Unit 19
Invertebrate Animals
Photo Credit:
Photograph by Chris Newbert/Minden Pictures
Introduction
In this unit we will introduce
characteristics of Kingdom
Animalia and focus on
invertebrate animals (that
lack a backbone).
Photo Credit:
Photograph by Chris Newbert/Minden Pictures
Characteristics of Animals

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Eukaryotic; their
cells have a
nucleus w/
specialized
organelles
Cells DO NOT
have cell walls
Multicellular
Heterotrophs;
animals cannot
make their own
food
Animal Body Symmetry

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Asymmetry – lack of symmetry (EX sponge).
Radial symmetry – circular arrangement around a central
point (EX sea star).
Bilateral symmetry – arrangement along a middle plane
(EX human).
http://www2.estrellamountain.edu/faculty/far
abee/biobk/bodysymm.gif

Review of Taxonomy

There are nine
categories of
taxonomy and all
living things are
sorted by their
genetic
relationships and
characteristics they
possess.
Species [the most specific]
Genus
Family
Order
Class
Phylum
Kingdom
Domain [the most general]
Domain Eukarya
Kingdom Animalia
Phylum Porifera TxBkRef pg. 693-697

AKA Sponges are the
oldest and simplest
and probably most
unusual animals.
 Name means
“pore-bearer”
 Sponges are sessile
and do not move
(as adults).
http://www.lpdatafiles.com/data/mso2003/SCUBA%20SPONGES.jpg
Sponge Cont.
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No symmetry
(asymmetry)
Sponges lack special
tissues
They have structures
that pump water
through their body to
respire and filter food,
and excrete waste.
Sponge Video
http://www.scubaheartland.com/photos/sponges.jpg
Sponge Photos
http://www.padi.com/scuba/uploadedImages/Scuba_Diving_Trips/Scuba_Diving_Resort_Vacations/Diver%
20with%20Sponge%20Coral%20Belize%20Barrier%20Reef_Image%20Copyright%202009%20%20Tony%20Rath%20of%20Tony%20Rath%20Photography%20www.tonyrath.com.jpg
Domain Eukarya
Kingdom Animalia
Phylum Cnidaria TxBkRef pg. 698-705

http://san-pedro-aquarium.california-california.info/Cnidarians.gif
Think floating jellyfish and
anemones!
 Found all over the
world, cnidarians (C is
silent) are soft bodied,
carnivorous animals
with stinging tentacles.
 Some are sessile, some
motile (they move)

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http://classconnection.s3.amazonaws.com/589/flashcar
ds/720467/png/screen-capture-2.png
Radial symmetry
Cnidocytes – unique
cells on the tentacles
that contain stinging,
poisonous barbs to
capture prey
Cnidarians make up
the world’s coral
reefs
http://www.corkvisioncentre.com/cor
kvisioncentre/Images/UnderwaterRealm-2.jpg
Cnidarians Cont.
Cnidarians Photos
http://www.oceanicresearch.org/education/wonders/cnidarian.html
http://www.mbgnet.net/salt/animals/1coral.jpg
Photos Cont.
http://www.ucihs.uci.edu/biochem/steele/Physalia.htm

Jellyfish Video
http://www.ima
gequest3d.com
/photos/combje
llies/index.htm
Domain Eukarya
Kingdom Animalia
Phylum Platyhelminthes TxBk Ref pg. 706-710

http://www.ucmp.berkeley.edu/platyhelminthes/pseudobiceros.jpg
AKA Flatworms are unsegmented (no rings) and
appear flat, most only a
few millimeters thick.
 They move to obtain
food and escape
predators.
 Bilateral symmetry,
and cephalization (a
head region)
Flatworm Cont.
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They have a single digestive opening, a
mouth/anus in which food enters and undigested
waste leaves.
Do not need a circulatory or respiratory system to
transport materials, but use diffusion.
http://www.emc.maricopa.edu/faculty/farabee/biobk/flatworm.gif
Flatworms Cont.
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They can be both
carnivorous or
parasitic (EX
tapeworms can live
inside the human
intestines).
Flatworm Video 1
Flatworm Video 2
http://biology.ucok.edu/AnimalBiology/Platyhelminthes/tapeworms.jpg
Domain Eukarya
Kingdom Animalia
Phylum Nematoda TxBkRef pg. 711-713

http://www.robots4farms.com/scubadivingpictures_files/daphneislet_files/99_j
ms_RoseRibbonWorm_90p_P2250080.jpg
AKA Roundworms, are
unsegmented worms that
can be microscopic or a
meter!
 Most roundworms are free
moving and are found in
the soil or water; many are
parasites that live in
plants and animals.
 Bilateral symmetry
Roundworms Cont.
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Humans can be infected
with roundworms such as
Ascaris lumbricoides which
causes Ascariasis
[affecting 1.3 billion
people worldwide].
Roundworm parasites can
be spread through
contaminated produce,
unwashed hands, and raw
fish.
Roundworm Video
http://www.nejm.org/doi/full/10.1056/NEJMicm054199
Roundworms Photos
With over 250,000
known cases across
the United States,
canine heartworm
disease continues to
plague our pets.
Domain Eukarya
Kingdom Animalia
Phylum Annelida TxBkRef pg. 728-733

Think earthworms
and leeches!
 AKA worms with
segmented
bodies
 The name means
“little rings”.
http://www.seawater.no/fauna/annelida/images/DSC08786.jpg
Segmented Worms Cont.
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Most are free moving and are found in the soil as
decomposers or in water.
Bilateral symmetry
Have fully formed
organ systems
with a simple
brain, nerves,
heart and blood
vessels, etc.
Worm Video 1
Worm Video 2
http://www.blc.arizona.edu/courses/schaffer/182/Annelid.jpg
Annelid Photos
http://img.ehowcdn.com/article-newthumbnail/ehow/images/a08/7n/4n/annelidworms-800x800.jpg
http://www.corbisimages.com/images/67/CC068D92-8C8A-4D6F-AC05-0092B9A74CF7/FL006311.jpg
Domain Eukarya
Kingdom Animalia
Phylum Mollusca TxBkRef pg. 721-727

Think snails, clams,
and the octopus!
 Characterized by
soft bodies that is
sometimes with a
shell.
 Bilateral symmetry
 Have fully formed
organ systems
http://www.greenfacts.org/images/glossary/mollusk.jpg
Some Classes of Mollusks
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Class Gastropoda
(mollusks with
shells; EX snails)
Snail Video
http://images.natureworldnews.com/data/images/full/1255/giant-african-landsnail.jpg?w=600
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Class Bivalva
(mollusks with a
hinged shell; EX
clams and oysters)
Clam Video
http://www.oceanwideimages.com/images/8256/large/giant-clam-24M1600-28.jpg
http://www.gochart.com/dig_photo/clams.JPG
Some Classes of Mollusks Cont.
Some Classes of Mollusks Cont.
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Class Cephalopoda
(most advanced,
intelligent mollusks;
EX nautilus, squid,
octopus
Ink to confuse
predators
 Can manipulate skin
colors
 Tentacles to attack
prey
Octopus Video
Squid Video

http://marinebio.org/upload/_cephs/Hapalochlaena-maculosa/3.jpg
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Mollusks Photos
http://www.uni-giessen.de/uni/broschuere/FB08-Nautilus.jpg
http://www.saczoo.com/3_kids/20_camoufla
ge/images/octupus.jpg
http://www.arkive.org/humboldt-squid/dosidicus-gigas/image-G131180.html
Domain Eukarya
Kingdom Animalia
Phylum Echinodermata TxBkRef pg. 763-769

Think sea stars, sand dollars,
and sea urchins!
 Means "spiny skin“ and these
organisms live only in the
ocean.
 Radial symmetry
 Have fully formed organ
systems
 Echinoderms have the ability
to regenerate their limbs.
 Echinoderm Video 1
 Echinoderm Video 2
http://www.museums.org.za/bio/images/mb/mb0556x.jpg
Echinoderms Photos
http://www.wetwebmedia.com/ca/cav1i4/echinoderms/sea_apple.jpg
http://www.arkive.org/purple-sea-urchin/strongylocentrotuspurpuratus/image-G69185.html
These are the elaborate filterfeeding tentacles of a Sea Apple.
Echinoderms Photos Cont.
http://www.arkive.org/sea-star/odontaster-validus/
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda TxBkRef pg. 741-754

Think butterflies, shrimp, and
spiders!
 Means “jointed feet”
 Bilateral symmetry
 Have fully formed organ
systems

http://content.answers.com/main/content/wp/en/th
umb/9/99/150px-Zorak-Mantis.png

Sensing antennae for sound,
odor too
Well developed eyes
Arthropods Cont.
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They have segmented
bodies fused into
larger body regions.
Exoskeleton - made of
chitin; is a hard
covering outside of
body for support and
protection
Molting –; shedding of
old exoskeleton
required for an
arthropod to grow
Arthropod Video
http://www.vifishandwildlife.com/Education/FactShe
et/Images/Lobster.jpg
Some Classes of Arthropods
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Class Arachnida –have four pairs of walking legs, chewing
mouthparts, and two body segments; EX spiders, ticks,
and scorpions
Spider Video
http://www.arkive.org/arabian-fat-tailed-scorpion/androctonus-crassicauda/
http://animals.nationalgeographic.com/animals/bugs/blackwidow-spider/?source=A-to-Z
Sun Spider Mouth Close Up Image
Some Classes of Arthropods Cont.
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Class Crustacea – chewing
mouthparts, two pair of
antennae, and two body
segments typically with five legs
with clawsc; EX shrimp, crabs
Crab Video
http://www.mbari.org/seminars/2004/fall200
4/shrimp.jpg
http://www.arkive.org/coconut-crab/birgus-latro/image-G8535.html
Some Classes of Arthropods Cont.
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Class Insecta– have mouthparts, most have compound
eyes, antennae and three body segments with six legs; EX
grasshoppers, flies, and beetles
http://img.allw.mn/content/www/2010/07/10-coolest-insects/brentidweevils_10-coolest-insects.jpg
http://www.arkive.org/elephant-beetle/megasoma-elephas/imageG104875.html
Ants lovingly nurture various kinds of
true bugs (Hemiptera), often stroking
them gently and protecting them from
predators and parasites. The bugs
reward the ants with sugary nectar in the
form of honeydew that they secrete as a
waste product from feeding on the sap
of the plants. These are scale insects
(the red blobs) being tended by
redheaded cocktail ants in Kenya. In
many ways this relationship is similar to
humans keeping cattle or other livestock
and milking them.
Photograph by Dino Martins
National Geographic
The Evolution of Invertebrates
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Fossil evidence shows that the
first animals [sponges – shown
to the right] evolved from
Protists with flagella about 650
million years ago.
 Sponge Video
The second group to evolve were
Cnidarians; but because they are
soft bodied, they do not fossilize
well [estimates are about 630
million years ago].
http://www.dailymail.co.uk/sciencetech/article2097609/Fossils-Namibia-worlds-oldestanimal-life--oldest-ancestor-sponge-760million-years-ago.html
This fossil jellyfish shows
similarity to the modern
jellyfish, Cunina (right). It was
one of four different types of
jellyfish dated back to the
Cambrian by researchers in
2007. These ancient jellyfish
showed the same complexity
as modern jellyfish, meaning
they either developed rapidly
500 million years ago, or
today’s varieties are much
older. Image
Invertebrate Evolution Cont.
http://www.fossilmuseum.net/CambrianExplosion/Annelid2/aworm.htm

Flat and roundworms are thought to have evolved next, but
their soft bodies make it hard to find fossil evidence.
Segmented worms [annelids] evolved first in the sea, about
540 million years ago.
http://www.fossilmuseum.net/Fossil_Sites/Lebane
se-Lagerstatt/Annelida/Annelidab.htm

Invertebrate Evolution Cont.

Mollusks evolved next, about 500 million years ago – many
types of shelled mollusks, like the nautilus, were found in
the early oceans of Earth.
 A fossilized nautilus [left], the modern [right]
 Nautilus Video
http://qrius.si.edu/browse/object/10022862#.U2jhJYH_xyI
http://www.arkive.org/nautilus/nautilus-pompilius/image-G68046.html
http://en.wikipedia.org/wiki/File:Walliserops_trifurcatus,_Early_Devonian,_Timr
hanrhart_Formation,_Jbel_Gara_el_Zguilma,_Draa_Valley,_Morocco__Houston_Museum_of_Natural_Science_-_DSC01584.JPG
Invertebrate Evolution Cont.
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Arthropods evolved about 500
million years ago; they began in
the seas, like their early
ancestor, the trilobite [see
image, extinct for 248 million
years].
Arthropods became the first land
animals, circa 300 million years
ago.
 Arthropod Video
http://www.evolutiontextbook.org/content/free/figures/10_EVOW_Art/23_EVOW_CH10.jpg
Invertebrate Evolution Cont.
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Echinoderms are
considered the group most
closely connected to
chordates; they first
appeared in the fossil
record about 540 million
years ago.
Echinoderms and
chordates both develop
similarly after fertilization
[they are deuterostomes].
http://en.wikipedia.org/wiki/File:Protovsdeuterostomes.svg