Animal Diversity
Animal Diversity
Overview
Animal Organization & Classification
Sponges
Jellyfish
Flatworms
Segmented worms
Arthropods
Chordates
Fish
Amphibians
Reptiles
Birds
Mammals
Animal Diversity
Animal Organization & Classification
●
●
All living things are organized
Animals have cells as their smallest
functional level of organization
–
Unicellular animals
●
●
–
Exhibit the simplest levels of
organization
Exist as a single cell
Multicellular animals
●
Exhibit more complex levels of
organization
–
–
–
Tissues
Organs
Organ systems
Animal Diversity
Animal Organization & Classification
●
Tissues
–
●
Like cells organized together with a
common function
Tissue Types
–
Epithelial tissue
●
–
Muscle tissue
●
–
Contract
Nervous tissue
●
–
Protect
Excitable
Connective tissue
●
Bind other tissues together
Animal Diversity
Animal Organization &
Classification
●
Organs
–
●
Two or more tissues
organized together with a
common function
Organ Examples
–
Skin
–
Heart
–
Eye
Animal Diversity
Animal Organization &
Classification
●
Organ Systems
–
●
●
Two or moreorgans organized
together with a common function
Organ System Examples
–
Nervous system
–
Cardiovascular system
–
Reproductive system
All the organ systems
constitute the entire organism
Animal Diversity
Animal Organization & Classification
●
Animals develop layers of cells during the development of the fertilized egg
–
These cell layers are known as germ layers and are the source of the tissue of most animals
–
Diploblastic animals develop two germ layers
–
Triploblastic animals develop three germ layers
●
Another group of animals, the parazoa (sponges), are not organized into true tissues and
so lack organs
Animal Diversity
Animal Organization & Classification
●
●
As a result of the development of germ layers various body shapes and
symmetry develop in the adult form of an animal
These body shapes and their symmetry can be described in three ways;
–
Asymmetry
●
–
Radial symmetry
●
–
Can’t be divided into mirror images
Can be divided through their central axis in many ways to create mirror images
Bilateral symmetry
●
Can only be divided one way through their central axis to form mirror images
Animal Diversity
Sponges
Leucosolenia-one of the
smallest sponges
–
Collection of
independent cells
which are loosely
organized
–
No tissues are formed
–
Primarily marine
–
Range from ~1mm to
as large as a barrel
Caribbean barrel sponge,
Xestospongia muta
Animal Diversity
Sponges
●
Body Forms
–
All sponges are
asymmetrical
●
Ascon
–
–
●
Sycon
–
●
Vase-like
Simplest and least common
Folded body walls
Leucon
–
Extensively branched canal
system
Animal Diversity
Sponges
●
Body Functions
–
Filter Feeding
●
●
–
Diffusion
●
–
Oxygen in, waste materials out
Communication
●
●
–
Single sponge can filter 20 liters/day
Phagocytosis of filtered foods
Lack nervous system
Chemical signaling between cells is suspected
Reproduction
●
●
●
Monecious (contain both male & female
reproductive structures in a single organism)
No self-fertilization
Fertilization is external (in the water outside
the sponge’s body)
Animal Diversity
Jellyfish
–
Diploblastic
–
Radial or bilateral symmetry
●
●
Radial symmetry seen mostly in sessile (nonmotile) species
Bilateral symmetry seen mostly in motile
species
–
Neural or nerve net: a diffuse form of a
nervous system
–
Cnidocysts: specialized cells used for
feeding, defense, and attachment
–
Mostly marine but some freshwater
species exist
–
Body forms
●
●
Medusa-swimming form
Polyp-stationary form
Animal Diversity
Flatworms
–
Triploblastic
–
Bilateral symmetry
–
Flat body form with no internal
cavities
–
Partial cephalization and
simple nervous system
–
Specialized structures for sight,
smell, and balance
–
Produce a mucous layer and
use cilia on the bottom of their
bodies to glide on the mucous
Animal Diversity
Flatworms
–
Reproduction
●
●
Asexually by binary
fission
Sexually by penis
fencing
Animal Diversity
Segmented Worms
–
Triploblastic body forms
●
Metamerism (segments)
–
Bilateral symmetry
–
Locomotion
●
●
Hydrostatic skeleton
Paired setae
–
Closed circulatory system
–
More complex nervous system over
flatworms
–
Reproduction
●
●
–
Monecious
Cross-fertilization is the normal
Includes the earthworms, leeches, and
marine worms
Animal Diversity
Arthropods
–
Exoskeleton
–
Segmented body
–
Paired, jointed legs
–
Ventral nervous system
–
Complete digestive tract
–
Specialized respiratory and
sensory organs
–
Ability to exhibit
metamorphysis (shapeshifters) during development
Animal Diversity
Arthropods
●
Metamorphosis
–
Arthropods can exhibit
changes in their body shapes
during various stages of
development
–
Results in reduced competition
between immature forms and
adult forms of the animal
●
●
●
Eat different foods
Occupy different habitats
Example; Caterpillar v. Butterfly
Animal Diversity
Chordates
●
Bilaterally symmetrical
All possess a
●
Notochord
–
Develops into a vertebral
column
●
Dorsal hollow nerve cord
●
Pharyngeal slits
●
Post-anal tail
Animal Diversity
Chordates
●
Include
–
Fish
–
Amphibians
–
Reptiles
–
Birds
–
Mammals
Animal Diversity
Chordates
●
Fish
–
Bilaterally symmetrical
–
Gills
–
Complete digestive & circulatory
systems
–
Bony or cartilaginous skeletons
–
Many specialized sensory organs
–
Diecious
●
–
Separate males & females
Include hagfish, lamprey, sharks,
rays, skate, & body fish
Animal Diversity
Chordates
●
Amphibians
–
Bilaterally symmetrical
–
Ectothemic (“cold-blooded”)
–
Diecious with elaborate courting routines
–
Most divide time between land and water
–
3-chambered heart
–
Respiration through lungs, skin, and
mouth
–
Well developed eyes, ears, and
cutaneous sensory organs
–
Include caecilians, salamanders, newts,
frogs and toads
Animal Diversity
Chordates
●
Reptiles
–
Bilaterally symmetrical
–
Terrestrial
–
Diecious but some species females can
produce offspring without a male
–
Dry skin with epidermal scales
–
Respiration by lungs
–
3 chambered heart with perforated partion
of the ventricle
–
Metanephric kidney
–
Internal fertilization
–
Amniotic eggs
–
Includes turtles, crocodiles, alligators,
snakes, and lizards
Animal Diversity
Chordates
●
Birds
–
Bilaterally symmetrical
–
Terrestrial
–
Diecious
●
Males lack a penis except for the
waterfowl and ostrichs
–
Feathers
–
Light, flexible skeleton designed for
flight
–
Horny bill lacking teeth
–
High metabolic rate
–
Endothermic (“warm-blooded”)
Animal Diversity
Chordates
●
Mammals
–
Mammary glands
–
Hair
–
Diaphragm
–
3 middle ear bones
–
Heterdont dentition
●
Specialized teeth for different foods
–
Sweat, sebaceous, & scent glands
–
4-chambered heart
–
Large cerebral cortex