Animalia +Basal Metazoans Flashcards
(16 cards)
What does a eukaryotes organism possess
Possesses a cell nucleus enclosed within a membrane
What does a opisthokont organism possess
Possesses a single posterior flagellum
What are the descending groups in the animal kingdom
Eumetazoa - Bilateria - Deuterostomia
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Protostomia - Ecdysozoa
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Spiralia
What is the hypothetical last common ancestor of all animals
Ur-metazoan
What are the features of the ur-metazoan
- 1st multicellular animal
- eukaryotes multicellular
- flagellate
- marine
- 2 cell layers
- no symmetry
What are 3 features of basal metazoans
- either asymmetrical / radially symmetrical
- 2 layers of cells
- no organs, some differentiation of tissues
Describe the features of porifera
- sponges
- 2 layers of cells
- no tissues or organs
- no symmetry
Describe respiration + feeding in porifera
- aquifers system
- brings water through sponge, pulled in via Ostia and driven across choanderm by beating choancyte flagella at low pressures
- Water flows close to cells responsible for food gathering + gas exchange, excretory + digestive wastes expelled via osculum
What does hermaphrodite mean
Produces both eggs and sperm at different times
What are 3 ways of asexual reproduction
- fragmentation
- budding
- asexual larvae
Describe the features of placozoa
- simplest structure of all animals
- 2 layers of cells
- lower surface engulfs small particles of detritus
- reproduces via asexual budding
Describe the features of ctenophora
- radial symmetry
- 2 layers of cells
- unique colloblast cells
- swim using cilia
- bioluminescent
Describe features of cnidaria
- can be sessile, sedentary or pelagic
- bioluminescent
- symbiotic
- radially symmetrical
- diploblastic
- single body cavity
- no nervous system
- alternation of generations
What are 3 types of cnidae
- penetrant = pierces + envenoms
- glutinant = sticks
- volvent = coils around
What are 3 significant moments in embryogenesis
- morulation
- blastulation
- gastrulation
