Bios 3300 Exam 1

phylogeny

a diagram depicting evolutionary relationships, shows evolutionary history

what are some other common names for phylogenies?

phylogenetic tree, tree, cladogram

tip/taxon

a formally named group of organisms, such as a species, genus, or family

nodes

branching points in a phylogenetic tree, represents ancestors, where once lineage splits into two or more descendants

sister taxa

two lineages/groups that share a MRCA and are each other’s closest relatives on a tree

internodes

space in between nodes, also called branches

root

beginning part of phylogenetic tree, connects into tree of life

does rotating nodes alter relationships?

no

does pruning a tree alter relationships?

no

polytomy

more than two descendant lineages branch off from a single node

hard polytomy

simultaneous divergence

soft polytomy

unresolved relationships

monophyletic group

all the descendants of a common ancestor, also called a clade

to make a clade, you can only ____________________________

cut a tree in one place

paraphyletic group

includes some, but not all, of the descendants of a common ancestor

what are the issues with paraphyletic groups?

classification of higher taxa needs to be based on common descent to be consistent with the tree of life and to apply to real evolutionary groups

misleads regarding relationships

homology

a trait in two or more taxa that was inherited from a common ancestor

homoplasy

similarity in the characters found in different species that is due to convergent evolution, parallelism, or reversal, not common descent

convergent evolution

similarity between species that is caused by a similar, but evolutionary independent, response to a common set of selection pressures

parallel evolution

convergent evolution within a species or between closely related species

how are convergent and parallel evolution different?

parallel evolution is at a much smaller scale, and in parallel evolution, related species can take advantage of the same developmental mechanism or gene flow

reversal

“re-evolution”, trait was lost in ancestor, but re-evolved in a later ancestor

apomorphy

a derived character

synapomorphy

shared, derived character, provides evidence of common descent

shared trait

present in two or more taxa

derived trait

changed from the ancestral condition

autapomorphy

a derived character found in only one taxon in a tree, does not provide evidence for relationships

plesiomorphy

the ancestral character state

symplesiomorphy

shared ancestral characters, a means of phenotypic similarity, but does not provide evidence of common descent when interpreting a phylogeny

what are the 3 types of similarity?

symplesiomorphies, synapomorphies, homoplasy

what type of similarity provides evidence of common ancestry?

synapomorphies

LUCA

last universal common ancestor, root of tree of life

what organisms are in the clade bacteria?

cyanobacteria and protebacteria

prokaryotes

simple, unicellular, no nucleus, no mitochonria, small cell

eukaryotes

complex, uni- or multi-cellular, have nucleus, have mitochondria, large

how do archaea and bacteria differ?

differ in details of cellular structure, protein synthetic machinery, etc

eukaryotes are ________ (or _______ is __________)

archaens, archaea, paraphyletic

what is endosymbiosis?

one cell lives within another

explain the endosymbiosis theory that led to the formation of mitochondria/chloroplasts

archaean ancestor of eukaryotes engulfs another bacteria (proteo/cyano), both benefit from this, and over time they co-evolve to be dependent on each other, the interior cell evolves to produce energy (proteo to mitochondria) or sugar from sunlight (cyano to chloroplast)

what are two pieces of evidence that support the endosymbiosis theory?

both mitochondria and chloroplasts reproduce within the cell and have their own DNA

proteobacteria

largest clade of bacteria, endosymbiont that became the mitochondria in eukaryotes

cyanobacteria (“blue-green” bacteria)

photosynthetic, first organism to release O2 into atmosphere, ancestral cyanobacteria was endosymbiont that became first chloroplast

cyanobacteria rRNA and plant _________ rRNA are sister

chloroplast

proteobacteria rRNA and plant ____________ rRNA are sister clades

mitochondria

describe “protists” and what type of group are they?

eukaryotes that are not animals, plants, or fungi, paraphyletic group

what is a synapomorphy of plantae?

chloroplasts acquired via primary endosymbiosis

what does the clade plantae include?

red algae, many aquatic groups known as “green algae,” and land plants

phycology

scientific study of algae (includes red, green, brown, and sometimes cyanobacteria), essentially everything photosynthetic that is not a land plant (paraphyletic)

red algae

mostly marine, but a few freshwater species

green plants

clade that includes land plants, but also several clades of “green algae”

“green algae”

paraphyletic, diverse, marine and freshwater

what does the clade land plants include?

mosses, ferns, gymnosperms, angiosperms

what does the clade eukarya include?

stramenopiles, plantae, fungi, animals

what are two synapomorphies of land plants?

waxy cuticle on leaves to prevent drying up, stomata on surface of leaves which are important in gas exchange

what does the clade vascular plants include?

ferns, gymnosperms, angiosperms

what does the clade seed plants include?

gymnosperms, angiosperms

what type of plants are mosses and what type of group are they?

non-vascular plant, paraphyletic group

how do mosses reproduce? briefly describe the structure of a moss

reproduce using spores (dependent on water), use alternation of generations

lack complex vascular system, so they are short

what is a synapomorphy of vascular plants?

vascular cells

vascular plants have a vascular system, which includes _______ and _________

xylem, phloem

_________ conducts water and minerals from soil

xylem

_______ conducts products of photosynthesis from the leaves

phloem

ferns

have vascular system, use spores, alternation of generations

what is a synapomorphy of seed plants?

seeds

gymnosperms

have seeds, but no flowers, includes conifers (cones)

angiosperms are also known as?

flowering plants

what are 2 synapomorphies of angiosperms?

flowers and production of fruits

what type of algae does stramenopiles include?

brown algae

how did brown algae evolve? how did its chloroplasts evolve?

independently evolved from red and green algae

chloroplasts evolved via endosymbiosis with a red algae

what does the clade ophisthokonts include?

fungi and animals

what is a synapomorphy of ophisthokonts?

flagellum located in posterior portion of the organism

how do fungi eat/get food? (synapomorphy)

absorptive heterotrophy - digest food outside their body and then absorb the nutrients

how do lichens evolve?

evolve when fungi form symbiotic relationship with a photosynthetic partner (green algae or cyanobacteria)

what are the synapomorphies of animals? (broad answer)

most are cellular details or molecular evidence

the MRCA of animals was probably ___________ and looked like a _________________

unicellular, choanoflagellate

what does the clade animals include?

sponges, ctenophores, cnidarians, bilaterians

sponges

made of cells called choanocytes assembled into an organism

filter feeders

no complex nervous, digestive, circulatory systems, no true tissues/organs

ctenophores (“comb jellies”)

radial symmetry, have a nerve net, swim with cilia, small amount of species but abundant

what type of organisms does the cnidarian clade include?

jellyfish, sea anemones, corals (marine)

cnidarians

have one opening into the gut, carnivores: use nematocysts to capture prey

what does the clade bilaterians include?

protostomes and deuterostomes

what is the synapomorphy of bilaterians?

bilateral symmetry as an embryo

triploblastic

have three embryonic cell types: endoderm, mesoderm, and ectoderm

blastopore

indentation formed during gastrulation that either becomes the mouth or anus

what does the clade protostomes include?

arrow worms, lophotrochozoans, ecdysozoans

what does the blastopore form in protostomes?

mouth

what does the blastopore form in deuterostomes?

anus

arrow worms

small marine predators, about 180 species

what does the clade lophotrochozoans include?

flatworms, annelids, mollusks

what does the clade ecdyzoans include?

nematodes, arthropods, insects

what is a synapomorphy of ecdyzoans?

have outer layer called cuticle that proves support/protection, but must be shed in order to grow

what does the clade deuterostomes include?

echinoderms, chordates

what does the clade echinoderms include?

sea stars, sea urchins, sea cucumbers

what are 2 synapomorphies of echinoderms?

external skeleton and water vascular system that includes tube feet

what are 3 synapomorphies of chordates?

dorsal hollow nerve cord, post-anal tail, notochord (largely replaced by vertebrae during development in more advanced vertebrates)

what does the clade vertebrates (/gnathostomes) include?

chondrichthyans, actinopterygii, coelacanths, lungfishes, tetrapoda

what is a synapomorphy of gnathostomes?

jaws

what is a synapomorphy of bony vertebrates?

bony skeleton

what is the group sarcopterygii also know as?

lobe-limbed vertebrates

what is a synapomorphy of tetrapoda?

4 legs