evolution: animal diversity - part 1 biology 155 krilowicz spring 2010
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Evolution: Animal Diversity - Part 1
Biology 155
Krilowicz
Spring 2010
I. Definitions
A. Taxonomy: the science of classification of living things; older schemes were constructed without regard for evolutionary relationships among organisms
B. Phylogeny: the science that examines the evolutionary relationships among organisms; most taxonomic schemes in use today are based on phylogeny
II. What types of information can be used to construct phylogenetic
schemes?A. Anatomy: similarities or differences in structure
of modern day forms1. Adult structures –
The bones of a human arm are very similar to those in a bird wing, so probably closely related animals (homologous structures)
The vertebrate limbs are very different from arthropod limbs, so these two groups are more distantly related
Various arthropods
Various vertebrate forelimbs
Fig. 13.5A
II. What types of information can be used to construct phylogenetic
schemes? - continuedA. Anatomy: similarities or differences in
structure of modern day forms – continued2. Embryonic structure –All vertebrate embryos go through very similar
developmental patterns, so probably closely related animals
The development of vertebrates (deuterostomes) differs from arthropods (protostomes), so these two groups are more distantly related
Two vertebrate embryos at similar stages in
development
Fig. 13.5B
II. What types of information can be used to construct phylogenetic
schemes? - continuedB. Physiology: function of present day organisms
Mammal and reptile lungs function in essentially the same manner, so probably closely related animals
Insects use a tracheal system to exchange gases that functions very differently from vertebrate lungs, so these two groups are more distantly related
II. What types of information can be used to construct phylogenetic
schemes? - continuedC. Geologic (Fossil) Record: can be used to
determine –
1. Anatomy of extinct organisms
2. First appearance of currently living organisms
II. What types of information can be used to construct phylogenetic
schemes? - continuedD. Biochemical Information: how similar is
the structure of enzymes, ribosomes, etc. among groups of organisms?; Reflects similarity in DNA because information in the genes is used to construct proteins, RNA and other biological molecules
II. What types of information can be used to construct phylogenetic
schemes? - continuedE. Gene (DNA) Sequence Data – how
similar is the genetic material among living organisms? ultimately what scientists really want is an answer to this question to definitely construct phylogenetic trees
Has recently led to a reorganization of living things into three domains versus five kingdoms
Three domain system of classification
Five kingdom system of classification
III.The Taxonomic Hierarchy:
Domain (three of these)
Kingdom
Phylum (Animals) or Division (Plants)
Class
Order
Family
Genus
Species
Increased relatedness = more traits in common
Only group with a biological definition
Definition of a species
• A group of actually or potentially interbreeding organisms that are reproductively isolated* from other organisms
* Either cannot mate with another organism or mating produces sterile offspring
Species names have two parts
Genus species
Capitalized lower case
italicized italicized
Usually Latin
Example – Felis domesticus