Invertebrate Zoology Bio 370 Introduction

1. Invertebrate Zoology � Bio 370 Introduction Meetings: Lecture T,Th 9:30-10:45Lab/discussion Th 6-8:50 Textbook: Brusca & Brusca Course Content Biodiversity Phylogeny Comparative Biology

2. Slices = taxonomic categories, e.g. �molluscs� Layers = functional disciplines, e.g. �ecology� or �behavior� The Layer Cake of Biological Disciplines

3. Taxonomic categories Botany Zoology Malacology Entomology Arachnology Ichthyology Ornithology etc.

4. Functional categories Physiology Ecology Genetics Parasitology etc.

5. Many biologists study one functional aspect of one taxon

6. � These disciplines are artifacts of convenience and history. They give psychological support to us by setting limits on what we are supposed to know and limits to what we have to think about. They often achieve a kind of institutionalized immortality, and they also obscure our view of biology.� Bartholomew, 1982 �

7. Invertebrate Zoology: most of the cake! Jean Lamarck Father of Invert Zoo & author of first text Systeme des Animaux sans Vertebres 1801 Curator of �inferior� animals at the Paris museum

8. Lamarck, continued Early evolutionist Studied fossil molluscs of Paris Basin and concluded that species had changed over time (evolved). paved way for Darwin & Wallace (1854).

9. Comparative Biology Taxon as an experimental variable Comparison of biological structures & functions across taxa. Structures and functions have evolved and can be better understood by comparing different organisms. Taking phylogeny into account�two things can be the same for 2 different reasons�.

10. Example of comparative approach Biologist #1 determines that normal human blood pH is 7.4. Biologist #2 studies lizards and fish and finds that blood pH is regulated at higher values when their body temperature is lower. Which biologist will have best insight on how to regulate pH during hypothermic surgery?

12. August Krogh Respiration physiologist, winner of Nobel Prize (1920) Krogh�s Principle: �For a large number of problems there will be some animal of choice on which it can be most conveniently studied�

13. Examples of Krogh�s principle Neurophysiology: squid (Loligo) Genetics: Drosophila (fruit fly) Development: Caenorhabditis (nematode) Estivation: Artemia (brine shrimp) Indicator fossils: e.g. conodonts, trilobites

14. Biodiversity The number and variety of organisms found within a specified geographic region. The variability among living organisms on the earth, including the variability within and between species and within and between ecosystems.

15. Biodiversity and conservation Conservation Biology: a multidisciplinary science that has developed to deal with the crisis of declining biological diversity. MDC Fisheries Division: primary goal is �preservation of biodiversity�

16. How can we measure biodiversity? Biological description and classification(taxonomy and systematics):each species is formally described and its relationships with others are hypothesized Biogeography, faunal, floristic and distributional studies..�bioassessment�which species live where in terms of geography and habitats

17. Bio 370 Biological classification Taxonomy = naming of species and other taxa according to rules International Commission of Zoological Nomenclature (since 1895) ICZN Systematics = the classification of organisms into taxa Phylogeny = the evolutionary relationships among taxa

18. Biological classifications have two different purposes To group kinds by similarity(this is what functional categories do) To describe phylogeny 

19. Two kinds of similarities Homology =similarity that results from shared inheritance. Analogy = similarity that results from convergent evolution. Only homologies can be used to infer phylogeny

20. Classification frameworks Phylogenetic classification grouping nearest relatives (=descendants of a shared ancestral species) Functional classificationsgrouping by similarity regardless of homology Traditional taxonomic classifications are a little bit of both

21. Bio 370 Examples of functional classifications By habitat Marine, troglobytic, thermophilic, etc. By physiology, anatomy, behavior Endotherm, bipedal, social By trophic relationships Predator, herbivore, autotroph, etc

22. Phylogenetic systematics Traditional classifications often based on similarity of selected features, and do not always reflect phylogeny. Today, most biologists feel that taxonomic classifications be based only on phylogeny.

23. Bio 370 Biological classification Taxonomy = description, naming, and classification of species and higher taxa. Systematics = classification of taxa according to genealogical relationships. Phylogeny = the genealogical relationships of organisms. Modern biological classifications are hypotheses about phylogeny.

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25. Bio 370 Taxonomic categories (ranks) Domain Kingdom Phylum Class Order Family Genus Species

26. Bio 370 Genus contains 1 or more species Family contains 1 or more genera Order contains 1 or more families, etc. You should know the categories and the taxa in the first two (domains and kingdoms) Higher taxonomic categories are more inclusive

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28. Kingdom Phylum Class Order Family Genus Species

29. Bio 370 Includes all the descendants of the shared ancestor of the group.�� Also called a clade.

30. Bio 370 Includes parts of two or more clades (some but not all of the descendants of two or more different ancestors). This classification could result from mistaking analogy for homology.

31. Bio 370 Includes some, but not all, of the descendants of a common ancestor. e.g. �Invertebrata�, leaving out the vertebrate chordates.

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33. Bio 370 Phylocode (link to Phylocode website) Proposed as replacement for traditional system of ranked taxonomic categories Just two categories: clades and species. �Species" and "clade" refer to different kinds of biological entities, not ranks Clades are named but not ranked except in a relative sense � big clades contain other, smaller clades.

34. Bio 370 Phylocode, continued �A species is a segment of a population lineage, while a clade is a monophyletic group of species. Both are products of evolution that are discovered, rather than created, by systematists, and both have an objective existence regardless of whether they are named.�

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40. Highest taxonomic classification of organisms: domains

41. Domain and Kingdom classification Archaea Bacteria Eukaryota Protista Fungi Animalia Plantae

42. Traditional hierarchy plus domain DomainKingdom Phylum Class Order Family Genus Species

43. Kingdom Animalia Animals are defined as multicellular heterotrophic eukaryotes lacking cell walls. 80% of described species are animals. Animals are classified in about 33 phyla in modern classifications.

44. Diversity in animals, continued Vertebrates are part of the phylum Chordata. The big 8 or �major� animal phyla in terms of numbers of described species (roughly in order):

46. Kingdom Animalia, continued ~95% of animal species are invertebrate. ~80% of animal species are Arthropods. ~75% of animal species are insects. ~66% of animal species are beetles. Only ~5% of animal species are vertebrate.

48. Why are we so preoccupied with vertebrates? Most vertebrates have large body size. Humans are big, and we are more aware of organisms in our own size range. Yet, the �typical animal� is an invertebrate 1-10 millimeters long.

49. Where do animals live? (Wilson handout) Greatest diversity of phyla is in marine, benthic habitat. 12 phyla (about a third of all) are exclusively marine. No phyla are exclusively freshwater or terrestrial. Why?

50. Most species (over half) are on land, even though earth is only 2/5 land. Origin of species requires reproductive isolation. Reproductive isolation of populations is more likely on land- habitats are often more local. Dispersal is more difficult on land than in ocean. Many marine invertebrate larvae are planktonic, so that marine species tend to have large geographic ranges.

51. Bio 370 How many species are there? Terry Erwin- (Wilson handout) Craig Venter-2004 "whole genome shotgun sequencing" of microbes in water samples from the Sargasso Sea. Identified 1,800 �genomic species�, including 148 new bacterial types.

52. Bio 370 How many species are there? Current research efforts (links): Tree of Life NSF Planetary Biodiversity Inventories Example Census for Marine Life