Lecture 7, 8/9 Flashcards
What are animal bodies distinguished by
- a tube within a tube
What does a tube within a tube mean?
-inner tube = gut
-food enters in entrance and ingested food passes to the exit
- gut lies inside larger cylinder which houses all the other stuff
about how many phyla in animal kingdom and what does it mean?
30
- own body plan that somehow varies the basic plan
- lifeforms sharing more of the pathway to LUCA = closer related and share more features
What is the Cambrian explosion?
all the living animal phyla appear in the fossil record in a relatively short time span
- explosion of many new forms
- Cambrian = geological layer in which located
Which life cycles are less varied plants or animals?
animals
what kingdom is closest to animals?
Choanoflagellates
- fungi = not primitive plants
how many vertebrate lineages are there
7
how many lineages of fish are there?
6
What are the phyla most closely related to chordates?
- hemichordate
- xenoturbellida
- echinodermata
within the chordates who are humans closes relatives?
Tunicates
- evolution of skeleton is different (spinal cord and large brain = humans unique)
What are the closest living twigs to hominids
2 chimpanzee species
Did humans evolve from chimps?
No, we just share with chimps an ancestor who lived about 7 mya
What does protostomes and deuterostomes mean?
protostomes = first mouth
deuterostomes = second mouth
means how does gut develop
What are two characteristics of lophotrochozoans
- Lophophores function in suspension feeding in adults…
- Trochophore larvae swim and may feed
All three lineages of chordates are defined by the presence of four features
- Pharyngeal slits or pouches
- Dorsal hollow nerve cord
- Notochord
- Muscular, post anal tail