Transcript INVERTEBRATE ZOOLOGY Three Domains of Life

INVERTEBRATE
ZOOLOGY
Three Domains of Life
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Three large groups called domains
Bacteria - prokaryotes
 Archaea - prokaryotes
 Eukarya - eukaryotes
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Prokaryotic – cells lack a nucleus
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Eukaryotic – cells possess a nucleus and
membrane bound organelles
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Classification is
continually changing
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Some scientists don’t
subscribe to the three
domain method of
classification
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Domain Bacteria
Some still use the Five
Kingdom method
Domain Archaea
Domain Eukarya
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Domain Eukarya
consists of several
kingdoms
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Protista - single celled
(several kingdoms)
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Plantae - multicellular
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Fungi - multicellular
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Animalia - multicellular
Protists
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
Diversity of Life
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DNA is the molecule responsible for diversity
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Specific regions of DNA (genes) code for specific types of
proteins
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Speciation occurs several ways
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Allopatric
Adaptive radiation
Sympatric
If reproductive barriers arise between populations, speciation will
occur
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Prezygotic barriers
Postzygotic barriers
Invertebrate Zoology
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Study of invertebrate animals
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Inverts make up at least 99% of all extant (living) animal species
on the planet
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Over 1,000,000 described spp. (species) on the planet (mostly
insects)
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Estimated 10 to 30 million spp. have yet to be described
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We will cover 19 (time permitting) of the approx. 35 animal
phyla
Preview of Phyla
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Protozoa – animal-like
protists
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Do not belong to kingdom
animalia, and thus are not
considered to be invertebrate
animals
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Important evolutionary link
between prokaryotes, and
everyday plants and animals
Volvox
Phylum Porifera
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Sponges
Phylum Cnidaria
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Jellyfish, Anemones, and Corals
Portuguese Man O’ War
Phylum Ctenophora
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Comb Jellies
Phylum Platyhelminthes
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Flatworms
Phylum Nemertea
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Ribbon Worms
Phylum Mollusca
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Chitons, Clams, Snails, Slugs, Squids, and Octopi
Banana Slug
Phylum Annelida
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Segmented Worms
Phylum Echiura
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Spoonworms
Phylum Sipuncula
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Peanut Worms
Phylum Tardigrada
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Water Bears
Phylum Arthropoda
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Horseshoe Crabs, Arachnids, Crustaceans,
Myriapods, and Insects
Phylum Gastrotricha
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Name means “stomach hair”
Phylum Nematoda
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Roundworms
Caenorhabditis elegans = good
Ascaris lumbricoides = bad
Phylum Rotifera
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Wheel bearers
Phylum Phoronida
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A lophophorate
Phylum Brachiopoda
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Lamp shells, another lophophorate
Phylum Bryozoa
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Bryozoans, the largest phylum in the
superphylum Lophophorata
Phylum Echinodermata
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Starfish, Brittle Stars, Urchins, and Sea Cucumbers
Phylum Chordata
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Phylum Chordata is
the only phylum
containing vertebrate
animals, however,
there are some
invertebrate chordates
Taxonomy
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Linnean system (Kingdom, Phylum, Class, Order, Family,
Genus, Species) is almost abandoned
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Genus species (binomial nomenclature) is still used
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Lumbricus terrestris
Lumbricus terrestris
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Scientists are more interested in evolutionary relationships (how
are organisms similar / different), as opposed to what “What
class do shrimp belong to?”
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Taxonomic names, and proposed evolutionary relationships
change frequently
Cladistics
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Method embraced by the authors of your text for constructing
evolutionary relationships in the form of phylogenetic trees, or
cladograms
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May be assembled according to morphology and/or molecular
data (nucleic acid or amino acid sequences)
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Can be used to infer a great deal about evolutionary relationships
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But it is easy to make mistakes
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Homology – good indication of a relationship
Analogy - misleading
Morphological Vs. Molecular Data
Body Plan Data
rRNA Data
Ground Plan
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For each Phylum we cover, you want to understand
that group’s ground plan (basic set of characteristics)
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These characteristics are useful for determining
differences / similarities between phyla
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Ground plan for Phylum Arthropoda (example):
segmented body, chitinous exoskeleton, periodic molts,
and jointed appendages