Patterns Flashcards
What is the difference between aggregative and clinal multicellularity?
- aggregative: unrelated unicellular organism come together
- clonal: are related (buds that fail to separate)
what are the potential advantages of multicellularity?
- resistance to environmental stress (e.g. outer cells protect inner cells from UV)
- in terrestrial: formation of stalk allowing elevation from the substrate and wind dispersal of the propagules
- resistance to predators
- cooperative feeding
- division of labour
- formation of a mileu interieur
what happens when multicellularity breaks down?
cancer formation (it is a feature of multicellularity)
what is adaptive radiation?
evolutionary divergence of members of a single phylogenetic lineage into a variety of different adaptive forms over a relatively short interval of geological time
what are the different adaptive radiations that occurred throughout time?
- cambrian
- silurian
- devonian
- carboniferous
- jurassic
- cretaceous
- paleocene
what happened during the cambrian explosion?
- gave rise to animals (all the phylas that exist today)
what happened during the silurian period?
gave rise to land plants
what happened during the devonian period?
radiation of fishes
what happened during the carboniferous period?
- appearance of early reptiles
- development of amphibians and insects
what happened during the jurassic period?
- rise of giant dinosaurs
- appearance of first birds
what happened during the cretaceous period?
- first flowering plants
- extinction of dinosaurs
what happened during the paleocene period?
- radiation of primitive mammals
what happened during the ediacaran period?
- first multicellular-type organisms appeared
what are the ediacaran biotia? what type of organisms were they?
- they were soft-bodies organisms
- charniodiscus
- rangea
- dickinsonia
- ediacaria
- edicaria flindersi
what anatomical features did the edicaran biota have?
they have no features (no eyes, mouths, anuses, intestinal tracts, or locomotory appendages)
were edicaran’s plants or animals?
animals
what are the different cambrian animals from the Burgess Shale of BC, Canada?
- hallucigenia
- wiwaxia
- pikaia
- opabinia
- anamalocaris
Hallucigenia is the stem taxa of which phyla?
onychophora
anomalocaris is the stem taxa of which phyla?
arthropoda
opabinia is stem taxa of which phyla?
arthropoda
wiwaxia is stem taxa of which phyla?
annelida
pikaia is stem taxa of which phyla?
chordata
what is the gould’s hypothesis of the ediacara and burgess shale phylogeny?
they are seperate (ediacara is seperate branch that went extinct)
what is conway morris’s hypothesis of the ediacara and burgess shale phylogeny?
ediacara are decendants of burgess shale (correct one)
what are molecular clocks?
the correspondence between the rate of mutation/DNA differences and millions of years (use graph that is million of years vs number of nucleotide substitutions to make tree)
what is an assumption of molecular clocks?
that mutation rates are all the same
what are the hypotheses for the cambrian explosion?
- explosion: origin and radiation occur together
- slow fuse: origin first, then radiation later
- slow: origin and slow diversification
what caused the Cambrian explosion?
- geological condition (temperature, new niches)
- rising oxygen levels
- predator-prey relationships
- developmental toolkit of genes (genes that are highly conserved)
what is the engrail gene?
codes for segment polarity
what is the Pax6/eyeless gene?
codes for eye development
what has emerged as a central mechanism explaining developmental and evolutionary change?
gene regulation
what are the three kingdoms of multicellular organism?
plants, fungi, animals
animals are hypothesized to have evolved from what organism?
choanoflagellates
how do animals obtain their energy?
eating (they are heterotrophs)
what do animals cells secrete?
extracellular matric that consists of collagen, integrins, glycoproteins, and proteoglycans
what are parazoa vs eumetazoa?
- parazoa: no true tissue (sponges)
- eumetazoa: have true tissue
what is radiata vs bilateria?
- radiata: radially symmetrical
- bilateria: bilaterally symmetrical
what is prorostomia vs deuterostomia?
- prorostomia: envagination in early embryo becomes mouth
- deuterostomia: envagination in early embryo becomes anus
what is lophotrochozoa vs ecdysozoa?
- lophotrochozoa: have lophophores, which is a set of ciliated tentacles surrounding the mouth
- ecdysozoa: shed skin (worms, crustaceans, insects)
what did plants evolve from?
green algae
plants have ____ rich cell walls.
cellulose
how do plants get their energy?
sun (photoautotrophic)
how did green algae get new genes an evolve into multicellular photosynthetic organisms?
got new genes through horizontal gene transfer and gained organelles by endosymbiosis
what are the similarities between green algae and land plants?
- store carbohydrate reserve as starch
- have rigid, cellulose-reinforced cell walls
- use similar types of pigment in metabolic pathways, both chlorophyll a and b, and carotenoids alpha and beta
what makes plant reproduction so special?
they go through alternation of generations (between haploid and diploid phase)
what are the 4 major evolutionary inventions in plants (and what are the associated type of plant)?
- bryophytes and hepatophytes: non-vascular lineage (moss…)
- ferns and other seedless vascular plants: vascular lineage
- gymnosperms: seed lineage
- angiosperms: flower linage
why did angiosperms evolve so rapidly?
their flower structures enabled insects or birds to pollinate them and disperse there seeds
how do fungo obtain nutrients?
either from live host by parasitism or from the digestion of dead organic matter (absorb nutrient from their substrate – release digestive enzymes)
what is said to be the ancestry of fungi?
- share a choanoflagellate ancestor with animals, so more closely related to animals than plants, are sister group to animals
what are the cell walls of fungi composed of?
chitin
