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
stratigraphy
study of layered character of edimentary and other stratified rocks, esepeically thier geomtric relations, compisitions, origins, and age relations
stratum
a tabular or sheet-like mass, or a single and distinct layer, or sedimentary material, visually seperable from other layers above and below…..
strata includes beds and laminae, bedding planes
principle of superposition
younger strata on top, older on bottom
principle of original horizontality
strata originally formed in horizontal sheets
principle of original lateral continuity
subsequent erosion dissects once-continuous layers
principle of cross-cutting relationships
younger features cut across older features
inclusions
a rock fragment within another
principle of inclusions
inclusion is older than the material enclosing it
unconformities
surface representing a large time gap in the local rock record.
disconformity - parallel strata above and below surface
due to interruption in sedimentation
nonconformity
metamorphic or igneous rocks overlain by sedimentary strata
angular conformity
tilted strata below unconformity - indicates, new sediments deposited on top, eroded back to surface
william smith
first surveyor constructing geo. map
realized - bodies of rock could be identified by distinctive groups of fossils
civier and lyell
cuvier showed that some animals have gone extinct and lyell showed that older rocks contained more extinct types than younger rocks
principle of fossil succession
species appear, exist for a time, and then go extinct
biostratigraphy
organizes strata into units based on their fossil content
biozone - fundamental unit
FAD
First appearance Datum - firs appearance in a local rock sequence
LAD
last appearance in a local rock sequence
concurrent range zone
overlap taxon range zone of 2 or more taxa
interval zone
interval betwen 2 successive FADS or two succesive LADS
index fossil
zone fossils - best fossils for correlation - used to establish zones cambrian - trilobites ordovician - silurian - conodonts devonian - brachipods mesozoic - ammonoids cenozoic - formanifera mollusks
evidence for common ancestory
- dna, genetic code is identical
- all organisms use ATP to carry energy
- all 20 amino acids that comprise living things exhibit “left hand chirality”
homeotic genes
suite of genes found in animals that:
- determine the axes of embryos then
- control how embryos are divided into segments, and indicate
- development of appropriate body parts in each segment.
micro vs macroevolution
micro = evo. at or level below of species macro = evo. above or at level of species
extrapolation
macro made up of micros
microevolution
- focuses on local pop., interbreeding groups vairiaton heredity overproduction selection chance
speciation
bridge between micro and macro
2 kinds of speciation:
1) anagensis - transofmration of one biological species into another
2) cladogenesis - splitting of one biological species to another
* in order for speciation to happen, must produce genetic isolation
mechanisms of speciation
allopatric speciation - pop of species become isolated due to crossing of or formation of a barrier - gene flow interruption
- isolated pop become genetically distinct
- if barrier disappears, pop remain genetically isolated
punctuated equilibrium
speciation is rapid relative to duration of species
- morph. change concerted during period of speciation
micro and macro redefined
micro - changes in gene pool species
macro - evolution of clades
macro evo phenomena
- origin of clades
- changes of diversity within clades
- extinction of clades
- changes in morphology
- extinction
domains of life
5 kingdoms: moniera, protista, fungi, plantae, animalia put into 2 divisions: - prokaryote - lack of nucleus - eukaryote 3 domains: bacteria, archaea, eukaryotes
archaea
extreme environments on planet
found everyone
hot springs, etc
bacteria
aerobic and anarobic bacteria
autotrophs - produce their own oxygen
cynobacteria - include photosynthesis and produce own oxygen
eterotrophs - fermenters and decomposers
protists
single celled eukaryotes
generally mobile
major fossil groups of protists
2 groups of rhizaria - formaniferida (forams) - radiolara (Rads) - predatory diatoms - photosynthetic related to brown algae
formanifera
have a shell (test) which may be agglutinated or consist of calcite, aragnote, or rarely silica. calcite is most common. - 1 to many chambers - wide variety of test form - benthic or palegic - large species have symbiotic algae - trap food on thin extensions of the cytoplasm called reticulopodia cambrian to recent - key part of marine food chain
radiolara
shells made of opaline silica, spherical or conical
- widely used for biostratigraphy and paleooceanography
- often show gradualistic evo. change
diatoms
unicellular algae with a cell wall impregnated with silica
- resembles a pill box
cretaceaous to recent
time scale
hadean eon - origin of earth 4.0 Ga
archaen eon - oldest rock - 2.5 Ga
hadeon eon
early formed crust was bombarded by meteorites
atmospheric components - hadeon eon
current atmosphere - nitrogen, oxygen, other
the earth system
comprised of physical components interacting with the biosphere
- lithosphere
- atmosphere
- hydrosphere
evidence of early life
- atmosphere formation
- lack of 02
-early life - organic compounds
stromatolites - large layered structions in domes and pillow where mats of cyanobacteria trap sediment - found in old crusty rock - fossil prokaryotes - difficult to distinguish from inorganic
- all evidence dating 3.5 old
proterozoic eon
protero = first zoic = life
2.5 Ga = 543 Ma
life and the atmosphere
photosynthesis changed earth’s atmosphere
- photosynthetic cynobacteria converted CO2 and H2O to organic matter and free oxygen
- oxygen accumulated in oceans - levels rose sharply about 2.4 Ga
- banded iron formations
- O2 buildup permitted diversification of life
- rising oxygen levels opened up the possibility of shallow water and land-dwelling biota - formation of ozone
proterozoic sediments
by about 2.3 Ga - first red beds contain hematite - abundant by 1.5 Ga
- carbonates also become common
- sedimentary rocks begin to look more common
origin of eukaryotes
organisms that contain nucleus
- respiration depends on oxygen - could not have evolved until sufficient oxygen present
- sexual repoduction
origin of eukaryotes
endosymbiosis - one bacteria engulfs another
acritarchs
spherical organic -walled microfossils
The ediacaran
last part of proterozoic
- 630-542 ma
- first evidence of mammals
- many questions - a failed experient in multicellular life that went extinct - quiet large
fossil embryos
570 ma, tiny fossils from china
- embryos in process of dividing
mistaken point - ediacaran
- abundant and diverse ediacaran fossils
- overlapping tuffs, deep marine slopes
- mistaken point fossils
cambrian radiation
3.5 to 1.7 Ga
543 ma - shells appear
- require a lot of energy to make and carry shella
- documentation of variety of mammals
2 cambrian sites where soft-bodied organisms preserved
1) china
2) british columbia - burgess shale
phanerozoic diversity history
anaylsis principally based on compilations of genus and family stratigraphic ranges
overall pattern of total diveristy shows:
- rapid increase in cambrian
- continuing increase through Ordicvian and reaches plateau until Paleozoic.
- low diversity early traissic
- diversity begins to continue to increase`
“The Big Picture” - Sepkoski
suggests 3 evolutionary faunas; groups of taxa that increase/decrease more or less in unison.
cambrian fauna: trilobites, inarticulate brachiopods
paleozoic fauna: articulate brachiopods, cephalopods, crinoids, tabulate & rugose corals, stenolaemate bryozoans
modern fauna: bivalves, gastropods, vertebtrates, echinoids, crustaceans, bryozoans
cambrian fauna
150+
trilobites
paleozoic fauna
400+ brachiopods horn corals crinoids bryozoa
modern fauna
450+ gastropods bivalves crabs bony fishes
dinosaurs - daipsids
most specios group of amniotes with about 14600 extant species including
lepidosaurs - snakes and lizards
ichthyosaurs
archosaurs - crocidiles
dinosaurs - includes birds
dinosaur diversity rapidly increasing in jurassic
first dinosaurs
eorapter
herrerasaurus
2 main dinosaur groups
ornithischia and saurischia
ornithischia
bird hips - bipedal plant eaters, pointy knobbly parts
saurischia
lizard-hips, huge, 4-legged plant eater
theropods
pipedal predatory dinosaurs
k-pg - extinction
65 million years ago dinosaurs, reptiles, marine invertebrate evidence: indium-enriched clay chicxulub crater
4 main groups of mammals
monotromeres
multituberculates
marsupials
placentals
highlights of mammal fossil record
- most mesozoic mammals are rodent size
- late jurassic - multitubruculates appear
- early cretaceous - marsupials and placentals
oldest tree dwelling animals
docodont
middle jurassic
oldest bat
eocene
non-echolocating bat
oldest whale
archaeocetes
- pakicetus, basilocauruss
hypsondonty and grasses
largeeeee teeth & C4 grasses
origin of humans
primates evolved in paleogene
apelike primates in miocene - 4.4 ma
homo - 2.4 ma
ardi
4.4 ma
walked upright but very flexible feet
origin of humans
homo eragaster 1.9 ma
neanderthals 2,000 to 30 ka
homo-sapiens 150 ka
Neanderthal DNA
mitochondrial differences
humans and nean. - 27.2 substitutions
more common with non-african
denisovans
40,000 years old
siberia
not related to Neanderthals at all
people of new guinea 3-5 percent similarity
causes of mass extinctions
late ordivician to devonian - glaciation
permo traissic - volcano
cretaceous - impact
human - sixth?
life during phiestocene
mammals included now extinct giants
beaver, sloth, etc
extinction facts
1 extinction happens every 20 min
200 to 300 years half of mammals will be gone
