Exo, Endo, Hydro, No You Decide!
Post-Lab
Endoskeleton
• Endo = within
• Endoskeleton = internal skeleton
• Movement = muscles pull on bones (via
tendons)
• Most organisms with an internal skeleton are
vertebrates
• A vertebrate is an organism that has a
backbone that protects a spinal cord (bundle
of nerves from brain)
Exoskeleton
• Exo = out of, outer
• Exoskeleton = External skeleton
• Movement = Muscles pull on external
shells
• Organisms with an exoskeleton are
invertebrates
• Arthropods = Chitin exterior
• Molluscs = Calcium carbonate exterior
Hydrostatic
Skeleton
• Hydro = water
• Static = stationary, fixed
• Hydrostatic skeleton = water stationary
skeleton (essentially sacs of water that
because of the high pressure act like bones)
• Muscles pull against water filled
compartments
• Invertebrates
Earthworm
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• Hydrostatic Skeleton
• Movement - Muscles
pull on fluid-filled
compartments
• Protection - Soil and
surroundings
• Fact - Earthworms don’t
have lungs! They
breathe through their
skin!
Horseshoe Crab
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• Exoskeleton
• Movement - Muscles
pull on covering from
the inside
• Protection - Shell is
made of chitin
• Fact - Have been on
Earth since well before
the dinosaurs!
• Fact - Have ten eyes
and can see UV light!
Jellyfish
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• No skeleton
• Movement - Body Parts
pull against water in the
environment (mainly
they drift on ocean
current)
• Protection - Stinging
cells/move away
• Fact - Lion’s Mane
Jellyfish can grow to be
120 feet long!
Salamander
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• Endoskeleton
• Muscles pull on bones
• Move to
cover/camouflage
• Fact - Salamander
refers to an entire group
of amphibians that have
tails as adults!
• Fact - All salamanders
are carnivores!
Leech
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• Hydrostatic Skeleton
• Movement - Muscles pull on
fluid-filled compartments
• Protection - Move to cover/
camouflage
• Fact - Some leeches eat
decaying plant material,
some are predators, and
others are parasites living off
of the blood and tissues of
other organisms
• Fact - Doctors use leeches
to help restore blood
circulation to reattached
fingers and toes!
Lobster
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• Exoskeleton
• Movement - Muscles
pull on covering from
the inside
• Protection - Chitin,
claws, and selfamputation
• Fact - Lobster blood is
clear!
• Fact - Lobsters can
regenerate claws,
antennae, and legs!
Mussel
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• Exoskeleton
• Movement - Muscles pull on
covering from the inside
• Protection - Shell is made of
calcium carbonate
• Fact - Biggest enemy is the
dog whelk which bores a
hole through shell and sucks
out meat!
• Fact - Male meat is a pale
white color, female meat is
has an orange shade!
Seahorse
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• Endoskeleton
• Movement - Muscles
pull on bones
• Protection - Spiny
skin/move to
hide/camouflouge
• Fact - Seahorses are a
type of fish!
• Fact - Seahorses have
a single mate for life!
Shark
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• Endoskeleton (bones are
made of cartilage)
• Muscles pull on bones
• Protection - Teeth/Move
away
• Fact - Sharks can smell
one drop of blood in one
million drops of water!
• Fact - Of the 368 species
of sharks, only 25 have
been reported to attack
humans.
Turtle
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• Endoskeleton and
exoskeleton
• Movement - Muscles pull
on bones
• Protection - Shell
(Keratin), draw back into
exoskeleton
• Fact - Several species of
turtle can live to be over
100 years old!
• Fact - The turtle shell is
made of 60 bones
connected together!
Cricket
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• Exoskeleton
• Movement - Muscles pull
on covering from the
inside
• Protection - Chitin
shell/move away
• Fact - Compound eyes
allow them to see in
several directions
simultaneously
• Fact - Although they have
wings, many don’t fly
Sea Star
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• Endoskeleton (no movable
bones) and hydrostatic
skeleton
• Movement - tube feet
controlled by water pressure
• Protection - Spiny outer
covering/ spontaneous
amputation
• Fact - While they do have an
endoskeleton, they are
invertebrates!
• Fact - Once called starfish…
now called sea star because
they are not fish.