Survey of Phyla
- Deuterostomes
* Blastopore becomes anus
* indeterminate development
* enterocoelous, usually
* radial cleavage - Protostomes
* Blastopore becomes the mouth
* determinate development
* schizocoelous, usually
* spiral cleavage - The protists choanoflagellates are the closest living groups to animals
- Porifera: Sponges
* Cellular level of organization
* Asymmetrical
* Consists of different cells types that have unique functions
* ==Walls have spicules for strength==
* Reproduce sexually (hermaphroditic) or asexually (fragmenting, budding, or producing gemmules)
* Sessile, with free living larvae
* Water is drawn into and circulated through the hollow body of the sponge by the movement of the choanocytes’ flagella, bringing in food and oxygen and carrying out wastes (filter feed)
* Amoebocytes are multi-purpose cells
* Gemmules: Packets of cells covered in a protective coating making them resistant to desiccation.
* Sponge sperm are transformed choanocytes. - Cnidaria: Jellyfish, anemones
* Tissue level of organization
* Radial symmetry
* Diploblastic
* Two body forms: polyp and medusa
* ==Cnidocytes: nematocysts==
* Neural net
* Have sensory receptors (touch, gravity, light)
* Sexual and asexual reproduction
* Corals build calcium carbonate exoskeletons (coral reefs)
* Can spend most of their life in one form or alternate between them
* Some polyps are colonial
* Body has one opening: 2-way gut
* The body wall has two layers: the epidermis and the gastrodermis.
* Between these layers is the mesoglea, which may be acellular or cellular.
* The first creatures to have extracellular digestion.
* The cells lining the gastrovascular cavity secrete digestive enzymes that partially digest food items and other cells phagocytize the fragments
* In species with both life forms, gamates are produced by the medusa and develop into a planula that becomes a polyp
* In species with only the polyp form asexual reproduction can occur along with the production of gametes and develop into a planula that becomes a polyp
* In species with only the medusa form the planula only develops into another medusa - Platyhelminthes: Flatworms, tapeworms, flukes
* Organ level organization
* Bilateral symmetry
* Cephalized but most lack mouths
* Triploblastic
* Acoelonmate (solid body)
* Flat
* Sexual reproduction
* Free living and parasitic
* Can live in marine, freshwater, and moist terrestrial environments
* Excretory system (flame cells)
* Ganglion and nerve cords
* Eye spots
* Flatworms
* Can be carnivores or scavengers
* Digestion is primarily done by phagocytosis in the gut but some extracellular digestion occurs
* Two way gut
* First creatures to have an execratory system that deals with nitrogenous waste and maintains water balance
* Free living flat worms are the first creatures to have internal fertilization
* Able to regenerate lost parts
* Parasitic flatworms can be free ling or parasitic
* Tape worms
* Ones that live in the gut of vertebrates lack a mouth and digestive system
* Mostly composed of reproductive proglottids
* Contain both male and female sex organs
* When mature they break off and are excreted in the faeces - Rotifera: Rotifers
* Organ level of organization
* Bilateral symmetry
* Triploblastic
* 1- way gut
* Pseudocoelomate
* Microscopic
* Pseudocoelom acts as a hydro static skeleton
* ==Corona cilia is used for locomotion and feeding==
* Most are freshwater
* Can become dormant when dehydrated
* Transparent outer cytoskeleton
* Telescopic foot with a toe containing a cement glad that allows it to attach to objects
* Filter feed on algae, organic particles, dead bacteria, and protozoa
* Some reproduce sexually through internal fertilization
* Some reproduce by parthenogenesis
* Bdelloidea lack males and females produce diploid eggs
* In some groups when there are unfavourable conditions unfertilized eggs will become males and fertilized ones will wait until favorable conditions arise - Mollusca: Snails, clams, oysters, octopus
* Organ level of organization
* Most bilaterally symmetrical but some are secondarily asymmetrical
* Triploblastic
* 1-way gut
* Eucoelomate
* Open circulatory system that has a heart
* Most are marine
* ==Most have a scraping tongue (radula)==
* Nephridia for removal of nitrogenous wastes
* Body is covered on the dorsal side with a thickened mantle
* Shells are secreted by the outside surface of the mantle and are made of calcium carbonate.
* Not all molluscs have shells
* Molluscs other than cephalopods have a muscular foot, which is used mostly for locomotion, but may also be used for digging or attachment to a surface
* Sexual reproduction with most being dioecies but some being hermaphroditic.
* Most fertilization is internal, but marine bivalves have external fertilization - Annelida: Segmented worms
* Organ level of organization
* Bilateral symmetry
* Triploblastic
* 1-way gut
* Metameric segmentation:
different segments able to be differentiated for different functions
* Each segment has an excretory organ
* Closed circulatory system
* Ventral nerve cord
* Longitudinal circular muscles
* Hydrostatic skeleton
* Exterior and interior segmentation may not line up
* Sexual reproduction some are hermaphroditic
* Marine worms are mostly dioecious and have external fertilization
* Earthworms and leeches are hermaphroditic
- Nematoda: roundworms
* Organ level of organization
* bilateral symmetry
* Triploblastic
* 1-way gut
* Pseudocoelomate
* Found in all environments
* Covered by a flexible cuticle that is eventually moulted
* Sexually dimorphic
* Internal fertilization
* Can be parasitic
* Only longitudinal muscles, produces thrashing motion
* Can infect humans
* Hookworms, pinworms, filariasis (elephantiasis) - Tardigrada
* Organ level of organization
* Bilateral symmetry
* Triploblastic
* Eucoelomate around gonad, hemocoel everywhere else
* 1-way gut
* Lack circulatory and respiratory system
* Brain and simple nervous system
* Segmented body
* Sexual and parthenogenesis reproduction
* Found in freshwater and marine environmetns including arctic and antarctic stream, high altitudes, hot springs, prefer moist terrestrial habitats
* Can enter a dormant state called a tun which allows them to survive extreme conditions including temperatures -328 and 300℃, radiation, the vacuum of space, anoxic conditions, and dessiccation for up to 10 years - Arthropoda:
* Organ level of organization
* Bilateral symmetry
* Triploblastic
* 1-way gut
* Eucoelomate
* Segmented bodies
* ==Rigid chitonous exoskeleton that is moulted==
* ==Jointed appendages==
* 65% of all species
* Segments specialized into functional groups (tagmata)
* Compound eyes
* Terrestrial insects have a tracheal tube system for respiration
* Sexual reproduction with internal fertilization
* Sensory setae on their body
* Flies and butterflies have taste buds on their feet
* Open circulatory system
* Nervous system is composed of a double chain of ventral ganglia with three fused pairs of dorsal ganglia that make up the brain.
* Aquatic arthropods have gills
* Arachnids have book lungs instead of or in conjunction with a tracheal system - Echinodermata: Echinoderms
* Organ level of organization
* Penta-radial symmetry
* Triploblastic
* 1-way gut
* Eucoelomate
* ==Water-vascular system: enters through the madreporite and the radial canal goes down the appendages from the ring canal in the center==
* ==Tube feet for locomotion, gas exchange and feeding==
* Endoskeleton made of calcium carbonate plates (ossicles)
* Mouth on the oral (bottom) anus on the aboral (top) surface
* Nervous system
* Most is sexual reproduction with external fertilization
* Species with asexual reproduction can regenerate limbs
* Free living bilateral larvae
* Marine dwelling - Chorodata: chrodates
* Organ level of organization
* Nervous system
* Closed circulatory system
* Amniotic eggs (some but not all)
* Bilaterally symmetrical
* Eucoelomate
* 1-way gut
* Endoskeleton
* ==Notochord==
* ==Pharyngeal gill slits==
* ==Dorsal hollow nerve cord==
* ==Postanal tail==
* Most traits are only seen in larval stages
* Subphyla:
* Urochordata – tunicates
* Cephalochordata – lancelets (only ones to have chordate features as adults)
* Vertebrata - vertebrates
* Vertebral column: all but hagfish and lamprey
* Head with special sense organs
* Neutral crest: cells that contribute to the development of many structures
* Internal organs
* Endoskeleton made of bone or cartilage