Lab 5 - Invertebrate Diversity Flashcards
Systemics
organizes life in a hierarchy based on available evidence of shared ancestry.
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Kingdom, Phylum, Class, Order, Family, Genus, Species
Binomial
genus and species group
Homo sapiens
Metazoa
Kingdom Animalia.
Monophyletic group
Ancoelomate
A body plan without a body cavity.
Each of three germ layers occur in order(ectoderm,mesoderm, then endoderm) with no body cavity between them.
Annelida
a large phylum(17,000 species) composed of segmented worms, where some organs repeat in segments.
Earthworms, leeches, polychaete worms, and others.
Arthropoda
Most diverse phylum(1million species, >80% of living species)
All members have:
- jointed appendages
- exoskeleton
- segmented body
Includes Subphylums:
- Chelicerata(spiders, scorpions, horseshoe crabs)
- Myriapoda(centipedes, millipedes)
- Hexapoda(insects)
- Crustacea(crabs, crayfish, lobsters, shrimp, barnacles, copepods)
Bilateral Symmetry
Organism with a left and right side.
Only one way to cut them in half to have matching sides.
Humans have bilateral body plan.
Chordata
Phylum of 44,000 species
Share:
- notochord(rod adjacent to nerve chord)
- pharyneal gill slits during development
- hollow dorsal nerve chord
- post-anal tail
Includes:
- all vertebrate classes(humans)
- tunicates
- cephalochordates
Cnidaria
Diplobastic Phylum 9000 aquatic species
All have stinging cells(cnidocytes)
includes:
- jellyfish
- Hydra
- Anemones
- corals
Coelomate
A body plan with a membrane lined(mesoderm) body cavity, permitting more organization than the other two body plans(acoelomate and pseudocoelomate)
Deuterostomia
A mode of development of the digestive system during which the mouth forms second(anus first).
Ecdysozoa
Organisms that molt(shed an exoskeleton and grow before the next exoskeleton hardens)
Echinodermata
A phylum of 7,000 marine species including starfish, brittle stars, sea urchins, sand dollars, sea cucumbers, and crinoids.
Ectoderm
The outer layer of tissue in the gastrula, gives rise to the skin and nervous system.
Endoderm
Inner layer of tissue in the gastrula, gives rise to most of the digestive system and multiple internal organs.
Eumetazoa
Organisms with true tissues.
Tissue organization requires major organizational, genetic, and developmental process.
Lophotrochozoa
A clade of organisms that share one of two characteristics.
- Lophophore(whorl of tentacles) mouthpart
- Trochophore(ciliated, planktonic) larval stage.
Mesoderm
The layer of germ tissue that fills the space between ectoderm and endoderm.
In triploblastic animals, the mesoderm gives rise to muscles and organs in between the endoderm and ectoderm.
Mollusca
Diverse Phylum of 93,000 species. All have a large cavity used for breathing and excretion and lined with a tissue(“mantle”), and 2 or 3 nerve chords.
Major Classes:
- gastropods(snails, slugs)
- bivalves(clams, mussels)
- Cephalopoda(squids, octopuses)
Nematoda
small, narrow worms. >80,000 species.
1/5 are parasitic
Complete gut, longitudinal muscles only
Parthenogenesis
A type of Asexual reproduction in which females produce offspring from unfertilized eggs.
Platyhelminthes
Acoelomate phylum of 20,000 species without circulatory or respiratory organs.
Many important human and animal parasites.
Parasitic classes:
- Cestoda(tapeworms)
- Trematoda(flukes)
- Monogenea
Non-parasitic groups are in Turbellaria(genus Planaria)
Porifera
Sponges.
Lack true tissues but instead are composed of different cell types.
Phylogeny under debate.
Monophyletic or paraphyletic.
