Biodiversity Unit 1

comparative and predictive

Evolution is the unifying theory in biology, and model organisms are informative because somewhere down the line, humans have a common ancestor with model organisms.

A phylogenetic tree is a diagrammatic reconstruction of the evolutionary history of species, populations, and genes.
It is a map that shows the evolutionary history of organisms all with a common ancestor.

the common ancestor of all organisms in the tree

timing of splitting events

one or more populations of an organism or organisms

represent an ancestor and ALL of its evolutionary descendants

two species that formed when one species splits during evolution

closest relative of another unit

species will one common ancestor

lineage that undergoes cladogenesis which is branching evolution, allowing a species to later trace back

arbitrary

The largest clade is the entire phylogenetic tree.

it is what allows us to make predictions about everything from genetics & physiology to behavior & ecology

any features shared by two or more species that have been inherited from a common ancestor.

the trait that was originally present in the ancestor of a given group
it may be retained or changed in the descendants of that ancestor.
Ex- birds may have feathers, but there are so many groups of birds. Couldn't that trait of having feathers been retained OR on the other hand. Changed in the descendants of feathered birds? Birds branch out into so many different groups and species! So feathers would be an ancestral trait.

a trait that is present in a organism but was absent in the last common ancestor (the root or node) of the group being considered
Ex- the trait was DERIVED just think- DERIVED aka almost as if it was DEVELOPED NEWLY from what was seen in the last common ancestor.

Shared derived traits (not ancestral)

superficially similar traits. not actually derived traits due to a shared evolutionary history.
For example, the wing bones of birds and bats are homologous (shared by two species and inherited from a common tetrapod ancestor) but the wings themselves of bats and birds are not homologous because they evolved independently from the forelimbs of different nonflying ancestors. They have different ancestral origins but have developed similar features coincidentally or superficially.

The evolutionary process wherein a population of species DIVERGE into two or more descendant species, resulting in once similar or related species becoming more and more dissimilar.

a character trait that reverts from a derived trait back into an ancestral trait.
For example, derived limbs in terrestrial tetrapods evolved from the ancestral fins of their aquatic ancestors. Then when mammals such as whales and dolphins returned to the ocean, their limbs evolved into fins overtime, resembling their ancestral state. The superficial similarity between cetacean fins (fins on whales and dolphins) and fins on fish does not suggest a close relationship between these groups. Instead the similarity is there only because of evolutionary reversal. So they're due to evolutionary reversal, AND they're analogous traits and homoplasies.

Similar traits generated by convergent evolution and evolutionary reversals.
Homoplasies are analogous characteristics.
For example, the fins on dolphins and whales would be considered a homoplastic trait or homoplasy because the trait arose from evolutionary reversal. Wings between bats and birds would be considered a homoplasy as well because they're superficially related and not due to a common ancestor.

traits that are similar, but not due to a common ancestor.
Ex. wings of moths, chickens, and penguins, birds and bats. Like fins between whales/dolphins and fish- not homologous.

a trait that is shared by two or more species.

The ingroup is the set of taxa which is hypothesized to be more closely related to each other. Thus, taxa in the ingroup are sister groups of each other.
An outgroup is a group of organisms that serves as a reference group in determining the evolutionary relationships of the ingroup.
It is needed to construct a phylogeny to determine common ancestors.

Clades are supported by synapomorphies because it is the shared derived traits that relate one species to the other.

Phylogenies are constructed with shared derived traits as well as ancestral traits.

derived, NOT shared

Includes most recent ancestor and ALL ITS DESCENDANTS

Does NOT include common ancestor

does not include ALL the descendants from common ancestor.

-4.8 billion years ago
-Earth was molten- it was a big ball of fire, no solid rocks.
-Solar system was forming
-Water may have come from frozen comets
-The formation of earth
-The first oceans appeared here.

-The origin of life starts here
-LUCA could have originated here- and could have used glycolysis. So glycolysis is the ancestral metabolic pathway because it does not require oxygen.
-Anaerobic life dominates the biosphere- so there are living creatures that are anaerobic
-There was a reducing atmosphere, methane.
-Very first evidence of life forms, microfossil evidence from this period- they were anaerobic
-This era had NO OXYGEN, so the skies were orange and the seas were green

-Certain bacteria found a way to split water apart and make oxygen!
-The oxygen reacted with iron to make insoluble banded iron oxide
-Banded iron formations called stromatolites, which come from this period, are the earliest evidence of photosynthesis.

-No organisms could do photosynthesis. They were all anaerobic. Until one microbe figured out how to split water in half and make oxygen.
-Oxygen starts to escape from under the sea floor and reacts with everything and all anaerobic forms of life start to die. Only organisms that could do oxidative phosphorylation could survive the oxygen rich environment. This is the GREAT OXYGENATION EVENT and the FIRST POLLUTION CRISIS ON EARTH.
-Only organisms that were able to metabolize oxygen could survive.
-This period had the first possibility of anoxygenic photosynthetic cells and had the earliest stromatolites, which are this biofilms made up of cyanobacteria (banded iron formations (stromatolites) are the earliest evidence of photosynthesis.
-Cyanobacteria are present in stromatolites, which leads to the production of an oxidized atmosphere.
-Cyanobacteria were a major part of helping to oxidize the iron of the seas and lead the way to the accumulation of free oxygen in the atmosphere.
-Origin of photosynthesis
-First colonial cyanobacteria
-First eukaryotes
-First photosynthetic eukaryotes
-First multicellular eukaryotes and their fossils

-First fossils of multicellular organisms
-The phanerozoic era is basically the proterozoic era to the cenozoic era. First fossils of multicellular organisms
The phanerozoic era is basically the proterozoic era to the cenozoic era. It is comprised of the paleozoic, the mesozoic and the cenozoic



The precambrian refers to the era before the cambrian explosion. It had soft bodies species and other aquatic life. Precambrian life was small and aquatic. The precambrian era is comprised of the HADEAN, ARCHEAN, AND PROTEROZOIC periods.
-The paleozoic era had cambrian, ordovician, silurian, devonian, carboniferus, permian periods
-The mesozoic era had triassic, jurassic and cretaceous periods.
-Cenozoic era had the tertiary period.
-The pre-Cambrian refers to the era before the Cambrian explosion. It had soft bodies species and other aquatic life. Precambrian life was small and aquatic. The pre-Cambrian era is comprised of the HADEAN, ARCHEAN, AND PROTEROZOIC periods.

cambrian, ordovician, silurian, devonian, carboniferus, permian periods

Triassic, Jurassic and cretaceous periods.

the tertiary period.

the era before the Cambrian explosion. The hadean, Archaean and Proterozoic periods.
It had soft bodied species and other small aquatic life.