BILD 3 Chapter Notes - Chapter 10: Symbiosis, Reptile
26 Oct 2018
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BILD3 Reading Notes 10/26/18
Unit 5: The evolutionary history of biological diversity
- Symbiosis: close physiological relationship in which on species (the symbiont) lives in or on
a larger species (the host)
- How symbioses affect life on Earth
o They’re everywhere, including in humans
o Our bodies have bacteria that break down carbs otherwise not digested
o Entire ecosystems depend on symbioses. Coral reefs are built by coral polyps that
depend on energy provided by algal symbionts. Without this, coral die, harming the reef
and many fishes that live there
Chapter 26: Phylogeny and the Tree of Life
- Introduction: Investigating the tree of life
o Some organisms resemble a certain species but are not
classified as that. Biologists group organisms based on
evolutionary relationships and common ancestors
o Biologists trace phylogeny: the evolutionary history of a
species or group of species
o Reconstruct phylogenies using systematics: discipline
focused on classifying organisms and determining their evolutionary relationships
- 26.1: Phylogenies show evolutionary relationships
o organisms share many characteristics due to common ancestry. Can learn about species
based on evolutionary history
▪ organisms likely to share genes, metabolic pathways, and structural proteins with
close relatives
o binomial nomenclature: organisms named and classified through taxonomy
▪ refer to organisms with Latin scientific names
▪ use 2-part format of scientific name, called binomial
▪ 1st part is genus where the species belongs. 1nd part is the
specific epithet, unique for each species within the genus
▪ 1st part is capitalized, 2nd part isn’t. Entire name is italicized
o hierarchical classification: based on increasingly inclusive categories
▪ species -> genus -> family -> order -> class -> phyla -> kingdoms
-> domains
▪ taxon: named taxonomic unit at any level of the hierarchy
• those that are broader than the genus are not italicized, but
are capitalized
▪ placement of species into orders, classes, etc. do not necessarily
reflect evolutionary history
o linking classification and phylogeny
▪ evolutionary history of group can be represented by phylogenetic tree
▪ branching pattern often matches classifications, but sometimes species are classified
in a genus when they are not most closely related
