Transcript Unit 5: Animals – Sponges, Cnidarians, & Worms

Invertebrates Part 1
Animal Characteristics
Sponges and Cnidarians
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
• Asymmetrical 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: asexualbud; Regenerate body parts
The Anatomy of a Sponge
Section 26-2
Osculum
Water flow
Central cavity
Pores
Choanocyte
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
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Simple Sponge Morphology
11
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. Permission required for reproduction or display.
Sponge Body Forms
13
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
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Class Hexactinellida
Euplectella
• Spicules
– Siliceous
– 6 rays
16
Class Demospongiae
Spongia
• Spicules
– Siliceous
– spongin
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18
Sponge Reproduction
Asexually:
• Fragments break off and grow into
new individuals
• Buds form from sides of parent
sponge, break offnew sponge
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
Porifera Platyhelmithes Mollusca Arthropoda
Cnidaria
Nemertea
Annelida
Echinodermata Hemichordata
Lophophores Chordata
Precambrian
Protozoans
Before 670 MYA
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How much did your brain
“sponge” in?
1. What are the basic characteristics of
Animals?
2. What does the word Porifera mean?
3. What type of structure?
a.
b.
c.
d.
provide the skeleton of a sponge?
Filter food out of the water?
Allows water to exit the sponge?
Class Hexactinellida has spicules made of?
4. How do sponges survive without body
systems? (Be specific)
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Hypothesis of Multicellularity
23
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
• 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
Label the hydra on
your notes!
• Nerve net: net of nerves that
allow impulses to travel around
the body, senses the
environment
Without Body Systems, how
do they survive?
• Nervous: Cephalization absent; Nerve Netconducts 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
Mesoglea
Gastrovascular cavity
Mouth/anus
Mouth/anus
Gastrovascular
cavity
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