Subkingdom Parazoa
Phylum Porifera
Habitat
5000 species (All aquatic, some brackish, most marine)
Anatomy
Sessile
Two layers imbedded in a gelatinous matrix (mesohyl)
Outer layer of epidermal cells
Inner layer of choanocytes or epidermal cells
Amoebocytes and spicules in mesohyl
Skeleton
Spicules of Calcium carbonate or silicon
Spongin is a flexible skeleton
Cells
Porocytes -- Form incurrent pores in the epithelial body wall
Choanocytes
Flagellated cell
Contain collars
Create water current and trap food
Amoebocytes
Wandering cells in the mesohyl
Can differentiate into any other cell type
Functions
Food digestion
Nutrient distribution
Food storage
Gamete formation
Spicule formation
Epidermal cells
Line the outside and sometimes the spongocoel and canals
Basic body plan
Choanocytes on inside create a water current
Water enters incurrent pores
Pores are formed by porocytes
Goes into the spongocoel
Central cavity of the sponge
Exits the sponge through oscula
Large excurrent opening of the spongocoel
Filter feeders
All cells capable of phagocytosis / intracellular digestion and absorption.
Feeding
Choanocytes
Collar sieve with mucous
Creates water current and traps food
Slides down and phagocytized at base
Amoebocytes
Collects, digests, distributes, and stores food
Other physiology
No respiratory or excretory organs
Gas exchange and ammonia removed by water flow
Reproduction
Asexual
Regeneration powers
Budding (rare)
Gemmules
Gemmules remain dormant during droughts and freezes
Released during good conditions
Sexual
General
Monoecious more common than dieocious
Viviparous more common that oviparous
Gametes
Amoebocytes and choanocytes can differentiate into egg and sperm
Egg remains in mesohyl
Eggs may engulf nurse cells to accumulate nutrients
Sperm is released
Fertilization
Sperm is phagocytized by choanocytes of another sponge
Choanocyte delivers sperm to egg
Choanocytes releases sperm nuclei or both are engulfed
Larvae
Zygote develops into a flagellated larvae which escapes through the osculum
Most have parenchymella larvae
Cilia all over
Some have amphiblastula
cilia over one end
Metamorphosis
Inversion similar in gastrulation
Flagella now located on the inside
Subkingdom Eumetazoa
Branch Radiata
Characteristics
Radial symmetry
Diploblastic
Phylum Cnidaria
Gastrovascular cavity with 1 opening
Polyp (sessile-attached by aboral end) and medusa (floating - mouth/anus facding down) body forms
Tentacles with cnidocytes with nematocysts (stingers) to capture prey and for defense
Carnivorous
Class Scyphozoa --jellyfish; class Anthozoa -- sea anemones and corals (secrete shell); class Hydrozoa
Branch Bilateria
Acoelomates
Characteristics
Triploblastic (ectoderm, endoderm, and mesoderm)
Bilateral symmetry
Acoelomates
No fluid-filled body cavity
Phylum Platyhelminthes (Flatworms)
Poss several organs
Class Turbellaria
Free living
Carnivorous
Rudimentary brain
Class Trematoda (flukes)
All parasites with two or more hosts in their life cycle
Class Cestoda (tapworms)
All parasites of vertebrate’s digestive system
No digestive system
Pseudocoelomates
Fluid-filled body cavity not completely lined with mesoderm
Phylum Nematoda (roundworms)
Dioecious (separate sexes)
Important plant and animals pathogens
Coelomates
Characteristics
Contain a true coelom (body cavity completely lined with mesoderm)
Coelom used as a hydrostatic skeleton, for storage, and to cushoin organs
Protostomes
Characteristics
First evagination (blastopore) of gastrula forms mouth
Coelom forms by splitting of mesoderm
Spiral and determinant cleavage
Phylum Mollusca
Characteristics
Mostly marine
3 distinct body parts
Visceral mass - soft (contains organs)
Foot - muscular (movement)
Mantle - covers visceral mass (secretes shell)
Many show cephalization
Class Gastropoda
Slugs and snails
Herbivorous
Torsion
One side of visceral mass grows faster than other
Results in anus being above mouth
Use radula for feeding / rasping
Class Bivalvia
Clams (moves with foot), oysters, mussels, and scallops (moves by flapping shell)
2 shells hinged at the back, kept colesed by adductor muscle
Filter feeders
Class Cephalopoda
Octopuses and squid
Carnivorous (highly cephalized -- need to be to locate and capture prey)
Squid - reduced internal shell, open sea, jet propulsion
Octopus - no shell, ground dwelling, moves with tentacles
Phylum Annelidia
Characteristics
Segmented worms
Segments partitioned by septa - blood vessel, dorsal nerve and digestive tract transcend segments
Complete digestive tract
Cutaneous respiration
Hermaphroditic
Class oligochaeta
Earthworms
Important in tilling earth (1 acres may contain 50K worms, tilling 18 tons per year)
Class Polychaeta
Contain one pair of parapodia per segment
Parapodia function in locomotion and gas exchange
Probable gave rise to arthropods (parapodia became specialized appendages)
Class Hirudinea
Leeches (exoparasites)
Phylum Arthropoda
Characteristics
Most successful animal phylum
Species diversity (1 million species / 3/4 all animal species)
Distribution (almost everywhere)
Number of individuals (1 billion billion)
Probably evolved from the annelids
Number of segments became reduced
Segments became specialized (walking, feeding, sensory, copulation and defense)
Contain a hard exoskeleton (protein and chitin)
Protection
Muscle attachment
Water conservation - -important for movement onto land
Support -- important for movement onto land
Must molt (exoskeleton does not grow)
Extensive cephalization (eyes, olfactory receptors, antennae - for touch & smell)
Open circulatory system with hemolymph
Compete with humans for food and spread diseases
Essential for pollination of many flowers and produce many unique and useful products (honey and silk)
Efficient breathing apparatus (gills, trachea, book lungs)
Metamorphosis is common (reduces competition between juveniles and adults)
Subphylum Chelicerata
Characteristics
6 pairs of appendages including chelicerae (fang-like appendages used in feeding) and pedipalps
No attennae or mandibles
Mostly terrestrial
Class Arachnida
Scorpions, spiders, mites, and ticks
6 pairs of appendages
Chelicerae, pedipalps (sensing and feeding), 4 pairs of legs
Feedign (all predacious)
Fang-like chelicerae
Poison glands
Secrete digestive juices
Suck up liquid soup
Book lungs (unique to this class) and trachea system
Malpighian tubules for secretion (empties urine into digestive tract - nearly dry urine/feces mix)
Eight simple eyes
Silk
Protein made by abdominal glands
Spinnerets spin silk into fibers
Innate ability to produce webs, drop lines, wrap eggs, make gifts (courting rituals)
Scorpions
Feed on insects and spiders, can sense vibrations, has stinger on tails)
Ticks and Mites
Spread diseases like Rocky Mountain spotted fever and Lyme disease / chiggers
Subphylum Uniramia
Characteristics
Claw-like chelicerae replaced with jaw-like mandibles
Pedipalps replaced with maxillae for food handling
Have 1 pair of antennae
Class Diplopoda -- Millipedes
2 pairs of legs per segment
Herbivores
Earliest land animals (ate mosses)
Class Chilopoda -- Centipedes
1 pair of legs per segment
Carnivores (earthworms, cockroaches, and insects)
Insecta
Entomology - scientific study of insects
Most successful of all arthropod groups
Flight
1 or 2 pairs of wings (from cuticle, not appendages like bats and birds)
Escape, finding mates and food, dispersal
3 pairs of walking legs
Gas exchange by trachea (branching tubes) and spiracles (opening)
Metamorphosis
Complete (drastic change)
(egg larvae pupil adult)caterpillar - cocoon - butterfly)
Incomplete
(egg immature nymphs adult)
Can be vectors for disease (malaria, African sleeping sickness, etc)
Subphylum Crustacea
Lobsters, crayfish (fresh water), crabs, shrimp, krill, barnacles
Sow bugs and pill bugs (rolly pollies) are terrestrial
Separate sexes
2 pairs of antennae
Deuterostomes
Characteristics
Radial indeterminate cleavage
Blastopore forms anus
Coelom forms from endoderm outpocketing
Phylum Echinodermata
Characteristics
No cephalization or segmentation
Calcareous endoskeleton covered with skin (skin protected with pincer like pedicellariae)
Separate sexes
Sessile or sedentary
Adults have radial symmetry
Juveniles metamorphosize from bilateral symmetry to radial symmetric adults
Water vascular system (locomotion, feeding and gas exchange) from coelom
Fluid moved by cilia
Used for gas exchange, waste removal, movement and feeding
All marine
Strong powers of regeneration
Class Asteroides -- sea stars (feed on mollusks)
Class Ophiuroidea -- brittle stars (flexible arms); scavengers
Class Crinoidea -- sea lilies (often attached filter feeders)
Class Holothuroidea --sea cucumbers (lost shell) -- deposit feeders in mucky areas
Class Echniodea -- sea urchins and sand dollars (feed on seaweed)
Phylum Chordata
Characteristics
Notochord (in all chordate embryos)
Longitudinal, flexible rod
Between gut and nerve chord
Serves as skeleton in some vertebrates
Reduced to pads between vertebrates in humans
Hollow-dorsal nerve chord
Ectoderm rolls in a tube dorsal to notochord
Other phyla have solid nerve chord, usually ventral
Forms central nervous system (brain and spinal cord)
Pharyngeal slits (in all chordate embryos)
Slits in pharynx
Filter feeding
Gas exchange
Muscular post-anal tail
Subphylum Cephalochordata
Subphylum Urochordata
Subphylum Vertebrata
Characteristics
Sexually mature larvae
Highly cephalized
Nerve chord protected with vertebrate
2 pairs of appendages (fins, wings, legs, etc.)
Living endoskeleton (contains osteocytes - skeleton can grow)
Closed circulatory system (blood stays in vessels)
Waste removed with kidneys
Dioecious - separate sexes (sexual reproduction)
Class Agnatha (jawless fish)
Uses mouth to latch onto fish, rasps hole in fish, and feeds on blood
Class Chondrichthyes (cartilaginous fish) - sharks and rays
Carnivorous (exceptions: whale shark - filter feeder)
Good senses (electrical impulses, water pressure, etc.)
Oviparous (young hatch from eggs outside body); ovoviviparous (young hatch from eggs in the mother’s uterus); or viviparous (young are nourished by placenta)
Class Osteichthyes (bony fish)
Swim bladder (fills with gas - from blood) to let fish float
Operculum (covers gills - brings water in mouth and out gills)
Oviparous
Most numerous of all vertebrates
Class Amphibia
Three orders
Salamanders(aquatic, land, or both)
Caecilians(worm-like -- tropics)
Toads and frogs(metamorphosis)
Iinefficient lungs; cutaneous respiration
Metamorphosis:young do not compete with adults for resources
Tadpoleherbivores (aquatic)
Adultsinsects (land or aquatic)
External fertilization
Class Reptilia
Keratin - water proof skin
obtain oxygen from lungs
Oviparousinternal fertilization
shell on amniote egg
Ectothermic“cold-blooded”
energy conservation (10% the food requirement of mammals)
Evolution (one branch contained the turtles, snakes and lizards)
(other branch contained the dinosaurs, crocodiles, and alligators - this branch gave rise to the mammals and latter the birds)
ascended from amphibians
gave rise to birds and mammals
3 extant orders:
lizards and snakes
turtles
alligators and crocodiles
Dinosaurs as quick moving endotherms (went extinct around time gymnosperms gave rise to angiosperms - mammals radiated when dinosaurs became extinct)
Class Aves
Evolved from reptiles
retained amniote egg and scales
Hollow bones, toothless, absence of some organs (example - only one ovary)
Endothermic
Oviparous
internal fertilization (though most birds have no penis)
eggs kept warm
Feathers from keratin (hair, fingernails, scales)
Ratite birds (flightless - lacking breast muscle - ostriches)
Carinate birds (flight birds - includes penguins)
Class Mammalia
-from reptiles (before birds)
Hair (insulation)
4 chambered heart (keeps oxygenated and deoxygenated blood separate)
Differentiation of teeth
Large brain - capable of learning
Diaphragm (efficient breathing)
Endothermic (warm blooded)
Mammary glands (nourish young)
Viviparous
Internal fertilization
3 Subclasses:
1. Monotremes (egg-laying mammals)
platypuses and spiny anteaters
reptilian type egg
hair and mammary glands (no nipples)
2. Marsupials (mammals with pouches)
kangaroos and koalas
reptilian type egg
hair and mammary glands
young craw out of reproductive tract very early in development, craw into pouch and attaches to nipple for nourishment, and develops in pouch)
3. Placental mammals