7f Flashcards
evolutionary advantages of invertebrates
Organization of cells into tissues (and start of symmetry)
Radial vs bilateral symmetry
Protostome vs deuterostome body plan
Protostome further divided:
cuticle is moulted
Cuticle is not moutled
List the main distinguishing features of the kingdom Animalia
Multicellular
Animal cell have no cell walls
Heterotrophic
Reproduction commonly done sexually
Animals at some point are mobile
Calcification done through bilateral or radial symmetry
Distinguish between radial and bilateral symmetry
Radial - symmetry is placed four ways and the embryo hold 2 germ layers, end/ectoderm
Bilateral - place of symmetry is split two ways and embryos hold 3 germ layers, endo/ecto/mesoderm
give examples of phyla radial and bilateral symetry
Radial - Phylum Cnidarian (sea jellies, anemones, coral) and Phylum Ctenophora (comb jellies)
Bilateral - all other invertebrates.
features of Coelomates
Coelomates - digestive tract is in a cavity lined completely with mesoderm
features of Pseudocoelomates
Pseudocoelomates - body cavity is partially lined with mesoderm
features of Acoelomates
Acoelomates - no separation between body wall and digestive tract
features of Protostome development
Protostome development - ‘first mouth’ invagination at gastrula stage becomes the mouth: includes roundworms, flatworms, segmented worms, molluscs, and arthropods
features of Deuterostome development
Deuterostome development - ‘second mouth’ invagination of gastrula becomes the anus; mouth forms secondarily: includes echinoderms and chordates
Describe the main distinguishing features of the phylum Platyhelminthes
Commonly known as flatworms
Free-living or parasitic
The parasitic are two major groups (cestodes- tapeworms and trematodes - trematodes) they require primary host (digestive tracts) and secondary hosts (vertebrate or mollusc).
Reproduce asexually (regeneration of body) or sexually
Most are hermaphroditic, and can self-fertilise
Possess simple tissues: eyespots, ganglia, nerve cord
No circulatory or respiratory systems
Describe the main distinguishing features of the phylum Arthropoda
They hold an exoskeleton that is shed periodically. A segmented body with paired jointed appendages
disadvantages of the arthropod exoskeleton
Moulting can be dangerous as they are left vulnerable and it requires a lot of energy, the exoskeleton is also heavy
advantages of the arthropod exoskeleton
Protection, watertight and provides a rigid attachment site for muscle however joints are thin and flexible.
Describe speacial adaptations of the arthropoda phylum
Cuticles that prevent water loss, wings for insects and the body: head (sensory apparatus and feeding), Thorax (locomotion) and abdomen (digestion and reproduction).
Embryos contain 3 germ layers in bilateral symetry..
endoderm
ectoderm
mesoderm
