Download FIGURE 18.1

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
What are the Common Body Patterns and
Components in Animals?
• Grades of Organization: protoplasmic (protozoans), cellular
(metazoans, incl. sponges), cell-tissue (eumetazoans, incl.
cnidarians), tissue-organ (flatworms), and organ-system (others)
• Symmetry: asymmetrical (sponges), spherical (some protozoans),
radial (cnidarians), biradial (ctenophores), pentameral (echinoderms), bilateral (others; w/ cephalization: differentiation of a head)
– Bilateral Planes: sagittal, transverse (cross-section), and frontal planes
• Morphological Terms: anterior/posterior, dorsal/ventral, medial/lateral,
proximal/distal, pectoral, pelvic; oral/aboral (radial forms)
• Body Cavities: Acoelomate: mesoderm fills blastocoel; Pseudocoelomate: mesoderm lines outer edge of blastocoel; Coelomate:
body cavity lined entirely with mesoderm (peritoneum); true coelom
formed via schizocoelous or enterocoelous development
• Complete Gut Design and Segmentation: complete (one-way) gut
allows efficient digestion; segmentation allows greater mobility
• Components of Metazoan Bodies: epithelial, connective, muscular,
and nervous tissues
Table 9.1
Fig. 9.1
Fig. 9.2
Fig. 9.3
Figures 9.4 and 9.5
Fig. 9.6
Fig. 9.7
What is the Linnaean System of Taxonomy?
• Levels of taxonomy: Kingdom, Phylum (or Division); Class;
Order; Family; Genus and Species
– Today, all levels are intended to reflect evolutionary relatedness
– Developed by Carolus Linnaeus (mid 1700s), a Swedish botanist
• Binomial Nomenclature (Linnaeus, 1758)
– Each species receives a unique scientific name in Latin (common names
differ by location and change over time)
• Latin is a dead language (will not change), and is used internationally
– Scientific names always two words (Genus species), always underlined or
italicized (versus longer description in Latin); second name not used alone,
lower case, often describes location species found or in honor of person
• Tomato (pre-Linnaeus): Solanum caule inermi herbaceo, foliis pinnatis incises
• Descriptions of Newly Discovered Species
– Often identified based on their physical structure (Morphological Species
Concept); taxonomists attempt to include genetic comparisons and
ecological descriptions also (e.g., habitat)
– Holotype and Paratypes: first known specimen and subsequent specimens
described in peer-reviewed scientific journal
Table 10.1
Figures 10.2 and 10.3
How are Phylogenetic Relationships
• Clade: an ancestral species and all of its descendents (a
“branch on the Tree of Life”)
– Cladistics: systematic analysis of clades and their relationships to
other clades; focuses on the evolutionary innovations that define
branch points in evolution (synapomorphies: shared, derived traits)
• Parsimony: convergence considered more rare than homology; tree that
results in fewest number of steps considered most parsimonious
• Techniques
– Often heavy computer memory requirements for statistical tests
(bootstrapping, Monte Carlo simulations, tests of monophyly)
• If multiple trees result with equal significance, relationships remain
unresolved (a “bush”)
• Any single resulting tree still considered a hypothesis; best if consistent
with other independent evidence (e.g., the fossil record)
– Character states entered for multiple traits (ex. horns present = 1,
horns absent = 0); taxa that share more homologies considered
more closely related; nucleotide or amino acid sequences often
used (eliminates potential bias in choice of characters)
Fig. 10.4
Fig. 10.11
Fig. 10.6