lecture 1 Flashcards
all living organisms are (tree of life)
related to one another and have a single common ancestor for all living organisms
what is phylogeny
the evolutionary history and relationships among or within groups of organisms
what is a phylogenetic tree?
a diagrammatic reconstruction of the history and relationship between organisms
what is there to note about the phylogenetic tree? (hypothesis)
the tree is a hypothesis based on evidence for what the true phylogeny is likely to be
what is a lineage?
a series of ancestor and descendant populations shown as a line drawn on a time axis. a population that replaces itself over time by having offspring
what is speciation?
when a single lineage divides into two depicted as a split. each descendant population gives rise to new lineage which continues to evolve.
what is a taxon?
any group of species that we designate with a name ex. genus or family
what is a clade?
group that consists of all the evolutionary descendants of a common ancestor
what is a monophyletic group?
they contain an ancestor an all descendants of that ancestor and no other organisms.
what are homologous characters
shared by 2 or more species, inherited from a common ancestor, they can be heritable traits including DNA sequences, protein structure, structures, etc
homology is evidence of
common ancestry
what is synapomorphy
characteristics present in an ancestral species and shared exclusively by its evolutionary descendants. they’re homologous characters that define a specified clade. previous evidence of the existence of a clade and all descendants have this characteristic
what are the three domains of life
eukaryotes, archaea, bacteria
what is a eukaryote?
organisms with DNA inside a nucleus
what is an archaea?
organisms with no nucleus but are molecularly different compared to bacteria
what is a bacteria?
single celled organism with no nucleus
what are the inputs of photosynthesis
CO2(from air or water), Sunlight, and H20
what are the outputs of photosynthesis
glucose and O2
what is the equation of photosynthesis
CO2+H2O–>Glucose+O2
what are cyanobacteria
ubiquitous photosynthetic prokaryotes
cyanobacteria were the first organisms to
do oxygenic photosynthesis
the rocks found in oceans are called what and a result of
stromatolites and a result of cyanobacteria creating minerals to protect themselves
starting how many years ago did oxygen levels start rising
2 to 2 1/2 million years ago
how did oxygen levels start rising on earth
billion of years of photosynthetic activity by cyanobacteria producing oxygen as a by product of photosynthesis
oxygen rich atmosphere favored what
organisms that could withstand and utilize oxygen
oxygenic photosynthesis drastically influenced what
the course of evolutionary history on earth
oxygenic atmosphere set the stage for
the rise and diversification of eukaryotes
what can cyanobacteria fix
nitrogen gas from atmosphere by using heterocysts turning it into ammonia, nitrate, nitrite
what are heterocysts
nitrogen-fixing cells formed during nitrogen starvation
