1. Animal Architecture Flashcards
What is a bauplan?
Body plan
An assemblage of morphological features shared among many members of a phylum level group
How many animal phyla are there?
34
Describe the free living part of the phylum Platyhelminthes.
Free-living flatworms Mainly aquatic, or interstitial fauna among wet rocks/ sands, or below logs and leaf detritus Body covered by ciliated epidermis 4500 spp. May be polyphyletic
What does polyphyletic mean?
Derived from more than one common evolutionary ancestor, so not same taxon
Name and briefly describe 3 classes of obligate parasites from the phylum Platyhelminthes.
Monogenea: fish and amphibian ectoparasites
Trematoda: parasitise flukes
Cestoda: tapeworms
Describe the class Monogenea.
Fish and amphibian ectoparasites Monogenetic flukes Covered by tegument Oral sucker reduced or absent Pro- and opist- captors present 1100 spp.
Describe the class Trematoda.
Parasitic flukes Digenetic flukes Body covered by tegument One/ more oral suckers Haptors absent 2 or 3 hosts Endoparasitic 11000 spp.
Describe the class Cestoda.
Tapeworms Covered by tegument Scolex and strobila of proglottids- "segments" Digestive tract absent 2/3 hosts Endoparasitic 3400 spp.
What is segmentation and what does it allow?
A repetition of structural units
Allows for specialisation of segments by modifying them for different functions
What are homeotic mutations?
Mutations that transform parts of the body into structures appropriate to other positions
What is the origin of the anterior-posterior body plan?
Starts already in the egg
Specification of the head and posterior end by gradients of morphogens
What genes determine the differentiation of embryonic segments?
Hox genes
Is the function of important regulatory proteins conserved across species?
Yes
Describe protostomes.
Blastopore becomes mouth
Anus forms secondarily
Coelom form by splitting
Schizocoelous
Describe deuterostomes.
Blastopore becomes anus
Mouth forms secondarily
Coelom forms from out pockets
Enterocoelous
