evolution of the nervous system Flashcards
in what phylum did the nervous system first evolve
cnidarians
describe the cnidarian nervous system
simple nerve nets, though jellyfish have some level of organisation with nerve rings
describe the echinoderm nervous system
nerve nets with radial nerves on each arm, there is no obvious cluster of neurones to suggest a brain
describe bilatarians in regards to their nervous system
they have bilateral symmetry and it is here that clusters of neurones and cephalisation begins
describe the nervous system of the nematode (round worms)
they have four nerve chords, with ganglia and a nerve chord at the head
what was the first genome sequenced
C. elegans- it is easily manipulated
what mutations exist in C. elegans
rolling mutations and ‘bag of worms’
describe the nervous system of platyhelmiths (flat worms)
they have pairs of nerve chords with transverse nerves connecting them. large cerebral ganglia coincide with eye spots and sensors
describe the nervous system of annelids
they are segmented with ganglia and setae for coordinating locomation
describe the nervous system of molluscs
they are a step up in terms of coordination- particularly cephalopods where multilobed brains and developed eyes have formed
what are chromatophores
spots on the skin of cephalopods which allow them to change colour for communication and camoflage
describe the nervous system of arthropods
they have a clearly defined head, thoracic and abdominal segments and pairs of legs. they have two ventral nerve chords with paired ganglia
describe the nervous system of vertibrates
they have pronounced heads with developed brains and the nervous system is split into the CNS and PNS which communicate to regulate behaviour
what is the autonomic nervous system
subconscious reflex, divided into sympathetic and parasympathetic
what is the somatic nervous system
voluntary behaviour
