Final Exam Flashcards
Deuterostomes Classification
5 living classes:
- class echinoidea - sea urchins, sand dollars
- class holoththuroidea - sea cucumbers
- class asterozoa - starfish (sea stars)
- class opichiuroidea - brittle stars, basket stars
- class crinoidea - sea lillies
class echinoidea
- skeleton made of interlocking plates, sometimes fused together
- test shape ranges from urchins to sand dollars
- show near perfect 5-fold symmetry or can be bilateral
- jaw apperatus made of 5 hard teeth arranged in a circle - aristotle’s lantern
regular echinoids mostly epifaunal grazers: some predators
-irregular mostly infaunal deposit feeders
Ordivician - Recent
class holothurodiea
sea cucumbers
- usually grouped with echinoids (no arms, stem, or tail)
- genereally soft-bodied, skeelton reduced to isolate calcerous plates= ossicles
-calcerous rings encircles pharnyx or throat
-suspension feeders, deposit feeders
- all depths in oceans
Silurian to recent
abundant in Mazon Creek
class asteroidea
sea stars
- five arms
-internal body parts, water vascular system
- tube feet = ambulacral grooves
- highly mobile, use tube feet to move
- predators, can extrude stomach through their mouth killing and partially digesting their prey outside their body
ordovician - recent
class ophiuroidea
brittle stars, basket stars
- well defined central disk and separate arms
- scavengers, deposit feeders (basket stars filter feed on plankton)
ordovician = recent
class crinoidea
-cup like body carrying arms = calyx
-arms have ambulacra and tube feet
-may or may not have a stalk attaching to the substrate
-stalk made of separate pieces = columnals
ordovician - recent
major fossil groups - crinoids
3 subclasses of crinoids are known from Paleozoic
- differ in structure of arms and calyx
generally stalked
blastazoans
body covered by theca, made of interlocking plates with ambulacra (no arms)
- stalked filter feeders
- classes differ by arrangment of plates on theca
class blastoidea
blastoids
- highly standarized arrangement of plates
-complex internal folds of calcite below ambulacra
ordovician - permiean
class edrioasteroidea
sessile suspension feeders
often found growing on brachiopod shells
ambulacra grew in a curved, often spiral or nearly spiral pattern
subphylum homolozoa
fattened, bilateral, irregular
- elongate extension of the body - tails?
- rare
cambrian - devonian
echinoderm fossil record
first definite echinoderms appear in middle early cambrian
- all cambrian classes are low diversity, suspension feeders
- paleozoic - crinoids became dominant group, high tiering filter feeders
- gradual loss of other classes
- echinoderms have become dominant group
paleobiogeography
understand spatial patterns of diversity over a time
physical controls on organism distributions
seasons
prevailing surface winds
land and water
seasons
- summer = continent warmer than ocean, lower pressure in continent, winds flow in from oceans = bring moisture
- winter = continents cooler than ocean, higher pressure in continents, winds flow out from continents = cold, dry air flowing out towards coasts
- oceanic currents
currents from low lat. to high transfer heat from warm to cooler areas
biomes
physical factors strongly control organism distribution
- may lead to species with similar characteristics
“world’s major communities, classified according tot eh predominant vegetation and characterized by adaptations of organisms to that particular environment
ex. deserts, grasslands, reefs
evidence of past climates
- paleoclimates = datable earth materials that are climate-sensitive = proxies
coral reefs = tropical marine
glacial tills = cold and continental
evidence = floral assemblanges are climate sensitive - use pollen as proxies, oxygen isotypes; O16 & O18
(oxygen isotypes are preserved in carbonate shells
climate history
warm periods = green houses
cold periods = ice houses
- last 100 million years = warm climate at the end of mesozoic, climate cooling since oglicene
paelogeography
reconstruction of geography of a past time period
paleomagnetism = position of continents relative to ples-latitude and orientation
what did the continents look like in the past?
granites, volcanic rocks, metamorphic rocks, sedimentary facies and fossils, unformaties
paleoclimate models
computer models of past climates
permian - triassic = warm period 250 ma
period of abrupt warming 55 ma
last glacial maximum 21 ka
ecological biogeography
explanations of the distributions of organisms based on interactions between organism and their physical and biotic environments
provinces
regions over which communities maintain characteristic taxonomic composition
- separated by geographic barrier that blocks movement
can be defined on basis of endemism = endemic = confined to a single region or province, comsopolitan = multiple provinces, wide geographic range
provinces - faunal similarity
simpson coefficient = C/N X 100
c = number of taxa in common
n = total number of taxa in two samples
jaccard coefficiant C/(A+B -C)
C = number of taxa in common
A & B = number of taxa in samples a and b
wallace’s line
father of biogeography
many fish, bird, and mammal groups are abundantly represented on one side of Wallace’s line but poorly or not at all on the other side.
historical biogeography
reconstruct origin, dispersal, and extinction of taxa and biotas. The past distributions of organisms and how the evolutionary history of clades effects their present distribution
dispersal biogeography
distribution of organisms due to dispersal (moving away) from a point of origin. dispersal methods: - corridor - filter bridge - sweepstakes - "noah's ark"
great american interchange
north and south america united across isthmus of panama 3.5 ma
faunal exchange between provinces
porifera
multicellular animals - therefore metazoans
- different types of cells but not organized into tissues or organs
mostly marine, a few fresh water
virtually all sessile , epifaunal, filter feeders
porifera = “pore bearers” - bodies punctured by numerous pores
choanoglagellates
small single-celled protists
found in both fresh waters and the ocean
take their name from the circle of closely packed microvilli, or selnder fingerlike projections, that surrounds the signle flagellum by which choanoflagellates both move and take in food
- water moves into central chamber - the spongocoel (atrium) and water leaves via large opening - osculum
3 grades of organization sponges
ascon, sycon, leuconoid (skinny, medium, fat)
sponge skeletons
wide variety of skeletal materials
- calcareous plates
- organic collagen -like fibers = spongin (bath sponges)
- siliceous and calcareous spicules - needle like elements
- plates and spicules fossilize well, but most skeletons dissagregate at death
class calcarea
cambrian - recent skeleton composed of separate calcareous spicules - all 3 grades marine, usually shallow generally small
class demospongiae
cambrian - recent
90 to 95 percent sponge species
siliceous spicules, of spongin fibres, or both
leuconoid only, mostly marine, some freshwater
class hexactinellida
late precambrian - recent
glass sponges
sycanoid pattern
exclusively marine, usually deep ocean
stromotoporoid
extinct group of massive calcareous colonial marine organisms
important paleozoic and mesozoic reef builders
coralline sponges
leucoinoid sponges with siliceous spicules, calcareous spicules, or no spicules
may be polyphyletic
grow slowly - can be used as climate proxies
also fossil cahetetids related possibly
archeocyathids
calcareous sessile marine organisms lower middle cambrain very diverse in lower cambrian shallow water, usually carbonates reef builders tropical coned shape and double cupped!
receptaculitids
radically symmetrical carbonate skeleton
shallow water tropical environments - reefs
ordovician - permian
resemble sponges - probably superficial
cnidarians
wide variety body forms and complex life cycle
can be solitary or colonial
free living or sessile
soft bodied or calcareous
all possess nematocysts; stinging or sticking threads used to protect animal or capture prey
cnidarian morphology
bodies made of 2 layers of tissues
in between epidermis and gastrodermis is the mesoglea, a layer of jellylike substance which contains scattered cells and collagen fibers
2 general body forms; medusa and polyp
cnidarian life cycle
hydrozoa - alternate between a polyp and medusa stage
anthozoa - live only as polyp - true corals
cubozoa - hox jellies - toxic!
scyphozoa - medusa stage dominates - jellyfish
important fossil groups - cnidarians
precambrian - earliest found
coral like forms first appear in cambrian
3 main groups: class anthozoa, subclass zoeantharia, anemones and corals
scleractinian corals
body internally divided by partions - mesentaries
secrete skeepton aragonite = corallite
radial sheets of aragonite = septa, secreted between pairs of mesentaries
septa show 6 fold radial symmetry
solitary or colonial
become quite large
middle triassic - recent
rugose corals
horn corals skeletons of calcite important in ancient reefs both solitary and colonial bilateral pattern of septa ordivician to permean
tabulate corals
exclusively colonial
calcite skeleton
important reef builders
ordovician to permean
reef
composed of carbonates (limestone, dolomite)
carbonate buildup - a body of locally formed and laterally restricted carbonate sediment possessing topographic relief
bioherm - moundlike organic buildup
reef - buildup formed in part by a wave-resistant framework constructed by organisms - a wave resistant bioherm
distribution of modern reefs
less than 1 percent in area oceans
restricted temps
clear shallow water
low nutrients
controls on reef distributions
modern reefs are built by scleractinian corals = coral reefs
these corals have symbiotic algae in their tissue
coral feeding is fouled by sediment
easier to precipitate calcium carbonate in warmer water
reef geomtry
fringing reef - builds directly out from coast
barrier reef - separate from coast by a shallow lagoon
atoll - ringlike surrounds lagoon
modern reef organisms
3 basic classes
- frame builders
- binders
- debris producers
reef history
ordovician - beginning of true reefs - bioherms these reefs become large and widespread in the silurian and devonian
- global reef extinction end of devonian - no carboniferous reefs
permian - widespread reefs appear
triassic - first corals, few reefs
jurassic - diversity explosion
geological time
relative ages based upon order of formation
absolute ages - actual number of years since an event
