Please enable JavaScript.
Coggle requires JavaScript to display documents.
Evolution (Phylogeny and the Tree of Life (Organism Evolutionary History,…
Evolution
Phylogeny and the Tree of Life
How are phylogenies are inferred
Morphological and Molecular Data
organisms with similar morphologies or DNA sequences are likely to be more closely related than organisms with very different structures and genetic sequences
Homology
similarity due to shared ancestry
Analogy
similarity due to convergent evolution
Computer Programs
used to align comparable DNA sequences and to distinguish molecular homologies from coincidental matches between taxa and diverged long ago
Constructing Phylogenetic Trees
Clade
monophyletic group that includes an ancestral species and all of its descendants
distingushed by their shared derived characters
Parsimonious Tree
tree that requires the fewest evolutionary changes
based on the most likely pattern of changes
well supported with a consistent wide range of data
Organism Evolutionary History
Orthologous genes
homologous genes found in different species as a result of speciation
Paralogous genes
homologous genes within a specie that result from gene duplication
such genes can diverge and potentially take on new functions
Distantly related species often have many orthologous genes
the small variation in gene number in organisms of varying complexity suggest that genes are versatile and may have multiple functions
Molecular Clocks
a method of estimating the date of past evolutionary events based on the amount of genetic change
suggest that most common strain of HIV jumped from primates to humans in the early 1900s
Tree of Life Continuous to change
past classification systems
consist of 3 domains: Bacteria, Archaea, and Eukarya
based in part on rRNA
Horizontal Gene Transfer
the movement of genetic material between unicellular and multicellular organisms other than the transmission of DNA from parent to offspring
History of Life on Earth
Conditions of Early Earth
abiotic synthesis of small organic molecules such as amino acids and nitrogenous bases
The joining of these small molecules into macromolecules, such as proteins and nucleic acids
The packaging of these molecules into protocells
droplets with membranes that maintained an internal chemistry different from their surroundings
The origin of self replicating molecules that eventually made inheritance possible
Fossils
based largely on fossils found in sedimentary rocks
documents the rise and fall of different group of organisms over time
Radiometric Dating
sedimentary strata reveal the relative ages of fossils
Show how new groups of organisms can arise via the gradual modification of preexisting organisms
Key Events of Lifes History
Rise and Fall of Organisms
Plate Tectonics
continental plates move gradually over time, altering the physical geography and climate of earth leading to extinction in some groups and speciation in others
5 Mass Extinctions
Radically altered lifes history
Continental drift
Volcanic Activity
and impact from comets
Adaptive Radiations
large increases in the diversity of life
possess major evolutionary innovations that colonized new regions in which their is little competition from other organisms