Parazoa and Radiata Flashcards
What sub-kingdom has the most simple animals?
Parazoa
What does protostomia and deuterostomia mean?
Protosomia = mouth formed before the anus
Deuterostomia = anus is formed before the mouth
What animals do not undergo gastrulation?
All animals under parazoa e.g. sponges
What do true tissue layers enable?
Specialisation
Organ development
What separates radiata from bilateria?
Symmetry
What are the differences between radiata and bilateria?
Radiata:
Oral/aboral side
Diploblastic (two tissue layers)
Tend to be sedimentary
Bilateria:
Anterior/posterior and dorsal/ventral sides
Triploblastic (three tissue layers)
Tends to lead to cephalisation and an active lifestyle
What cleavage pattern does protostomes and deuterostomes have?
Protostomes = spiral
Deuterstomes = radial or oblique
What are the differences between protostomes and deuterostomes?
Protostomes:
Cell fate determined early on
Mouth develops from the blastopore
Mesoderm splits to form coelom
Deuterostomes:
Cell fate is undetermined early on
Anus develops from blastopore
Folds of archenteron form coelom
What is the coelom and what is it for?
Space between the endoderm and ectoderm
Surrounded by mesoderm in most animals
Protects organs (due to being filled with fluid)
Allows organ growth
What are protostomes divided into?
Lophotrochozoa
Ecdysozoa
What are the main features of parazoa?
Asymmetrical
No gastrulation
No true tissues
What phylum do sponges come under?
Porifera
What are the main features of the phylum Porifera?
Simple body plan
Lack muscles, nervous system and organs
Sessile
Some specialised cells
How do Porifera feed?
Water is drawn in through porocytes
Water helped into the porocytes as the flagellum of choanocytes (specialist feeding cell) create a current
Water leaves through osculum
Amoebocytes take food from the choanocytes and transport around the body
How do the phylum Porifera reproduce?
Prefer to sexually reproduce rather than self-fertilise
One playing male releases sperm which enters the female
Fertilises her eggs which she then lays
Eggs hatch into larvae that swim around before finding somewhere to anchor and grow
May play a male one mating season and the female the next
Can bud off to form new individuals - asexual reproduction
