Animal Kingdom:Comparative Anatomy

A.Collins

JSHS

Pre-AP Biology

Animal Types

All animals are grouped as either an invertebrate or a vertebrate. 95% of all animals are invertebrate

organisms. The animals do not have a backbone or

vertebral column. 5% of all animals are vertebrates.

These animals do have a backbone.

Section 26-1

have are carry out

with such as

What do animals do to survive? Concept Map

AllAnimals

Feeding Respiration Circulation Excretion Response Movement Reproduction

Eukaryoticcells Heterotrophs Essential

functions

No cell walls

Feeding

Most animals do not absorb food; instead they ingest it.

Animals range from filter feeder and herbivores to carnivores and from commensalites to parasites.

All animals have developed different mouth structures and different digestive systems based on food and environmental adaptations.

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, worms, arthropods, echinoderms

Section 29-2

Arthropod

Annelid

Flatworm

Cnidarian

Mouth/anus

Mouth/anusMouth

Mouth

Gastrovascularcavity

Gastrovascularcavity

Pharynx

Pharynx

PharynxCrop

Crop

Gizzard

Intestine

Intestine

Rectum

Anus

Anus

Stomachand

digestive glands

Figure 29–8 Invertebrate Digestive Systems

Mammalian Teeth

Incisors – cut food Canine – pointed to stab, hold, tear

food Molars and pre-molars – flat

surfaces to grind and chew food

Section 32-1

CARNIVORE HERBIVORE

Molars crush and grind food. The ridged shape of the wolf’s molars and premolarsallows them to interlock during chewing, like the blades of scissors. The broad,flattened molars and premolars of horses are adapted for grinding tough plants.

Chisel-like incisors are used forcutting, gnawing, and grooming.

Canines are pointed teeth. Carnivoresuse them for piercing, gripping, and tearing.In herbivores, they are reduced or absent.

Jaw jointJawjoint

WolfHorse

Figure 32–4 The Jaws and Teeth of Mammals

Digestion

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.

Section 33-3

Esophagus

Stomach

Intestine

Liver

Gallbladder

Pancreas

Cloaca

Crop

Gizzard

Cecum

Rectum

Shark Salamander Lizard Pigeon Cow

Figure 33–8: The Digestive Systems of Vertebrates

Respiration in animals

Whether they live in water or on land, all animals must respire. To respire means to take in oxygen and give off

carbon dioxide. Some animals rely of simple diffusion

through their skin to respire. While others… Have developed large complex organ

systems for respiration.

Invertebrate respiration

Invertebrate respiratory organs have large surface areas Are in contact with air or water If require diffusion they must be moist.

Aquatic invertebrates

Aquatic animals have natural moist respiratory surfaces, and some respire through diffusion through their skin. Example: jellyfish and anemones

Some larger aquatic animals like worms and annelids exchange oxygen and carbon dioxide through gills. Gills are organs that have lots of blood vessels

that bring blood close to the surface for gas exchange.

Terrestrial Invertebrates

Terrestrial invertebrates have respiratory surfaces covered with water or mucus. (This reduces water loss)

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 a network of tracheal tubes for gas exchange

Snails have a mantel cavity that is lined with moist tissue and an extensive surface area of blood vessels.

Section 29-2

MolluskInsect

Spider

Gill

Siphons

Movement of water

Booklung

Airflow

Trachealtubes

Spiracles

Figure 29–9 Invertebrate Respiratory Systems

Vertebrate respiratory systems

Chordates have one of two basic structures for respiration: Gills – for aquatic chordates

Example: tunicates, fish and amphibians Lungs - for terrestrial chordates

Examples: adult amphibians, reptiles, birds, and mammals

Aquatic Gills

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

The basic function of all of the different types of respiratory organ systems is to bring oxygen rich air from outside the body through the trachea and into the lungs. This allows for oxygen to reach the blood

stream and carbon dioxide to leave the blood stream.

Vertebrate lungs

As you move from amphibians to mammals the surface area of the lungs increase in order to allow a great amount of gas exchange (or a two way flow of air).

Birds, by contrast birds have lungs and air sacs which have only a one-way flow of air This allows for them to have constant contact with fresh air. This adaptation enables them to fly at high altitudes where there is less oxygen.

Section 33-3

Salamander Lizard PigeonPrimate

Nostrils, mouth, and throat

Trachea

Lung

Air sac

Figure 33–10: Vertebrate Lungs

Animal circulation

Circulation systems are the systems used to transport oxygen through the body to the cells so they can perform the essential process of cellular respiration.

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. The heart in any circulatory system is

simply used for pumping the blood. Circulatory systems can either open

systems or closed systems.

Open circulatory systems

Blood is pumped through a system of vessels BUT is only partially contained in these vessels. Most of the time the blood is pumped through open cavities. This system is beneficial to arthropods

and mollusks because the blood comes into direct contact organs and tissues.

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 beneficial to larger

organisms because the blood is kept at a higher pressure which allows for more efficient circulation within the organism.

Section 29-2

Insect:Open Circulatory System

Annelid:Closed Circulatory System

Heartlikestructures

Bloodvessels

Heartlike structure

Small vessels in tissues

Bloodvessels

Hearts

Heart

Sinusesand organs

Figure 29–10 Invertebrate Circulatory Systems

Vertebrate circulatory systems

Chordate circulatory systems range from a single loop system (found in organisms with gills) to double loop systems. Double loop systems of most reptiles

have three chambered hearts Double loop systems of crocodiles, birds

and mammals have four chambered hearts.

Section 33-3

Double-Loop Circulatory SystemSingle-Loop

Circulatory System

FISHESMOST REPTILES

CROCODILIANS, BIRDS,AND MAMMALS

Figure 33–11 The Circulatory Systems of Vertebrates

Animal Excretion

The main waste product created by animals is ammonia. Ammonia is a chemical that is toxic to animals and must

be released through the excretory systems of animals. Most animals have systems that eliminate ammonia

quickly or convert it into a less toxic substance first then removed from body.

Animals excretory systems can be very complex with the main organ being the kidney’s to extremely simple with cells that simply pump the chemicals out.

Aquatic Invertebrate excretion

Some aquatic invertebrates simply diffuse ammonia out their bodies into the surrounding water where it is diluted and carried away. Example: sponges, cnidarians, 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

Section 29-2

Annelid

Arthropod

Flatworm

Malpighian tubules

Digestive tract

Nephridia

Excretory pore

Excretory tubule

Flame cell

Flamecells

Excretorytubules

Nephrostome

Figure 29–11 Invertebrate

Excretory Systems

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.

Response to the environment

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.

Section 29-2

GangliaGanglia

Brain

BrainNerve Cells

Arthropod

Mollusk

CnidarianFlatworm

Figure 29–12 Invertebrate Nervous Systems

Reproduction:Early Development of an Animal Embryo 

During the early development of animal embryos, cells divide to produce a hollow ball of cells called a blastula.

An opening called a blastopore forms in this ball. In protostomes, the blastopore develops into the

mouth. In deuterostomes, the blastopore forms an anus.

 

Animal Body Types

Symmetry With the exception of sponges all animals

exhibit some kind of body symmetry. Radial symmetry: where any number of

imaginary planes can be drawn through the center of the organism giving the body equal halves.

Bilateral symmetry: only have a single imaginary plane that divides the organism into two equal halves.

Section 26-1

Radial SymmetryBilateral Symmetry

Planes ofsymmetry

Plane ofsymmetry

Ventral side

Dorsal side

Posterior end

Anterior end

Figure 26–5 Body Symmetry

Animal Body Types

Cavity Formation: Acoelomates are animals that do not have a

cavity or open coelom between the tissues (ectoderm and endoderm) of the body.

Pseudocoelomates are animals that have a partially lined cavity with mesoderm

A coelomate is an animal that is completely lined with tissue derived from mesoderm.

Note: Refer to the cladogram to distinguish between the different organisms that have these characteristics and how they have evolved.

Section 29-1

RadialSymmetry

Deuterostome Development

Coelom

Pseudocoelom

Protostome Development

RadialSymmetry

Three Germ Layers;Bilateral Symmetry

Tissues

Multicellularity

Chordates Echinoderms Arthropods

Annelids Mollusks

Roundworms

Flatworms

Cnidarians

Sponges

Single-celled ancestor

Invertebrate Cladogram

Section 33-1

Nonvertebrate chordates

Jawless fishes

Cartilaginous fishes

Bony fishes

Amphibians

Reptiles

Birds

Mammals

Figure 33–2 A Cladogram of

Chordates

Section 33-1Figure 33–4 Diversity of Chordates

Directional Anatomy Terms