Transcript Tuesday January 25, 2005 BIOL L100 Indiana University Southeast

Invertebrates
1
Animal Characteristics

All organisms in this kingdom have
these common characteristics:
 Multicellular Eukaryotes
 No cell wall- unlike fungi, plants,
bacteria
 Heterotrophs– consumer not
decomposer
 Have Specialized Cells- unlike
protists
2
Needs of Animals



Need: Sense and chase down food source
Adaptation: nervous / motor systems
Need: Break up food and absorb nutrients
Adaptation: digestive system
Need: Deliver oxygen to all cells
Adaptation: circulatory / respiratory
systems
3
SYMMETRY



Asymmetry – no symmetry
Radial symmetry - can cut in equal
halves-more than one way
Bilateral symmetry – allows for
development of brain region in a central
location (head)
4
Types of Symmetry
Asymmetry
5
Asymmetry-Sponges Only
6
Radial Symmetry
7
Background: different types of body
symmetry
*Usually simpler
organisms
*Usually more
complicated organisms
8
Bilateral Symmetry
They all have a head
area with sense organs
9
Development of Organisms





Develop from a single cell, the zygote
Mitosis forms new cell in a process called
cleavage
A hollow ball of cells are formed called a blastula
Gastrulation is the folding in of the blastula to
form two layers
These two layers are the ectoderm and the
endoderm
10
Development
11
Development




Ectoderm develops into skin and nervous tissue
Endoderm develops into the lining of the
digestive tract and organs associated with
digestion
In some animals the gastrula forms a mesoderm
Mesoderm is the third layer and develops into
muscles, circulatory, excretory, and respiratory
systems
12
Development


Protostome is an animal with a mouth that
develops from the opening in the gastrula
called the blastopore
Deuterostome The anus develops from the
opening in the gastrula
13
Body Plans



Acoelom- do not have a body cavity,
organs are imbedded in tissues
Pseudocoelom -(partial) a body cavity
partly lined with mesoderm
Coelom- a body cavity that provides space
for the development of internal organs
(something for muscles to push against to
move)
14
*Background: types of coelomes (body cavities)
15
Vertebrate vs Invertebrate

Vertebrate- has a backbone

Invertebrate- has NO backbone
16
Exoskeleton


Functions:
1. Protection
2. Prevents water loss on land
(waxy layer)
Problems:
1. Heavy
2. Growth requires molting
17
Exoskeletons
18
Endoskeleton


An internal skeleton that provides
support inside the body
Advantage: Organisms can grow
larger with skeleton inside
19
Endoskeletons
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Sponges


Simplest Animals
Asymmetry
21
Sponges

Sessile - do not move

Asymmetrical

No tissue (Only organized cells)
22
Sponges

Oxygen and food come in through
Diffusion

Filter Feeds as an adult
23
Sponge Reproduction


Sexual – release sperm into water
(external fertilization very common in
aquatic animals)
Hermaphroditism – sponges have sperm
AND eggs to increase the odds of
reproduction

Offspring can swim to a new location

Asexual fragmentation also possible
24
Cnidarians
Sea Anemone
(Polyp)
Jellyfish
(Medusa)
25
Cnidarians


Evolution of Radial
Symmetry
Extends tentacles equally in
all directions
(increase food uptake)
26
Cnidarian Characteristics



Basic digestive system
Also basic nervous system (nerve net)
O2 still enters by diffusion
27
Cnidarian Characteristics

Reproduces sexually and asexually

Skeleton-none present, but dead coral
remains are calcium carbonate
28
Body Plans of Cnidarians
29
Flatworms-Platyhelminthes
Planarian – not
parasitic
Tapeworm – parasitic
30
Flatworm Characteristics

No coelom – Why? Many are parasitic

O2 and sugar are absorbed in host’s intestine

Bilateral symmetry

Reproduction-most are hermaphrodites
31
Tapeworms
32
Tapeworm Life Cycle
33
Flatworm or Planaria
S
e
e
f
u
l
l
s
i
z
e
i
m
a
g
e
.
Fresh Water Planaria
Uses Pharynx to obtain food
Salt Water Flatworms
34
Sheep Liver Fluke
35
Roundworms
hookworm - parasitic
36
Roundworms

Smooth, non-segmented body

Pseudocoelom (moves more)


Can burrow through skin (walking around
barefoot)
Also enters through contaminated food
37
Roundworm Characteristics
More Advanced


Bilateral symmetry
Complete digestive system with mouth
and anus

Sexual reproduction

Oxygen enters by diffusion
38
Hookworms,
Pinworms,
Tapeworms that
were removed from a
Brazilian boy treated
on a Rockefeller
foundation mission
(early 1900’s)
These parasites still
affect people all over
the globe.
39
Not a problem in U.S.
40
Why not?

Food safety inspections

Good sanitation

Medication widely available
41
Roundworms
Dirofilaria is a
roundworm
that causes
heartworm
disease in dogs.
42
Ascaris: a
parasitic
roundworm
Other Roundworms
43
Other Roundworms
Elephantiasis results
when a roundworm
blocks the lymphatic
system, causing severe
swelling
The roundworm
is carried by
mosquitoes in
tropical Africa
44
Roundworms: Hookworms
Hookworms attached to
the intestines
45
Segmented Worms
leech
Earthworm
46
Segmented Worm
Characteristics

Bilateral symmetry

Full Coelom (full range of
motion, complex organs inside)

Complete digestion system

Most are hermaphrodites with
sexual reproduction
47
Segmented Worm
Characteristics


Gets O2 directly from moist skin,
 closed circulatory system with hearts to
deliver
Food – blood (leeches), or dirt
(earthworms)
48
Earthworms
Giant Earthworm
Regular Earthworm
49
Earthworms



Swallow dirt, filter out food
Loosen soil, helps to aerate soil
for plants
Also fertilizes plants with
castings (poop)
50
Leeches

Two chemicals in saliva to
help it take blood from hosts
1.
2.
Anesthetic (blocks pain)
Anti-coagulant (prevents
blood clotting)
51
Mollusks
Snail – 1 shell
Squid – no shell
Clam – 2 shells
52
These are all in the same group!?!
inside of a clam
53
Mollusk Characteristics

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Bilateral symmetry
Getting food – filter feeders (clams),
grazers (snails), predators (slugs)
Getting O2 – gills in aquatic mollusks,
primitive lung in snails
Open or closed circulatory system
54
Open vs. Closed Circulatory
System
Open
Closed
•No blood vessels
•Blood in vessels
•Blood surrounds body’s organs,
delivers O2
•Larger animals
•Smaller animals
55
Mollusk Reproduction

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
Hermaphrodites (both mollusks and
segmented worms)
Aquatic – release sperm and eggs
into water
Land – meet and swap sperm,
fertilize eggs inside
56
Chambered Nautilus
57
Arthropods

Four main classes within this HUGE
phylum:
1.
Arachnids
2.
Crustaceans
3.
Centipedes / millipedes
4.
Insects
58
Arachnids
Chigger (flea)
Black widow
Brown recluse
Scorpion
Tick
59
Crustaceans
Crab
Lobster
Barnacles
60
Many-footed ones
Centipede
Millipede
61
Insects
Wasp
Fire ants
Grasshopper
62
Arthropod Characteristics

Most successful of all animal phyla

Coelom

Bilateral symmetry

Segmented body

Exoskeleton- NOT the same as mollusk
63
shell
Arthropod Characteristics
•Oxygen enters by spiracles and then
into tracheal tubes in some arthropods.
Book lungs in spiders.
• Reproduction- Internal fertilization
(mating) in land arthropods and
External fertilization in sea arthropods
64
Arthropod Characteristics



Open circulatory system
Uses special jaws called
mandibles
Use Pheromones (chemical
signals) for communication and
mating
65
Arthropods:
Complex Nervous System
Sophisticated sensory / motor control
Compound eye of a fruit fly
66
Metamorphosis
67
Echinoderms
sea urchin
sea star
sea
cucumber
68
Echinoderm Characteristics


Bilateral symmetry in larvae
Radial symmetry in adults
(live on ocean floor)

Coelom

Endoskeleton

Deuterostomes
69
Echinoderm Characteristics


Food – variety of diet (some eat clams,
some eat algae, some filter feed)
Water vascular system (water instead of
blood to carry O2)

Reproduction typical in water

Regeneration possible in some
70
Chordates
71
All Chordates



Have notochord – precursor to vertebral
spinal column (semirigid, filled with fluid)
Vertebrates replace this with a full spinal
cord
Some chordates are invertebrates still
72
Chordates

Chordates have 3 subphylums


Tunicates
Lanceletes
 Vertebrates
73
Invertebrate Chordates
lancelet
tunicate
74
Each of these is a Class in the
Phylum Chordata
75