Download Animal Taxonomy

Animal Taxonomy
Phylum Porifera
Sponges lack true tissues and organs
Have 2 layers of cells
Filter feeders using choanocytes, flagellated collar cells which create a
water current
Most sponges are hermaphrodites
Cnidarians
 Jellyfish (medusa), corals, hydras, anemones (polyps)
Radially symmetrical, have a gastrovascular cavity and a nerve net
Have 2 layers of cells
Carnivores that use tentacles armed with cnidocytes to capture prey
Platyhelminthes
Flatworms have a gastrovascular cavity and are acoelomates
Planarians have light-sensitive eyespots and centralized nerve nets, found
in all types of moist habitats
Tapeworms and flukes are parasites that have a complex life cycle involving
2 or more hosts
Annelids, Molluscs and Arthropods are protostomes
Have spiral, determinate cleavage
Mesoderm splits to form the coelom
Mouth forms from the blasotpore
Molluscs are soft-bodied animals, but most are protected by a hard shell
Phylum Mollusca includes snails, slugs, oysters, octopuses and squids
All molluscs have a similar body plan with three main parts: muscular foot,
mantle and visceral mass
Have a complete digestive tract
Open circulatory system
Have a siphon system to bring water in and out of their bodies and gills for
gas exchange
Nephridium help excrete nitrogenous wastes
Cephalopods have large brains, eyes and are highly intelligent
Polyplacophora (chitons) oval-shaped marine animals encased in an armor of
eight dorsal plates
Gastropoda (snails and slugs) Most have a single, spiraled shell, and exhibit
torsion, which causes the animal’s anus and mantle to end up above its head
Bivalvia (clams, oysters) have 2 shells
Cephalopoda
(squids, octopuses, cuttlefish, and chambered nautiluses)
beak-like jaws surrounded by tentacles of their modified foot
Annelids are segmented worms
earthworms, polychaetes, leeches
Annelids have bodies composed of a series of fused rings each with circular
and longitudinal muscles which contract against fluid in the coelom so they
can move (hydrostatic skeleton)
Annelid characteristics
Gas exchange is through their skin
Closed circulatory system with multiple hearts
Metanephridia excrete nitrogenous wastes through the skin
Have cerebral ganglia and a dorsal nerve cord
Have a true coelom
Have a complete digestive system with many parts
Nematodes are nonsegmented pseudocoelomates
Nematodes, or roundworms, are found in most aquatic habitats, in the soil,
in moist tissues of plants, and in body fluids and tissues of animals
The cylindrical bodies of nematodes are covered by a tough coat called a
cuticle
Arthropods
Have regional segmentation
Different segments are specialized for different functions
Jointed appendages
Each is modified for: walking, feeding, sensory reception, copulation, or
defense
Cephalization
Many sensory structures are found at the anterior end
Organ systems
Complete digestive system
Open circulatory system with hemolymph
Excretory organs are Malpighian tubules, empty nitrogenous waste into
digestive tract
Gas exchange through trachea with spiracles that open to the outside
Pair of ventral nerve cords with several segmental ganglia; anterior ganglia
are fused into a dorsal brain
Gas exchange structures
Feathery gills in aquatic species
Tracheal systems in insects
Book
lungs in spiders
Exoskeleton of protein and chitin
Thin and flexible at joints, thick and hard at others
Provides protection, points of muscle attachment, waterproofing
Has to be shed for animal to grow
Open circulatory system
Hemolymph leaves the heart and passes into sinuses which surround tissues
and organs and reenters the heart through pores with valves
Classes
Chelicerates spiders, scorpions, ticks, mites; named for their feeding
appendages, the chelicerae
Hexapoda, insects, has more species than all other forms of life combined;
have several complex organ systems; many undergo metamorphosis during
their lives
Crustaceans, subphylum Crustacea, typically have branched appendages
that are extensively specialized for feeding and locomotion
Decapods are all relatively large crustaceans and include lobsters, crabs,
crayfish, and shrimp
Echinoderms and chordates are deuterostomes
Radial, determinate cleavage
Development of the coelom from folding of the archenteron
Formation of the anus from the blastopore
Echinoderms
A thin, bumpy or spiny skin covers an endoskeleton of hard plates
Have a water vascular system, a network of hydraulic canals branching into
tube feet that function in locomotion, feeding, and gas exchange
Chordates and subphylum vertebrata
Characters of Chordates
Chordataes are bilaterial deuterostomes
Four key characters of chordates:
Notochord
Dorsal, hollow nerve cord
Pharyngeal slits or clefts
Muscular, post-anal tail
Some species have some of these traits only during embryonic development
Notochord
The notochord is a longitudinal, flexible rod between the digestive tube
and nerve cord
It
provides skeletal support throughout most of the length of a chordate;
most vertebrates develop a jointed skeleton
Dorsal, Hollow Nerve Cord
The nerve cord of a chordate embryo develops from a plate of ectoderm
that rolls into a tube dorsal to the notochord
The nerve cord develops into the central nervous system: the brain and the
spinal cord
Pharyngeal Slits or Clefts
In most chordates, grooves in the pharynx called pharyngeal clefts develop
into slits that open to the outside of the body
Functions of pharyngeal slits:
Suspension-feeding structures in many invertebrate chordates
Gas exchange in aquatic vertebrates
Develop into parts of the ear, head, and neck in terrestrial vertebrates
Muscular, Post-Anal Tail
Chordates have a tail posterior to the anus
In many species, the tail is lost during embryonic development; if not it can
often be used for movement
Urochordates and cephalochordates
Although invertebrates, are more closely related to vertebrates
Tunicates and lancelets: marine filter feeders
Jawless fish
Hagfishes are jawless marine craniates that have a skull and axial rod of
cartilage along their back
Secrete massive quantities of slime from glands in their skin
Scavengers
Derived Characters of Vertebrates
Vertebrates have the following derived characters:
Vertebrae enclosing a spinal cord
An elaborate skull
Fin rays, in aquatic forms
Cephalaspidomorphi
Lampreys
They are jawless aquatic vertebrate with have cartilaginous segments
around the notochord and part of the nerve cord
Parasites of fish
Chondrichthys
Sharks, Rays, skates
Members
of class Chondrichthyes have a skeleton composed primarily of
cartilage
Osteichthies
Have a bony endoskeleton
Fishes control their buoyancy with an air sac known as a swim bladder
Fishes breathe by drawing water over gills in chambers covered by a bony
flap called the operculum
Have countercurrent flow of water and blood in their gills
Have a 2 chambered heart
Marine fish excrete salt from their gills and make a small amount of urine
Freshwater fish excrete large amounts of dilute urine to maintain
osmoregulation
Lateral line allows them to feel vibrations in the water
Derived Characters of Tetrapods
Tetrapods have some specific adaptations:
Four limbs and feet with digits
Ears for detecting airborne sounds
Amphibians: Frogs, salamanders, caecilians
Most amphibians have moist skin that complements the lungs in gas
exchange
Amphibian means “two lives,” referring to the metamorphosis of an aquatic
larva into a terrestrial adult; need water for reproduction
Have a 3 chambered heart
Derived Characters of Amniotes
Amniotes produce the amniotic egg, which contains membranes that
protect the embryo
The extraembryonic membranes have various functions
Have relatively impermeable skin and can use the muscles of the rib cage
to ventilate the lungs
Reptiles
Tuataras, lizards, snakes, turtles, crocodilians, birds, and the extinct
dinosaurs
Reptiles have scales
They lay shelled eggs on land
Most are ectothermic
Have a 3 chambered heart
Birds
Birds
are brachiosaurs, but almost every feature of their reptilian anatomy
has been modified for adaptation to flight
A bird’s most obvious adaptations for flight are its wings and feathers
Bones are light-weight and hollow
Have a 4 chambered heart and one way flow of oxygen through their lungs
Sea birds excrete salt through salt glands in their nostrils
Mammals are amniotes that have hair and produce milk
Mammary glands, which produce milk, are a distinctively mammalian
character
Hair is another mammalian characteristic
Mammals generally have a larger brain than other vertebrates of
equivalent size
Have a 4 chambered heart
Monotremes
Monotremes are a small group of egg-laying mammals consisting of echidnas
and the platypus
Marsupials
Marsupials include opossums, kangaroos, and koalas
A marsupial is born very early in its development
It completes its embryonic development while nursing in a maternal pouch
called a marsupium
Eutherians (Placental Mammals)
Compared with marsupials, eutherians have a longer period of pregnancy
Young eutherians complete their embryonic development within a uterus,
joined to the mother by the placenta
Derived Characters of Primates
Most primates have hands and feet adapted for grasping
Other derived characters of primates:
A large brain and short jaws
Forward-looking eyes close together on the face, providing depth
perception
Well-developed parental care and complex social behavior
A fully opposable thumb
Living Primates
There are three main groups of living primates:
Lemurs, lorises, and pottos
Tarsiers
Anthropoids (monkeys and apes)