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
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
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
• Paleozoic– Mollusca, Brachiopoda, Ctenophora,
Priapulida, Onychophora, Arthropoda, Phoronida, Annelida, Echinodermata, Chordata, Hemichordata, Tardigrada, Nematoda, Nemertina
Cambrian explosion
• Mesozoic– Entoprocta, Rotifera, Nematomorpha,
Platyhelminthes, Gastrotricha, Acanthocephala
Marine ecosystems
• Most of planet is marine
• Available habitats:– Littoral, pelagic, benthic (epifauna,
infauna), interstitial
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
• 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.
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
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