Transcript 25 PowerPoint – Invertebrates

CHAPTER 25
Introduction to Animals
Characteristics of all animals –
Kingdom Animalia
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Multicellular – contain
many cells
Heterotrophic – eat other
organisms for food
Eukaryotic – contain a
nucleus
Lack Cell Walls
Two categories of Animals
Invertebrates
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Lack a backbone
33 phyla
Sea stars, worms,
jellyfish, insects
Chordates
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Dorsal hollow nerve cord
Notochord – (embryo)
Tail
Pharyngeal pouches
(paired structures)
Most are vertebrates
Fish, amphibians, reptiles,
birds, mammals
What Animals Do to Survive

1) Maintain homeostasis - keep their internal
environment relatively stable
 Reptiles,
birds, and mammals cannot excrete salt. Ex.
the marine iguana, have adaptations that allow them
to remove salt from their bodies.
What Animals do to Survive

2) Gather and Respond to Information
The nervous system gathers information using receptors cells
that respond to sound, light, chemicals, and other stimuli.
 Other nerve cells collect and process that information and
determine how to respond.

What Animals do to Survive

3) Obtain and Distribute Oxygen and Nutrients
 Obtain
oxygen (Respiratory)
 Obtain nutrients (Digestive)
 Transport (Circulatory)
What Animals do to Survive

4) Collecting and Eliminating C02 and other waste
 Metabolic
processes make waste (CO2, ammonia, etc.)
 Wastes are removed through the respiratory and
excretory systems (via the circulatory system)
What Animals do to Survive

5) Reproduction
 Sexual
reproduction – genetic diversity
 Asexual reproduction – genetically identical to the
parent
 Increases
numbers quickly but does not generate diversity
Levels of Organization
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Cells
Tissues – a group of cells with a specific function
Organs – a group of tissues that work together
Organ Systems – a group of organs that work
together
Body Symmetry
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Radial Symmetry = many
imaginary planes can be
drawn through the center of
the body to divide it equally
in halves
Bilateral Symmetry = a single
plane divides the body into
left and right sides that are
mirror images of one another
Anatomy Terms
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Dorsal = Back (Upper)
Ventral = Belly (Lower)
Anterior = Head (Front)
Posterior = Back (Rear end)
A Body Cavity

Body Cavity = a space
between the digestive
tract and body wall
 Coelom
= body cavity
lined with mesoderm
 Pseudocoelom = a body
cavity partially lined
with mesoderm
 Acoelomate = body
cavity not lined with
mesoderm
Patterns of Embryological Development
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Every animal starts as a zygote = fertilized egg
The zygote forms a blastula = hollow ball of cells
The first opening is called a blastopore
 Deuterostome
= blastopore becomes anus
 Protostome = blastopore becomes mouth
3 Layers of Gastrula
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1. ectoderm - outer layer of
skin, nervous tissue, sense
organs
2. endoderm - lining of
digestive tract, digestive and
respiratory system
3. mesoderm - skeleton,
muscles, excretory system
Segmentation and Cephalization
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Segmentation = repeated parts or
segments (ex. Worms)
Cephalization = concentration of
sense organs and nerve cells at the
anterior region (a HEAD)
Limb Formation – Segmented,
bilateral animals typically have
external appendages on both sides
of their bodies
Deuterostomes
chordates
echinoderms
arthropods
tardigrades
Ecdysozoa
roundworms
Protostomes
rotifers
mollusks
annelids
flatworms
Lophotrochozoa
Animals with a 3-layer embryo
cnidarians
sponges
placozoans
Animals with tissues
Animals
Fig. 25-7b, p. 407
Body Plans
Porifera: Sponges!!
The Anatomy of a Sponge
Section 26-2
Water flow
Osculum
Central cavity
Pores
Choanocyte
Spicule
Pore cell
Pore
Epidermal cell
Archaeocyte
Characteristics of Sponges
1.
2.
3.
4.
Simplest animals,
multi-cellular
No organs or
body system
Cellular digestion
Asymmetry
Characteristics of Sponges
5. Filter Feeders· Sessile (do
not move)
6.
Reproduce sexually (sperm
and eggs)
7.
Reproduce asexually
(regeneration)
8.
Skeleton composed of
spongin (soft) and spicules
(hard)
Sponge Anatomy
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Amebocytes - cells within the
sponge that move around supplying
nutrients and taking away waste
Collar cells
· layer of cells with flagella
· flagella keeps a water current
going in the sponge
· food vacuoles in the collar cells
digest plankton and other small
organisms (filter feeder)
Sponge Anatomy
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Oscula - large opening at
top of sponge, water exits
Pores - small openings at the
side, water enters
Sponge Reproduction and Dispersal
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Hermaphrodite
 Individual
that produces both eggs and sperm
 Sperm are released into water; eggs are retained
 Zygote develops into ciliated larva

Larva
 Free-living,
sexually immature stage in life cycle
 Settles and develops into adult
Cnidarians
Examples: Jellyfish, hydra, sea anemone, coral,
Portuguese man of war
Characteristics of Cnidarians
1. Tentacles
2. Cnidocytes (stinging
cells)
3. Nematocysts Stinging
organelles in tentacle cells,
triggered by contact, used
in feeding or defense
 (Portuguese Man of war
encounter)
General Cnidarian Features

4. Nerve net
 Simple
nervous system of interconnecting nerve cells
extending through the tissues
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5. Hydrostatic skeleton
 Fluid-filled
structure moved by contractile cells
Characteristics of Cnidarians
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Gastrovascular cavity
(digestion)
Most are radial
symmetry
Cnidarians have two body forms
Polyp - stationary,
vase-shaped
Examples: hydra,
coral, sea anemone
Medusa - swimming, cupshaped
Examples: jellyfish,
Portuguese man of war
Cnidarian Life Cycle
CORAL
-Live in areas of high levels of light
-Coral bleaching – occur when temperatures are too
high and kill the algae that live in the coral
Phylum Plathelminthes:
Flatworms: Planaria, tapeworm,fluke
Characteristics of Flatworms
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Flat bodies
Respiration: gases move
by diffusion through the
skin
bilateral symmetry
gastrovascular cavity
Characteristics of Flatworms
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some flatworms are
parasitic, some are free
living
they have anterior and
posterior ends exhibit
cephalization
Contain organ systems
acoelomates-no
coelem
25.6 Flatworms—Simple Organ
Systems
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Three main classes:
 Turbellarians
 flukes
– free living flatworms
(trematodes)
 tapeworms
(cestodes)
Turbellarians:
Structure of a Free-Living Flatworm
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Pharynx
 Muscular
tube connecting the
mouth with the gut
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Nerve cords
 Two
lines of communication
along length of body
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Ganglia
 Cluster
of nerve cell bodies
(simple brain)
Anatomy
Section 27-1
Eyespot
Ganglia
Head
Nerve
cords
Gastrovascular
cavity
Flatworms use a pharynx to suck
food into the gastrovascular
cavity. Digested food diffuses
from the cavity into other cells of
the body. Eyespots in some
species detect light.
Mouth
Excretory
system
Freshwater flatworms have
simple ganglia and nerve
cords that run the length of
the body. The excretory
system consists of a network
of tubules connected to flame
cells that remove excess
water and cell wastes.
Ovary
Testes
Pharynx
Most flatworms are
hermaphrodites, having male
reproductive organs (testes)
and female reproductive
organs (ovaries) in the same
organism.
Flame cell
Excretory
tubule
Flatworm Organ Systems
Planaria
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live in freshwater
mostly scavengers, also
feeds on Protists
Hermaphrodites
has a simple brain (ganglia)
and nervous system, plus 2
eyespots
they can regenerate
(regrow parts)
Tapeworms
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parasitic worms that live in the
digestive system
they have segmented bodies (each
segment is called a proglottid)
each proglottid is a hermaphroditic
reproductive organ
tapeworms can grow very long
(40-60 feet!)
attach to the intestine with hooks
and suckers on the head
do not have well developed
digestive systems
Beef Tapeworm Life Cycle
Flukes
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most have complex
life cycles involving
more than one host
Schistosoma (blood
fluke) spends part of
its life in a snail,
humans get infected
when they wade in
the water containing
the snails, the larva
then invade the
human's blood vessels
25.11 Roundworms—
Unsegmented Worms That Molt
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Roundworms (phylum Nematoda)
 Unsegmented
 secreted
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cuticle that is molted
Most are decomposers, some are parasites
 Parasitic
roundworms include Trichinella, Ascaris,
hookworms, Wuchereria, and pinworms
Phylum: Nematoda - Roundworms
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have a complete digestive tract (mouth and anus)
Psuedocoelem = a body cavity between endoderm
and mesoderm tissues (only partially lined with mesoderm)
More Roundworms: Trichinella
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-roundworms that
invade muscle tissue,
get by eating
undercooked pork
More Roundworms
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Vinegar eel - free living roundworm
Filarial worms-found in tropics (Asia) and
transmitted by mosquitoes and other insects.
Hookworms
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found in the soil and they burrow into skin
entering the blood stream to the lungs and
intestines.
Causes weakness and poor growth
¼ of the world’s population
25.7 Annelids—Segmented Worms
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Annelids
 bilateral
worms
coelom
 segmented body
 typically with chaetae (chitin reinforced bristles)

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Three main groups
 1)
marine worms (polychaetes)
 2) oligochaetes (including earthworms)
 3) leeches
Marine Polychaetes
Leeches – Bloodsuckers and Others

Leeches have a sucker at either end (1 mouth)
Oligochaetes
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Example: earthworms
 Exchange
gases across body surfaces
 Have five hearts and a closed circulatory system
 Nephridia regulate coelomic fluid
 Nervous system of ganglia and nerve cords
 Hydrostatic skeleton
 Hermaphroditic
Earthworm circulation
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Earthworms have a CLOSED CIRCULATORY SYSTEM
Blood is enclosed in two main vessels - the dorsal and
ventral blood vessels. The heart consists of five arches
in the anterior end of the worm - called the AORTIC
ARCHES
Earthworm Body Plan
How Earthworms Move
25.8 Mollusks—Animals With a Mantle

Mollusks (phylum Mollusca)
 Bilaterally
symmetrical with a reduced coelom
 Mantle covers internal organs, secretes a shell
 Feed using a hard radula (tongue-like organ)
 Have a complete digestive tract
 Gills for respiration in aquatic species
Shell
Mantle cavity
Foot
Gills
Digestive tract
Mollusk Diversity
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Chitons
Eight overlapping plates
 Scrape algae with radula
 No cephalization
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Gastropods (snails, slugs)
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Bivalves (mussels, clams, oysters)
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Undergo torsion during development
Hinged, two-part shell
Cephalopods (squids, octopuses)

Large, fast and smart; closed circulatory system
Gastropod “belly foot” Body Plan
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60,000 species
Only terrestrial
mollusks
Torsion =
rearrangement of
body parts during
development
Variations on the Gastropod Body Plan
Bivalve Body Plan: Clam
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Hinged 2-part shell
25.9 Cephalopods—Fast and Brainy
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Cephalopod (“head foot”)
 Tentacles
attached to the head are evolutionary
modifications of the foot; they surround the mouth, which
has a hard, horny beak

Include the fastest (squids), biggest (giant squid), and
smartest (octopuses) invertebrates
 Jet
propulsion, complex eyes, closed circulatory system,
complex behavior
Cephalopods
25.12 Arthropods—
Animals With Jointed Legs

Arthropods
(phylum
Arthropoda) are
the most diverse
animal phylum –
with more than a
million species


Trilobites are an
extinct group
Modern arthropods
include horseshoe
crabs, spiders, ticks,
crabs, lobsters,
centipedes, and
insects
Arthropod means "jointed foot"
Living Arthropod Subgroups
Segmentation
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More obvious in
larval forms,
adults have fused
segments → Head |
Thorax | Abdomen
Some have a fused
head and thorax -the cephalothorax
Exoskeleton
1.
2.
made of chitin
for protection &
support
shed during
molting
Compound eyes
Open
Circulatory
System
Respiration
Excretory structures called Malpighian
tubules
25.14 The Mostly Marine Crustaceans

Crustaceans are mostly marine arthropods with two
pairs of antennae
Subphylum: Crustacea
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1.

Marine members
include shrimp,
lobster, barnacles, &
crabs
Terrestrial
crustaceans called
isopods (pillbugs or
rollypollys)
Freshwater members
include crayfish and
daphnia
Characteristics
1.
2.
3.
4.
5.
6.
All have mandibles for
chewing or tearing
Have cephalothorax &
abdomen
Lobsters and large
custraceans are called
Decapods
Barnacles are sessile
(don't move)
Have 10 pairs of jointed
appendages
Breathe through gills
Subphylum: Chelicerata
Includes (Class
Arachnida)
spiders, ticks,
scorpions, mites
and horseshoe
crabs
25.13 Chelicerates—
Spiders and Their Relatives

Chelicerates are arthropods
without antennae
 Marine
chelicerates include
the oldest living arthropod
lineage (horseshoe crabs)
 All land chelicerates are
arachnids, including spiders,
scorpions, ticks, and mites
Subphylum: Chelicerata
1.
2.
3.
4.
Have a cephalothorax (fused
head & thorax) and abdomen
No antenna
Spinnerets in spiders make
webs
Have 6 pairs of jointed
appendages:
* Chelicerae - claws or
fangs (1 pair) - (spiders have
venom)
* Pedipalps - used for
feeding, sensing, transferring
sperm (1 pair)
* Walking legs - movement
(4 pairs)
Chelicerates: The Spiders
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Spiders bite with fanglike chelicerae that deliver
venom from poison glands
Paired spinners in the abdomen eject silk
Open circulatory system mingles blood with tissue
fluids; Malpighian tubules move excess water and
wastes to gut for disposal
Subphylum Uniramia - Insects and their
Relatives
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Includes 3 classes
Chilopoda (centipedes)
Diplopoda (millipedes)
Insecta
Class Chilopoda: Centipedes
1.
2.
3.
4.
5.
Name means "100
legs"
Flattened body
Have 1 pair of legs
per body segment
Pincers can inject
venom
Predators
Class Diplopoda: Millipedes
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Name means "1000
legs"
Have 2 pairs of legs
per body segment
Rounded body
Scavengers or
herbivores
Class Insecta
25.16 The Insects

Insects have a three-part body plan
 The
head has compound eyes, a pair of antennae, and
specialized mouthparts
 The thorax has three pairs of legs; some lineages have wings
 Malpighian tubules in the abdomen eliminate wastes and
save water
Class Insecta
1.
2.
3.
4.
5.
6.
3 pairs of legs
3 body parts - head,
thorax, abdomen
Wings in most
All appendages attach to
the thorax
9-11 segments in
abdomen
Mandibles for chewing
Insects
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Arthropods are the most
successful animals, and insects
are the most successful
arthropods
Insects are adapted to life on
land; a system of tracheal
tubes delivers air to their
tissues
Development may be direct,
or through incomplete or
complete metamorphosis
Insect Development
Social Insects
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Queen: Lays eggs (1
queen per hive)
Drones: a few males to
fertilize eggs
Workers: all infertile
females
Nature: Silence of the Bees: Inside the hive:
http://www.youtube.com/watch?v=lE8QuBDkkw
Bee dance
http://www.youtube.com/watch?v=7m5vt07W2
n4
Bee dance:
http://www.youtube.com/watch?v=4NtegAOQp
Ss&NR=1
Colony Collapse Disorder
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Nature: Silence of the Bees:
http://www.youtube.com/watch?v=xHZ4ThOH70w
60 Minutes: Why are the honey bees disappearing?
Part 1
http://www.youtube.com/watch?v=VRBJf57aNp4
Part 2
http://www.youtube.com/watch?v=_RZv9BvQJ-A
The Protostome-Deuterostome Split
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So far, all of the animals with a three-layered
embryo – from flatworms to arthropods – have
been protostomes
All of the following animals – from echinoderms to
vertebrates – are deuterostomes
25.18 The Spiny-Skinned Echinoderms
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Have“spiny skins” embedded with interlocking spines
and plates of calcium carbonate
Begin life as bilateral larvae and develop into spinyskinned, radial adults
They are brainless and have a unique water-vascular
system for locomotion
Echinoderm Diversity
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Include about 6,000 marine invertebrates
Echinoderms can regenerate lost body parts

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any portion of a sea star with some of the central disc
can regrow missing parts
Respiration – gas exchange occur by diffusion
across the tube feet
No specialized excretory organs
Separate sexes with external fertilization
Phylum Echinodermata

Includes 5 classes:
* sea urchins & sand dollars
* brittle stars
* sea cucumbers
* starfish (sea star)
* sea lilies & feather stars
Sea Urchins:

* Spherical shape
* Live on ocean bottom
* Scrape algae to feed
* Long, barbed spines
make venom for
protection
Sand Dollars
•
•
•
•
Flattened body
Live in sand along
coastlines
Shallow burrowers
Have short spines
BRITTLE STARS
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Live on the ocean bottom
beneath stones, in crevices,
or in holes
Have long, narrow arms
Arms readily break off &
regenerate
Move quicker than starfish
Feed by raking in food
with arms or trapping it
with its tube feet
SEA CUCUMBER
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Lack arms
Shaped like a pickle or cucumber
Live on ocean bottoms hiding in caves during the day
Have a soft body with a tough, leathery outer skin
Five rows of tube feet run lengthwise on the top surface of
the body
Have a fringe of tentacles (modified tube feet) surrounding
the mouth to sweep in food & water
Tentacles have sticky ends to collect plankton
Show bilateral symmetry
Can eject parts of their internal organs (evisceration) to scare
predators; regenerate these structures in days
Be sure to pay attention to the video and sea cucumber
excretion
Echinoderm Body Plan: Sea Star
STARFISH
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Usually sedentary along
shorelines
Prey on bivalve mollusks
such as clams & oysters
Have 5 arms that can be
regenerated
Arms project from the
central disk
Mouth on (underside)
SEA LILIES AND FEATHER STARS
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Sessile
Have a long stalk with
branching arms that attach
them to rocks & the ocean
bottom
Can detach & move around
Mouth & anus on upper
surface
May have 5 to 200 arms with
sticky tube feet to help
capture food (filter feeders) &
take in oxygen
Common in areas with strong
currents & usually nocturnal
feeders
Can you believe this PowerPoint is 100 slides??????