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77 Cards in this Set
- Front
- Back
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taxon |
a groups of organisms at an unspecified level of a classification scheme |
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phylogenetic tree (evolutionary tree) |
the branching pattern on a tree represents ancestor-descendant relationships |
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cladogram |
it depicts only the sequence of splitting events |
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phylogram |
length of each branch in a tree is intened to be proportional to the amount of evolution that has occurred after the lineage splitting event |
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sister taxa |
pair of taxa resulting from a lineage split |
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extant |
living forms |
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most recent common ancestor |
is the ancestor of all group members in the time closest to the present |
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characters |
traits of organisms |
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character states |
can be "present" or "absent" or variable conditions such as size |
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Principle of Parsimony |
simplest pathway explains all the available evidence |
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homologous characters |
are present in organisms because they were inherited from a common ancestor |
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homoplasious characters |
structures with the same morphology, where the morphology is not inherited from a common ancestor |
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monophyletic groups |
groups that contain all the descendants of a single recent common ancestor |
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clades |
a rank-free classification |
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polytomy |
undefined branching pattern |
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nested hierarchy |
no limit to the number of taxa at each level in the hierarchy |
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coccus |
sphere form |
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bacillus |
rod-shaped |
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helical |
elongated, twisted rod |
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vertical transmission |
the passing of genes from haploid "parents" to "offspring" or from ancestors to descendants |
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Lateral Gene Transfer |
plasimids are one of the genetic elements that can be transferred among microorganisms; transfer of genetic material to unrelated organisms |
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transformation |
a process whereby DNA fragments from lysed cells are moved into an intact cell. The fragments are incorporated into the genome by crossing over (recombination) with the homologous region in the host. A portion of the host's original DNA is replaced by the new squence from outside the cell. (cells that can do this are 'competent') |
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Conjugation |
a form of mating, but it may occur between distantly related cells. a tube called a pilus forms between two cells. A plasmid in the donor cell replicates and one copy passes through the pilus to the recipient cell. The plasmid duplicates inside the recipient cell and the pilus breaks. |
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Transduction |
the incorporation of new genetic material into a host through the action of viral phage particles. Transducting phage particles carry DNA from one host to another. Once in the new host, the transferred DNA recombines with a homolous region of the host's genome |
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LUCA |
last universal common ancestor |
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amoeboid form |
irregular shape |
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flagellate form |
one to many flagella |
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ciliate form |
numerous short cilia in rows across the cell surface |
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gram positive |
two membranes: pep and cell membrane |
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gram negative |
three membranes: two cell membranes with pep in the middle |
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coenocytic cell |
bears numerous nuclei which are the result of multiple nuclear divisions but no cytokenesis |
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meristem cells |
plant undifferentiated cells with the potential to develop into any adult cell type |
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apical growth |
meristematic growth occurs at the tips of stems or roots |
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two cutting faces |
form sheets like the thallus of a liverwort |
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three cutting faces |
cell that can divide to add a new cell on each of these three basal sides |
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axillary meristem |
groups of meristematic cells found in the angle formed between a leaf and stem (can grow to be branches) |
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root cap |
they protect the root meristem as the root grows through the soil |
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cambium |
type of meristem that continues to divide and produce new vascular cells and tissues |
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microphylls |
leaves that possess only a single strand of vascular tissue |
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sporophylls |
reproductive leaves |
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vegetative leaves |
sterile leaves |
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simple fruits |
develop from a single ovary from a single flower |
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aggregrate fruits |
develop from flowers thst had multiple independent ovaries in a single flower |
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multiple fruits |
develop from muliplte flowers that started off as closely spaced individual fruits, but as they got bigger they grew together and fused |
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thallus |
body of a fungus |
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septa |
cross-walls that divide hyphae of fungi into individual cells |
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dimorphic |
can switch back and forth between mycelial and yeast forms |
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dikaryon |
a cell containing two haploid nuclei and is designated as n+n |
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saprobes |
decomposers of dead organic matter |
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processing guts |
have regions of the digestive tract specialized for particular functions |
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blastula |
a hollow or solid ball of cells, it is present in all metazoans |
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regulative cleavage |
the fate of the cells is not determined by the distribution of mRNAs, but by the chemical gradients produced by the cells |
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mosaic cleavage |
the distribution of mRNAs controls the fate of each cell, if a cell is lost early in development, no other cell can replace the structures that would have been made by the lost cell, so development fails |
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What are the functions of different Cnidarian life stages? |
polyp: feeds medusa reproduces and disperses |
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Key Features of Cnidarians |
Diploblastic, cnidocytes, radial symmerty |
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Key features of Sponges |
Choanocytes, spicules, no symmertry, no gut |
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Foot |
muscle used for locomotion |
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Radula |
feeding structure (scraper) |
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Mantle |
covers organs, secretes shell |
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Chitons |
segmented shell, unsegmented body |
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Bivalvia |
no radula, no head |
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Mussels |
radula is absent because bivalves use enlarged gills to suspension feed foot is reduced bilateral, but no head some have siphons which are derived from the mantle and used to move water through the shell for feeding and gas exchange |
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Chitons |
radula, foot, mantle, shell bilateral with head complete gut |
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external adaptations of the intact squid |
beak foot has become siphon (jet propulsion) and tentacles (for grabbing prey) shell has been reduced (shell pen) extremely cephalized |
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annelida |
segmented paired setae parapodia (lateral appendages extending from body segments) bilateral with head complete gut |
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arthropoda |
jointed appendages exoskeleton (ecdysis) compound eyes segments and tagmata bilateral with head complete gut |
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echinodermata |
pentaradial (bilateral larval stage) no head water vascular system |
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chordata |
post anal tail pharyngeal gill slits dorsal tubular nerve chord endostyle/ thyroid gland notochord bilateral with head segmentation (seen w/ repeating gill slits and muscle striations) |
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Tunicates |
inverbrate chordates hollow dorsal nerve cord (lost in adult tunicate) notochord (lost in adult tunicate) pharyngeal gill slits (gill basket in tunicate) post-anal-tail (lost in adult tunicate) endostyle (produces mucous in adult tunicate) |
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lancelets |
exhibit all five basic characteristics of Chordata hollow dorsal nerve cord notochord post anal tail pharyngeal gill slits (all still present at adult stage) |
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lophotrochoza |
protosomes that do not molt |
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ecdysoza |
protosomes that do molt |
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trochophore larvae |
larval form of molluscans and some annelids. they are ciliated, with cilia arranged into several bands they have a complete gut and swim around in the ocean eating smaller plankton |
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choanocytes |
cells typical of sponges. Resemble choanoflaellates they have a "collar" of microvilli with a single flagellum |
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Hexapod development |
one has a pupal stage where the larva goes into a dormant stage to metamorphose into the adult, and the other does not if there is no pupal stage, the larvae tend to resemble the adults |
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animal characteristics (synapomorphies of metazoa) |
blastular development heterotrophic multicellular produces collagen |
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general trend |
bilateral symmetry infers cephalization |
