1. Lecture 20: Comparative anatomy
What do animals do to survive?
have
are
carry out
with
such as
All Animals
Feeding
Respiration
Circulation
Excretion
Response
Movement
Reproduction
Eukaryotic cells
Heterotrophs
Essential functions
No cell walls

2. Invertebrate feeding and digestion:
Invertebrates can either have intracellular or extracellular digestion:
Intracellular meaning that food is digested within each individual cell of the organism.
Examples: Sponges
Extracellular means that digestion occurs inside a digestive tract or cavity, then absorbed into the body.
Examples: mollusks, chordates, arthropods, echinoderms

3. Stomach and digestive glands
Invertebrate digestive systems:
Section 29-2
Arthropoda
Annelida
Flatworm
Coelenterata
Mouth/anus
Mouth
Gastrovascular cavity
Pharynx
Crop
Gizzard
Intestine
Rectum
Anus
Stomach and digestive glands

4. Vertebrate digestive systems:
The digestive systems of many vertebrates have organs that are well adapted for different feeding habits.
Carnivores, such as sharks have short digestive tracts that produce fast-acting digestive enzymes.
Herbivores have long intestines that have large colonies of bacteria that help in digesting the cellulose fibers in plant tissues.

5. The Digestive Systems of Vertebrates
Section 33-3
Esophagus
Stomach
Intestine
Liver
Gallbladder
Pancreas
Cloaca
Crop
Gizzard
Cecum
Rectum
Shark
Salamander
Lizard
Pigeon
Cow

6. Aquatic invertebrates:
Respiration in animals:
Aquatic invertebrates:
Aquatic animals have natural moist respiratory surfaces. some respire through diffusion through their skin and others use gills.
Terrestrial Invertebrates:
There are many different respiratory specialized organs in terrestrial invertebrates.
Spiders use parallel book lungs.
Insects use openings called spiracles where air enters the body and passes through tracheal tubes for gas exchange.
Snails have a mantel cavity that is lined with moist tissue and an extensive surface area of blood vessels.

7. Invertebrate respiratory systems:
Mollusk
Insect
Spider
Gill
Siphons
Movement of water
Book lung
Airflow
Tracheal tubes
Spiracles

8. Vertebrate respiratory systems:
Chordates have one of two basic structures for respiration:
Gills – for aquatic chordates.
Example: fish and amphibians.
Lungs - for terrestrial chordates.
Examples: adult amphibians, reptiles, birds, and mammals.

9. Vertebrate Gills: Vertebrate Lungs:
Water flows through the mouth then over the gills where oxygen is removed.
Carbon dioxide and water are then pumped out through the operculum.
Vertebrate Lungs:
Salamander
Lizard
Pigeon
Primate
Nostrils, mouth, and throat
Trachea
Lung
Air sac

10. Open circulatory systems:
Invertebrate circulatory systems:
Invertebrate circulatory system can range from a system where cells simply do diffusion to take in oxygen or systems with many hearts and even systems with one heart.
Open circulatory systems:
The blood is pumped through open cavities.
This system is found in arthropods and mollusks.
Closed circulatory systems:
A closed system forces blood through vessels that extend throughout the body of the organism. Since the system is “closed” the blood never leaves the vessels.
This system is found in Annelids and chordates.

11. Invertebrate Circulatory Systems:
Section 29-2
Invertebrate Circulatory Systems:
Heart like structures
Blood vessels
Heart like structure
Small vessels in tissues
Hearts
Heart
Sinuses and organs
Insect: Open Circulatory System
Annelid: Closed Circulatory System

12. Vertebrate circulatory systems:
Chordate circulatory systems range from a single loop system (found in organisms with gills) to double loop systems.
Single-Loop Circulatory System
Double-Loop Circulatory System
Fishes
Most Reptiles
Crocodilians, Birds, and Mammals

13. Aquatic Invertebrate excretion:
Some aquatic invertebrates diffuse ammonia out their bodies into the surrounding water where it is diluted and carried away.
Example: sponges, coelenterate, and some round worms.
Other aquatic invertebrates swell up with water, dilute the wastes and excrete the wastes through tiny pores in their skin.
Terrestrial Invertebrate excretion:
Many terrestrial invertebrates convert ammonia into urea.
Urea is a simpler nitrogenous compound that is much less toxic than ammonia.
This urea is eliminated from the body in urine.

14. Invertebrate Excretory Systems
Section 29-2
Annelid
Arthropod
Flatworm
Malpighian tubules
Digestive tract
Nephridia
Excretory pore
Excretory tubule
Flame cell
Flame cells
Excretory tubules

15. Vertebrate Excretion:
Aquatic vertebrates kidneys and rely on gill slits to release excretory wastes into surrounding water for dilution
Terrestrial vertebrates rely on the kidney’s to filter out the ammonia and change it into urea and send it to be released in urine.

16. Nervous system
All animals respond to their environment through specialized cells called nerve cells.
In most animals, nerve cells hook together to form the nervous system.
Nervous systems can range from fairly simple to extremely complex.
The arrangement of nerve cells from phylum to phylum can be dramatically different.

17. Invertebrate Nervous Systems
Section 29-2
Ganglia
Brain
Arthropod
Mollusk
Flatworm