutrients are usually transported throughout the body by diffusion Respire and eliminate wastes by diffusion through body walls

26-3 Cnidarians Response Specialized sensory cells are used to gather information from the environment Nerve net: loosely organized network of nerve cells that together allow cnidarians to detect stimuli Distributed uniformly throughout the body in most species In some species it is concentrated around the mouth or in rings around the body

26-3 Cnidarians

26-3 Cnidarians Response Statocysts: groups of sensory cells that help determine the direction of gravity Ocelli: eyespots made of cells that detect light

26-3 Cnidarians Movement Hydrostatic skeleton: a layer of circular muscles and a layer of longitudinal muscles that enable cnidarians to move

Reproduction: Sexually and Asexually 26-3 Cnidarians Reproduction: Sexually and Asexually Polyps can reproduce asexually by budding External sexual reproduction The sexes are separate-each individual is either male or female Both egg and sperm are released into the water

26-3 Cnidarians

26-3 Cnidarians

26-3 Cnidarians

Groups of Cnidarians Jellies (formerly jellyfishes) Hydras and their relatives Sea anemones Corals

26-3 Cnidarians

Groups of Cnidarians Class Scyphozoa: “cup animal” Jellyfish

Classes of Cnidarians Class Scyphozoa Spend most of their lives as medusa The polyp form is limited to a larva stage

Classes of Cnidarians Class Scyphozoa The largest jellyfish ever found is 4 meters in diameter with tentacles more than 30 meters in length Most species are harmless, many can cause servere allergic reactions/even kill people

26-3 Cnidarians

26-3 Cnidarians

Groups of Cnidarians Class Hydrozoa: Hydras; Portuguese Man of War

Classes of Cnidarians Class Hydrozoa The polyps of most hydrozoans grow in branching colonies that sometimes extend more than a meter. Within a colony, the polyps are specialized to perform different functions. EX: One polyp forms a balloon-like float that keeps the entire colony afloat Portuguese Man of War

Classes of Cnidarians Class Hydrozoa Most common in freshwater hydrozoan is a hydra Lack medusa stage (solitary polyp) Reproduce sexually (producing eggs and sperm in the body wall) and asexually (budding) a few species are hermaphroditic Click Picture To Watch a 2 Minute Hydra Budding Video

26-3 Cnidarians

Groups of Cnidarians Class Anthozoa: “flower animal” Sea Anemones and Corals

Classes of Cnidarians Class Anthozoa Grow only as polyps / no medusa stage Central body that is surrounded by tentacles Many species are colonial (composed of many individual polyps)

Classes of Cnidarians Class Anthozoa Corals and sea anemones reproduce sexually by producing free swimming larvae The free swimming larvae attach to rocks and then form polyps Also can reproduce by budding

Classes of Cnidarians Class Anthozoa Forming Coral Reefs Formed when hard coral from layers of skeleton (CaCO3) Algae forms a sybiotic relationship with coral

Click Picture To Watch a 1 Minute Coral Budding Video 26-3 Cnidarians Click Picture To Watch a 1 Minute Coral Budding Video

26-3 Cnidarians

Click Picture To Watch a 5 Minute Coral Spawn Video 26-3 Cnidarians Ecology of Corals The worldwide distribution is determined by: Temperature Water depth Light intensity Many suffer from human activity Coral bleaching has become common Global warming may add to the problem Click Picture To Watch a 5 Minute Coral Spawn Video