Intro
• For a gentleman should know
something of invertebrate zoology, call it
culture or what you will, just as he ought
to know something about painting and
music and the weeds in his garden.
• Martin Wells, Lower Animals, 1968
Kingdoms of life
• Eubacteria, Archaea, Fungi, Plantae
• Protista
~ 18 Phyla
• Animalia
~ 34 Phyla
Diversity of known groups
• Kingdom Animalia
– 1,000,000+ described species
– Vert’s (~50,000)
– Invert’s and other Chordates (~ 1 million)
– Total species?
• 10-30 million
• Or 100-200 million
Phyla with most spp.
• Arthropoda ~ 1.1 million
• Mollusca ~ 100,000
• Protista ~ 80,000
Invert origins
• Life on earth: after cooling ~ 4.6 billion YA
• Eukaryotic cells: ~ 2.7 billion YA
• Shared ancestors of plants + animals:
~ 1.6 billion YA
• Metazoans: ~ 600 million YA
• Evidence?
Geological strata
• Learn major eras, periods, epochs
• (of Phanerozoic eon)
• http://www.ucmp.berkeley.edu/help/timeform.html
Cambrian Explosion?
• Major phyla first appear and diversify
• Precambrian
– Cnidaria and Porifera
Cambrian explosion
• Paleozoic
– Mollusca, Brachiopoda, Ctenophora,
Priapulida, Onychophora, Arthropoda,
Phoronida, Annelida, Echinodermata,
Chordata, Hemichordata, Tardigrada,
Nematoda, Nemertina
Phyla Brachiopoda,
Ctenophora, Priapulida
Phyla Onychophora,
Phoronida, Arthropoda
Phyla Annelida,
Echinodermata,
Hemichordates
Phyla Tardigrada, Nemertina,
Nematoda
Hookworm
Cambrian explosion
• Mesozoic
– Entoprocta, Rotifera, Nematomorpha,
Platyhelminthes, Gastrotricha,
Acanthocephala
Biomes and ecosystems
Marine ecosystems
• Most of planet is marine
• Available habitats:
– Littoral, pelagic, benthic (epifauna,
infauna), interstitial
Estuaries, coastal marshlands
• Salt marsh
• Estuary
Freshwater
• Less stable than marine
• Requires diapause, hibernation,
aestivation
Terrestrial
• Temperature extremes
• Lower diversity (except arthropods)
Evolution
• Anagenesis = microevolution causes
changes w/in species
• Macroevolution:
– Speciation = birth of a species
– Extinction = death of a species
Microevolution
• Changes caused by:
• Random genetic drift, Natural selection,
etc.
• Changes occur that result in organisms
that “fit” their environment
Macroevolution
• Cladogenesis = origins + radiations of
species lineages
• Mass extinctions
• Rapid speciation and radiation
What causes major species
radiations?
• Flexible architecture of genetic
regulation
– Developmental pathways undergo major
changes with few genetic differences
– Results in changes in body plan
– Requires flexible architecture of genetic
regulation
Classification, systematics,
phylogeny
• Review basic philosophy of systematics
Classification
• Ordering organisms into groups
• By taxa: species, genera, families, etc.
How are they grouped?
Nomenclature
• Rules for naming
• 1. Each kind of organism has only one
correct name
• 2. No 2 kinds of organism have the
same name.
Binomial nomenclature
• Linnaeus’ system
• Binomial = Genus + species
ICZN
• International Code of Zoological
Nomenclature: 1758
• Principles:
• Scientific names are Latin, valid name
based on first usage, names must be
based on type specimens
ICZN in practice
• Author who first describes species has name
following species name
Wheel bug, Arilus cristatus (Linnaeus)
• In parentheses = in different genus than
originally placed
Systematics
• = taxonomy + phylogenetics
• Study of kinds and diversity of life on
Earth, and of relationships between
them
Alpha taxonomy
• Naming species:
• Describing undescribed organisms
• Uniting multiple descriptions of same
organism
Science of systematics
• Classical science based on morphology
• Currently use embryology, physiology,
immunology, behavior, biochemistry,
molecular genetics, morphology
• Growing science
Basic terms
• Monophyletic group = includes all
descendants
• Paraphyletic group = does not include
all descendants
• Polyphyletic group = some arose from
different ancestors
Characters
• Attributes of organisms used in
comparisons
• Homology = shared common ancestor
has this character