Download What is an Animal? Chapter 25

What is an Animal?
Chapter 24
Animal Movie (15 min)
24-1 Animal Characteristics
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Eukaryotic
Multicellular
Heterotrophic
Mobile at some stage
Support
• Support
– Invertebrates – lack backbones
• May have external skeleton- exoskeleton
• May have internal skeleton – endoskeleton
– Vertebrates – have backbones & endoskeleton
Animal Development
• Most have Sexual Reproduction
• Egg + Sperm = Fertilization
– Can be internal or external fertilization
– Forms a single celled zygote
– Undergoes cell division during cleavage to
form two cells
– Hermaphrodites – have both male and female
reproductive parts
Cell Division
• Once it is two cells, now called an embryo
• Cells keep dividing to form a hollow ball called a
blastula
• Cells begin to fold inward to form a gastrula, this
forms an outer layer (ectoderm) and an inner layer
(endoderm)
• Ectoderm develops into skin and nervous tissue
• Endoderm develops into digestive track and
organs associated with digestion
Cell Division
Gastrulation
Tissue Development
• Endoderm – inner layer that develops into
digestive organs and the lining of digestive
tract
• Mesoderm - middle layer that develops into
muscles, circulatory system, excretory
system, and in some respiratory system
• Ectoderm – outer layer that develops into
nervous tissue and skin
• Sea Urchin - Blastula
Germ Layer Development
24-2 Animal Body Plans
See Page 699!
Symmetry
View of the left side of a bilaterally symmetrical animal. Drawing by
John Norton.
Symmetry
• Asymmetry – no symmetry
– Ex. Sponges
Radial Symmetry
• Radial – can be divided along any plane
through a central axis
– Examples: Hydra and Jellyfish
Bilateral Symmetry
• Bilateral – can be divided down its length
into mirror images
• Examples: Humans and dogs
Body Plans
• Acoelomate – has three body layers, but no
cavity
• Example – Flatworm
Acoelomate
Pseudocoelomate
• Pseudocoelomate – have three body layers,
with a fluid-filled body cavity between the
endoderm and mesoderm layers
• Example: Roundworms
Pseudocoelomate
Coelomate
• Coelomate – have three body layers, with a
fluid-filled body cavity within the
mesoderm layer
• Examples – earthworms, insects, fish
Coelomate
Protostome vs. Deuterostome
• Protostome animals develop the mouth first
– Examples include earthworms and insects
• Deuterostome animals develop the anus first
– Examples include echinoderms and vertebrates
Chapter 24.3
Sponges, Cnidarians
Phylum Porifera
Sponges:
• Invertebrates
• Sponges can live
to be 100+ years
old.
Yellow Tube Sponge
Porifera Body Structure
• Asymmetrical
• No Tissues (ecto-, endo-,
mesoderm)
• Just two layers of cells
with a jelly-like
substance in between
• Porus
Porifera Body Structure
• Pore cells: These surround the pores on the
outside of the sponge. The pores are where
water and food enter the sponge
• Epithelial cells: These are the outer ‘skin’
of a sponge. These cells can contract to
close the pores, if needed
• Collar cells: These line the inside of the
sponge. These cells have flagella that cause
the current of water
Sponge Anatomy
http://lcmrschooldistrict.com/roth/Biology_animate/Ch26/ActiveArt/
Porifera Body Strurcture
Spicules: Between sponge cells
– Not cells
– Make up the ‘skeleton’
support system
– Sponge structure video
- sponge movie
Porifera Support
• Archaeocytes cells
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Can move and change shape
Involved in digestion
Make egg and sperm
Make spicules (small
needle-like structures)
Porifera Support
• Some freshwater sponges can
produce gemmules, a seedlike unit
that can survive cold temperatures.
• Spicules provide support.
– Can be sharp (made of calcium
carbonate matter)
– Can be made out of silica
– Can be more flexible (like the
fibrous protein spongin)
Porifera Motility
• Larvae:
Free-swimming
• Adult Sponge: sessile, usually on the sea
floor
Porifera Feeding and Digestion
• Filter feeder
- food particles pass
through the pores.
- Particles cling to cells
- Cells digest food
individually.
•finger or eyed sponge
•bright yellow sponge
Porifera Reproduction
• Sexually
– Most sponges are hermaphrodites, have both sexes,
which help insure fertilization with sessile animals.
– Most sponges are fertilized internally.
– Sperm that is carried by water currents.
– The larvae can swim for a few days until they attach to
a surface.
• Asexually
– fragmentation
– budding
3 Classes/Types of Sponges
• Demospongiae
– spongin
• Calcarea
– calcium
• Hexactinellida
– silica
Sponge Review
System Type
Sponges System
Muscular-Skeletal
A sponge is a hollow tube with many pores or openings. The skeleton is made
of calcium carbonate, silicon or spongin spicules.
Digestion
A sponge takes in food via the water that flows through the pores.
Nervous
A sponge has a very low level reaction to the world around it and does not
have a brain per se.
Circulation
A sponge has water flow in through the pores. The water contains the food
and oxygen the sponge needs.
Respiration
A sponge takes in water through its pores, and then canals that move the
water all throughout the sponge. Then the oxygen from the water is used.
Reproduction
A sponge reproduces by budding, fragmentation and also sexually.
Excretion
A sponge has carbon dioxide and other wastes removed as the water moves
in and out through the pores.
Symmetry
A sponge is asymmetrical or has radial symmetry.
Coloration
A sponge is white, red, orange, green, yellow, brown, purple, black
Cnidarians
Jellyfish and Sea Anemones
Jellyfish
Cnidarian Features
• Mostly marine organisms
• Radial symmetry
• Two cell layers with only one body
opening
• Tissues made of ectoderm and endoderm
• Simple nervous system called the nerve net
• Obtain oxygen by diffusion
New Scyphozoan Jellyfish Discovered (May 2003)
Tiburonia granrojo (Big Red)
was taken during a remotely
operated vehicle (ROV) dive on
the Gumdrop Seamount off the
coast of California. Can be up
to 1 m in diameter. Lives
between 650-1500 m deep.
Sea Anemones
Coral Polyps
Cnidarian Digestion
• Cnidocytes
– Stinging cells on tentacles that capture prey
– Comprised of nematocysts
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A capsule
A coiled, threadlike tube
Poison
Barbs, sharp enough to penetrate a crab shell
It only takes 3/1000ths of a second for the nematocyst to discharge
Cnidarian Reproduction
• Asexual is through budding
• Sexual reproduction is through fertilization
of eggs and sperm
• Can be internal or external fertilization
Cnidarian Reproduction
Two life stages of Cnidaria:
1. Medusa- floating
2. Polyp- sessile
Life Cycle of a Jellyfish
Cnidarian Classes/Types
Class Hydrozoa
• Have both the polyp and medusa stages
of life
• Can form colonies
•Two kinds:
1. Hydroids – hydra
2. Siphonophores – colonies
of hydra
ex. Portuguese Man of War
Colony of Hydra
Siphonophores
Portuguese Man of War
A Violet Snail eating
a siphonophore
Cnidaria Types
Class Scyphozoa(jellyfish)
• Transparent
• Medusa is dominant
• Some jellyfish have
fatal stings.
Cnidaria Types
Class Anthozoa
• Polyp stage is dominant
• Live in colonies
• Build protective calcium
shelters
• Symbiotic with a
photosynthetic protist
• Use tentacles to feed
1. Corals- live in colonies
2. Sea Anemone-Live individually
the phylum of stinging animals video
http://www.lophelia.org/movies/movies_reefs.htm
movie on coral reef
Mutualistic Cnidaria
• Crab + Sea anemone= sea anemone grows
on crab’s shell to protect crab and collect
food scraps
Commensalism Cnidaria
• Clown fish + Sea anemone =
Anemone stings predators of
clown fish but not the clown
fish
Human Bone Surgery
• Coral contains Hydroxyapatite which has
the same composition as human bone.
• The coral can be grafted onto human bones
during:
– Face reconstruction
– Jaw reconstruction
– Arm and leg surgery
Knee Surgery
Ctenophora
• Comb jellies – are jelly-like with radial
symmetrical bodies
• They have no stinging cells with which to
stun their prey, but they are voracious filter
feeders
• Eight rows of combs made of cilia for
motion
• Reminds me of the movie – The Abyss
Characteristics of Ctenophora
1. Radial symmetry
2. Multicellular, few tissues, some organs and
organelles.
3. Body contains an internal cavity,a mouth, and
anal pores.
4. Swims by means of plates of cilia (the combs)
5. Reproduction mostly sexual as hermaphrodites,
occasionally asexual.
6. Has a well developed nerve net.
7. Has a distinct larval stage which is planktonic.
8. Lives in marine environments.
9. All are carnivorous.
Colloblasts
– Sticky threads used in prey
capture
Data Analysis Lab
Page 714