Inverterbrates 15 Flashcards
Exam
What is an invertebrate?
Animals that lack a backbone , Example: fish
Classifying invertebrates based on evolutionary relationships.
Porifera, Cnidaria, lophotrochozoa, enysozoa
Sponges
Basal, lack tissues
Cnidarians
ancient, with tissues
Lophotrochozoans
Wide range of bodily forms
Endysozoans
most species-rich
Deuterostome
Chordates echinoderms
Phylum Porfiera: Sponges
most basic animals , lack tissues , sedentary (sessile) , mostly marine.
filter feeders flagella move water through body
Phylum Cnidaria: animals with stinging cells
defense or predation.
may release venom , some sessile others motile
Body plan: central cavity, one opening
Cnidocytes
stinging cells
specialized calls for capturing prey
goal: sting/capture prey
when triggered shoot out harpoon
Cnidarian are predators
Tentacles used to capture prey and bring to the mouth
cnidarians have tissue = contractile (movement ) and nervous tissue (to detect / respond)
Invertebrates evolutionary relationships
common ancestor of all invertebrates : sponges animals with tissues
bilateria
Animal group
Eumatozoa: all animals - except sponges
Bilateria: majority of animals
Bilateria
L/R side bilateral symmetry
3 tissue layers: endo, ecto, mesoderm
digestive tract: 2 openings
body cavity: coelom
Lophotrochozoa
Have a lophore
Crown of tentacles for feeding
surrounds mouth
ciliated
also functions in gas exchange (o2 in Co2 out)
Trochophore larvae
have cilia that function in movement and capture prey
most diverse group in bilaterians
Lophotrochoza: Phylum Platyhelminthes
Free-living or often parasitic –> tapeworms
thin/fat bodies allow for gas exchange
differ from other bilaterians
1) One opening
2) no cavity
Lophotrochozoa: Phylum Molluscs
Include: small slugs
-bivlaves>two > hinges
octopus/ squid group
soft body, usually have shell ( may be reduced)
3 Parts of Mollusc body plan
1) foot: movement or a suction cup
2) Visceral mass: contains organs
3) Mantle: fold tissues, secretes shell
Endyozoans
The most species-rich animal group
Enydsis= molting, shedding exoskeleton
Endysozoa: Phylum Arthopods
segmented body
hard outer skeleton, made of chitin
jointed appendages
sensory organs
includes insects, arachnids, crustaceans
Deuterostomes
includes some invertebrates and all vertebrates
Phylum echnoderms
-often slow-moving
- in bilateria, but have radial symmetry
