What is an Invertebrate?
What is an Invertebrate?
• Internal skeleton is not unique to
vertebrates. (Starfish has an internal
skeleton)
What is an Invertebrate?
• Internal skeleton is not unique to
vertebrates. (Starfish has an internal
skeleton)
• Vertebrate animals: the brain is encased
in a bony skull.
What is an Invertebrate?
• Internal skeleton is not unique to
vertebrates. (Starfish has an internal
skeleton)
• Vertebrate animals: the brain is encased
in a bony skull.
• Nervous system of true invertebrates are
different from true vertebrates.
Characteristics of Invertebrates
Characteristics of Invertebrates
• Locomotion and Support.
Characteristics of Invertebrates
• Locomotion and Support.
• Muscles and Skeletons.
Characteristics of Invertebrates
• Locomotion and Support.
• Muscles and Skeletons.
• Feeding mechanisms.
Characteristics of Invertebrates
•
•
•
•
Locomotion and Support.
Muscles and Skeletons.
Feeding mechanisms.
Excretion and Osmoregulation.
Characteristics of Invertebrates
•
•
•
•
•
Locomotion and Support.
Muscles and Skeletons.
Feeding mechanisms.
Excretion and Osmoregulation.
Circulation and Gas Exchange.
Characteristics of Invertebrates
•
•
•
•
•
•
Locomotion and Support.
Muscles and Skeletons.
Feeding mechanisms.
Excretion and Osmoregulation.
Circulation and Gas Exchange.
Nervous System and Sense Organs.
Locomotion and Support
(Protozoa and Metazoa)
• Four fundamental locomotor patterns.
I. Ameboid movement.
II. Ciliary and flagellar movement.
III. Hydrostatic propulsion.
IV. Locomotor limb movement.
I. Ameboid movement.
• Ameboid locomotion is used by certain protists
and by numerous kinds of ameboid cells that
are located within the bodies of most Metazoa.
Complex changes in cell
fine structure, chemistry,
and behavior.
(gel-like)
(more fluid)
Mechanisms of Ameboid movement.
Mechanisms of Ameboid movement.
HELIOZOANS ACTINOPHRYS SP. I COLLECTED THIS
ONE IN WISCONSIN.
Axopodia
Ameboid
locomotion
used for body
maintenance
II. Ciliary and flagellar movement.
• Cilia and/or flagella occur in every
animal phylum with the exception of the
Arthropods.
Figure 3.7 Cilia and Flagella anatomy!
Figure 3.7 Cilia and Flagella anatomy!
This is the 9 + 2 pattern characteristic of
nearly all flagella and cilia.
Cilia move in waves: metachronal waves. Usually many.
Undulatory
movement
Power
stroke or
oar like
action
Usually few.
Overlap of microtubular and fibrous
kinetosomes that provide a structural lattice.
Cilia architecture variation.
Cilia
architecture
variation.
Cilia and
flagella
used for
feeding
Comb Jellies Phylum Ctenophora are the
larges animals known to rely primarily on cilia
for locomotion.
Macrocilia
III. Hydrostatic propulsion.
• Based on two fundamental properties of
liquids: their incompressibility and their
ability to assume any shape.
• Limitation of muscles: They can only
perform work by contracting.
Sipunculan worm.
Sipunculan worm.
Sipunculan worm.
Peristalsis
Tube-within-a-tube
Pseudocoelomates Coelomates
Phylum Annelida, Class Polychaeta
Phylum Annelida, Class Polychaeta
Phylum Echinodermata: Oreaster reticulatus
Family Oreasteridae
Tube foot from an echinoderm, ampulla,
radial canal, lateral canal, podium are shown.
Phylum Echinodermata: Astichopus multifidus Family Stichopodidae
IV. Locomotor limb movement.
• Rigid skeleton.
• Muscles.
Rigid skeleton.
• Endoskeleton: Derived from mesoderm.
• Exoskeleton: Derived from ectoderm.
----Both have organic and inorganic
components.
Most skeletons act as body elements against
which muscles operate by which muscle
action is converted to body movement.
Muscles.
• Animals that possess rigid but articulate
skeletons have antagonistic muscles often
appearing in pairs (flexors and
extensors).
Protractors and retractors;
adductors and abductors.
The Big Picture
The four fundamental locomotor patterns and the
three skeletal systems define how invertebrates
function.
Locomotor patterns of invertebrates can be divided into
ameboid movement, ciliary and flagellar movement,
hydrostatic propulsion, and locomotor limb movement.
Skeletal systems of invertebrates can be divided into
hydrostatic skeletons, endoskeletons, and exoskeletons.
Each of these categories have numerous variation.