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Levels of organisational complexity

protoplasmic, cellular, cell-tissue, tissue-organ and organ-system

Symmetry

Asymmetry, spherical, radial and Bilateral

Radial Cleavage

A type of embryonic development in deuterostomes in that the planes of cell division that transform the zygote into a ball of cells are either parallel or perpendicular to the polar axis, thereby aligning tiers of cells one above the other.

Spiral cleavage

A type of embryonic development in protostomes, in which the planes of cell division that transform the zygote into a ball of cells occur obliquely to the polar axis, resulting in cells of each tier sitting in the grooves between cells of adjacent tiers.

Protoplasmic

all function within one cell

Cellular level

aggregation of undifferentiated cells

Cell-Tissue

aggregations of similar cells into patterns or layers, specialized for a common function

Tissue-organ

tissues combined with other types of tissue to form a structure with a more complex function than a single tissue

Organ-system

group of organs that work together to perform a specific function

monophyletic

Pertaining to a group of taxa that consists of a common ancestor and all of its descendants. A monophyletic taxon is equivalent to a clade.

Blastopore

Gut opening

Incomplete gut

one opening

coloem

fluid filled cavity around gut

radial symmetry

divided into two similar halves by more than 2 planes passing through longitudinal axis--\> sessile animals

bilateral symmetry

Divided along a saggital plane- two mirrored portions (right and left)--\> for directional movement.

Cephalisation

concentration of nerve tissues and sense organs at anterior creating 'head end'.

Acoleomate

body without coloem. Blastocoel filled with mesoderm.

Pseudocoleomate

Mesoderm lines outer edge of blastocoel next to ectoderm.

Coloemate

blastocoel filled with mesoderm and new cavity formed inside.

Protostome

Spiral cleavage, Blastopore becomes mouth, Schizocoleous coloem formation.

Deuterostome

Radial cleavage, Blastopore becomes anus, Enterocoelous coloem formation.

Schizocoleous coloem formation

Blastopore cells migrate into blastocoel and mesoderm bands split to form coloem.

Enterocoelous coloem

Coloem forms from pockets of archenteron (primitive gut) that push out into blastocoel.

paraphyletic group

composed of some but not all members descending from a common ancestor

Devices for locomotion in unicellular eukaryotes

pseudopodia, cillia or flagella

Pseudopodia

A cellular extension of amoeboid cells used in moving and feeding. Temp protrusion of the cytoplasm where it flows into protrusion or engulfs prey. High energy required.

Osmoregulation in unicellular eukaryotes

pump H2O out of cell with proton pumps in membrane by transport of H+ and HCO3- into contractile vacuoles then H2O flows in to balance osmosis.

Basics of Porifera

differentiated cells (cellular- cell tissue), Radial, Sessile, Draw water in and filter.

Basics of unicellular eukaryotes

protoplasmic, microscopic, all symmetry, highly diverse, complex life cycles, no germ layer.

Habitat of Porifera

low productivity environments (low energy), few freshwater due to osmotic pressure making it energetically expensive. Add structure to environments.

Types of Porifera

Asconoid, Synconoid and Leuconoid

Asconoid Sponge

Small, simple, tube with choanocytes inside, H2O goes through tube then smaller tubes.

Synconoid Sponge

Surface dipped and changed to increase SA.

Leuconoid Sponge

Large, pockets of choanocytes and incurrent/excurrent exchange.

What sponges are made up of

Internal system of pores and canals. Collagen skeleton with spicules or chemicals to deter predation. No nervous system.

Porifera reproduction

Asexual by budding or fragmentation. Sexual via external fertilisation (water becomes medium for transportation). Monoecious. Free swimming larvae that develop onto choanocytes.

Porifera digestion

filter feeders. Choanocytes capture food (marine detritus)- flagella beat into pores. Food moves around body by phagocytosis in vacuoles.

Basics of Cnidaria

Diploblastic, Radial/bilateral, incomplete gut, cell tissue- tissue organ, acoloemate, interdeterminate cleavage, colonial & active predators)

Reproduction of Cnidaria

Asexual reproduction - budding from polyps
Sexual reproduction - fertilized eggs give rise to mobile, planktonic forms

Nematocysts

cells that line the tentacles filled with poisens/ stinging chemicals for capture of prey.

Classes of Cnidaria

Hydrozoa, Scyphozoa, Cubozoa, Anthozoa

Hydrozoa

Asexual polyp and sexual medusoid stages in lifecycle. Colonial stage.

Scyphozoa

typical jellyfish, thick mesoglea, low productivity environments.

Cubozoa

square shape from above, medusa dominant (ex. box jellyfish)

Anthozoa

sea anemones and corals

Medusoid

jelly fish shape.

Polyp

The sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other

Mesoglea

in cnidarians, the jellylike material located between the ectoderm and the endoderm--\> aids in movement and functions as hydrostatic skeleton.

Sense organs in Cnidaria

statocysts (gravity) and ocelli (light) linked to simple nerve net.

Respiration in Cnidaria

No respiratory system, simple circulation

Digestion and excretion in Cnidaria

extracellular digestion in gastrovascular cavity, intracellular in gastrodermal cells. No excretory system.

Muscles in Cnidaria

epitheliomuscular cells.

Basics of Platyhelminthes

Triploblastic, Acoloemate, Bilateral, tissue-organ

Triploblastic

has three germ layers: the ectoderm, endoderm, and mesoderm.

Respiration of Platyhelminthes

No specialised circulatory or respiratory systems - diffusion directly to cells.

Sensory systems in Platyhelminthes

Cephalisation, well developed nervous system (anterior ganglia and longitudinal nerve cords connected by lateral). Statocysts, ocelli, auricles on lateral anterior extensions. Chemoreceptors.

Gut of platyhelminthes

incomplete and branched. Lined with flamed cells which are a network of pores for excretion (under pressure gradient).

Turbellaria

Free-living, common flatworm.

Monogenea

parasitic fish flukes with simple lifecycle

Cestoda

Tapeworms, parasitic, complex lifecycles with no digestive system, reduced sensory systems and increased reproductive capacity.

Trematoda

digenetic parasitic flukes. gut with 2 branches. complex lifecyles.

Basics of Annelids

Organ system, coloemate, bilateral, protostome, complete gut.

Respiration in annelids

through skin, gills or parapodia. Respiratory pigments present (Aid in low O2 environments), closed circulation with muscular pumping blood vessels, aortic arches and capillaries.

Parapodia

false feet in Annelids.

Function of Coloem in Annelids

hydrostatic skeleton and transport function- allows outer circular and inner longitudinal muscles to shorten and lengthen sections of body.

Nephridia

excretory organ of an annelid that filters fluid in the coelom. capillary network around creates pressure gradient.

Gut in annelids

special regions for extracellular food breakdown and absorption.

Sensory systems in Annelids

ring brain (cephalisation and metameric segmentation), photoreceptors, statocysts, tactile organs, chemoreceptors. Double ventral nerve cord (pair of ganglia and lateral nerves in each segment).

Adaptations to terrestrial environments

Conserving H2O (activity in moist environments, produce dilute urine with ammonia as main waste product)
Gametes desiccating (internal fertilisation and shelled eggs)

Advantages and disadvantages of shelled eggs and internal fertilisation.

Eggs resistant to desiccation, but fertilisation capacity reduced resulting in high investment in few young.

Basics of Mollusca

Organ system, Bilateral, Triploblastic, coloemate, complete gut.

Circulation of Mollusca

low pressure with no capillary system (relies on diffusion), Open circ. Blood pushed to heart by front of body then wafts through the rest of the body cavity.

Visceral Mass

where most organs are located

Head/foot in molluscs

orientation, feeding, circulation, locomotion

Shell in mollusca

protection and stiffening (reduced or absent in some species).

Mantle in Mollusca

shell secretion, respiration by lungs/gills

Molluscs are limited by...

humidity and calcium

Nerve system in Molluscs

cephalisation: complex with ganglia and nerve cords. Ring brain around oesophagus, sense organs \= statocysts, ocelli, chemoreceptors.

Circulation in Molluscs

Open (except for cephalopods), 3 hearts.

Radula

Teeth like structure, in all molluscs (reduced in some) for scraping food.

Bivalva

Class of mollusca. 2 shelled sedentary suspension feeders. Dioecious, external fert, head and foot reduced for sedentary lifestyle. Gills and Mantle cavity is large as filtering \= primary function.

Polyplacophora

Chitons (intertidal grazers), metameric segmentation (dorsal plates). Gills in mantle.

Gastropoda

Snails. Most diverse, shell coiled or conical.

Subclass Pulmonata

Land snails, no gills, mantle has formed lung (breathe through pneumostone) Inactive during dry periods. Shell limits evaporation. No impermeable integument. Complex sexual behaviour.

Cephalopoda

Class of mollusca. squid, octopus, nautilus. Active predators, foot becomes tentacles, seperate sexes and complex courtship, loss of shell for deep sea (dissolve + pressure).

Octopus

benthic, specialised tentacle for fertilisation, no internal shell, courtship derived, short lived.

Nautilus

Chambered external shell for buoyancy (filled with air). Foot divided into 60-90 tentacles for scavenging lifestyle. Siphon pumping aids locomotion. Mantle contraction expels water from funnel.

Squid

Fast moving pelagic predators. streamlined and swim with jet propulsion. Muscular contractile mantle. suckers. powerful beak. large high resolution eyes.

Active predators need:

fast movement, coordination and prey handling equipment.

cephalopod adaptations for fast movement

high metabollic rate, efficient respiration and digestion (beak, gills and active circ of water). Closed high pressure system. 3 hearts.

cephalopod adaptations for Coordination

well developed nervous and sensory system

cephalopod adaptations for prey handling

tentacles, suckers and hard beak.

Basics of Nematoda

protostomes, bilateral, pseudocoloemates, hydrostatic skeleton, no segmentation. Ecdysozoa.

Cuticle of Nematodes

thick non-cellular collagen. contains hydrostatic pressure by fluid in pseudocoloem. 4x moults. In unfavourable conditions it doesn't shed.

Muscles in Nematodes

longitudinal but no circular, which means that muscle contraction results in more thrashing (sinusoidal) than a smoother wormlike movement

Digestion in Nematodes

complete gut. passive digestion by pressure. muscular pharnyx sucks food in. movement aids digestion.

Nervous system in nematodes

ring of nerve tissue and ganglia around pharynx. dorsal and ventral nerve cords (2x).

Hydrostatic skeleton in Nematodes

muscle contractions with movement press on fluid so forced to the opposite side when longitudinal constrict focring expansion of cuticle. when muscles relax, cuticle does so.

Ecdysozoans

protostomes that secrete and shed external cuticle. cleavage pattern, sexual reproduction. anti-HPR in neurons.

Benefits of cuticle

protection, flexible, structure, no minerals required to create, reduces water loss, muscle attachment for locomotion, forms wings in adult insects.