Characteristics of Invertebrates
•
•
•
•
Feeding mechanisms.
Excretion and Osmoregulation.
Circulation and Gas Exchange.
Nervous System.
Feeding mechanisms.
(Protozoa and Metazoa)
• Heterotrophic: ingest organic material.
Feeding mechanisms.
(Protozoa and Metazoa)
• Heterotrophic: ingest organic material.
I. Intracellular digestion-within a
cell: Endocytosis (phagocytosis
and pinocytosis)
Feeding mechanisms.
(Protozoa and Metazoa)
• Heterotrophic: ingest organic material.
I. Intracellular digestion-within a
cell: Endocytosis (phagocytosis
and pinocytosis)
II. Extracorporeal digestion-outside
the body.
Feeding mechanisms.
(Protozoa and Metazoa)
• Heterotrophic: ingest organic material.
I. Intracellular digestion-within a
cell: Endocytosis (phagocytosis
and pinocytosis)
II. Extracorporeal digestion-outside
the body.
III. Extracellular digestion-in a gut.
Protista Phylum Ciliophora
Phagocytosis Fig. 3.12
Pinocytosis Fig. 3.12
Phylum Mollusca: Class Bivalvia
Suspension Feeding
Phylum Mollusca: Class Bivalvia
Phylum Echinodermata, Class Echinoidea
Tube Feet Suspension Feeding
Phylum Platyhelminthes, Class Turbellaria
Carnivore
Phylum Annelida
Class Polychaeta
Deposit Feeding
Phylum Annelida
Class Polychaeta
Excretion and Osmoregulation.
Excretion and Osmoregulation.
• Excretion is the elimination from the body of
metabolic waste.
Excretion and Osmoregulation.
• Excretion is the elimination from the body of
metabolic waste.
• Osmoregulation is the regulation of water and
ion balance within the body fluids.
Excretion and Osmoregulation.
• Excretion is the elimination from the body of
metabolic waste.
• Osmoregulation is the regulation of water and
ion balance within the body fluids.
• Both vary depending on environment of
invertebrates.
Nitrogenous Wastes and Water
Conservation (Figure 3.21 A)
H2O
H2O
Salt
Salt
Marine (isotonic
environment): Organism
is isotonic and waste is
released as ammonia.
Nitrogenous Wastes and Water
Conservation (Figure 3.21 B)
Fresh water (hypotonic
environment): Organism is
hypertonic and waste is
released as ammonia.
H2O
Salt
Nitrogenous Wastes and Water
Conservation (Figure 3.21 C)
Terrestrial (“dry environment):
Organisms is hypotonic and
waste is released as uric acid.
H2O
Salt (in
solution)
Excretory and Osmoregulatory
Structures
Related to surface-to-volume ratio, and
animals bauplan.
1. Contractile vacuoles and water expulsion
vesicles (WEV).
Excretory and Osmoregulatory
Structures
Related to surface-to-volume ratio, and
animals bauplan.
1. Contractile vacuoles and water expulsion
vesicles (WEV).
2. Nephridia (Protonephridia and
Metanephridia).
Circulation and Gas Exchange
• The transport of materials from one
place to another depends on the
movement and diffusion of substances in
body fluids.
Fig. 3.24
Utilize water from the environment as a
circulatory fluid.
Fig. 3.24
Pseudocoelom
Pseudocelomates use fluids in the body cavity for
circulation.
Fig. 3.24
Closed circulatory
system (annelids)
Open circulatory
system (arthropods)
Gas Exchange and Transport
Outside
Inside
Fig. 3.26
External modifications
to increase surface area
to volume ratio
Nervous System and Sense Organs.
Ventral Nerve Cord
SEM of cross sections of a Nematomorph
The Big Picture
The size and bauplan of invertebrates determines the
type of excretory, osmoregulatory, circulatory, gas
exchange, and nervous system.
The diversity comes from the constraints placed on
the particulate invertebrate group due to its bauplan.