Final exam Flashcards
What is Biogeography? (2 things)
The study of the geographic distribution of organisms and how they have gotten to be where they are today.
interpreting influence of evolutionary relationships
What is the latitudinal diversity gradient?
Basically: there are more animals near and around the equator, with population numbers dwindling around the poles. It is active, not static.
Who are some key people in biogeography? what did these mfs even do??? (CACA)
Charles Darwin: Evolution and Natural selection (duh)
Alfred Russel Wallace: Provided new info on faunal provinces and formalized many biogeographical ideas around today
Carolus Linnaeus: Classification method for species
Alfred Wegener: Plate tectonics and Continental drift
What was Sclater
- The first maps of biogeographic realms (biomes :D)
- Looked at the composition of fauna in a given biome and compared them.
Explain Wallace’s line (where/what it was, what types of animals)
- A boundary between SE Asia and Papua New Guinea & Australia
- marsupials and monotremes SE of the boundary
- Placental mammals NW of the boundary
What evidence supports such a drastic change in fauna in and around the Wallace boundary?
Water around Asian islands was shallower
Water between Asian islands and Australian islands was much deeper
Is Wallace’s boundary an example of sympatric or allopatric evolution?
Allopatric Evolution!
Wallace’s boundary is evidence of reproductive isolation between populations via a geographical barrier
Define Allopatric evolution and Sympatric evolution
Allopatric: ancestors split and evolve differently due to a geographic barrier (no gene exchange)
Sympatric: ancestors evolve into different groups without this barrier
what are the 3 types of allopatric speciation? (PVP)
Peripatric: isolated peripheral group
Vicariant: extrinsic barrier (think mountian)
Parapatric: large geographic area
What are some ecological factors affecting biogeographical influences on speciation? (6)
Moisture, temp, soil chemistry, light, food/nutrient availability, competition
what areas or (biomes) have high biodiversity and endemic species? (2)
mountains and islands
how could an ice age geographically affect a population? ie. why are they important? (4)
- Glacial expansion: sea-level drop
- terraforms the land: erosion and rivers
- changes composition of animals and plants (to those who are more adaptive)
- migration: gene pool mixing
what are the 3 main extinction hypotheses?
humans: overkill
climate: over-chill
Extraterrestrial impact: over-grill
what is some evidence for megafaunal extinction due to humans? (3) think wooly mammoths
- timing of extinctions = timing of human arrival
- some remains show signs of cutting or piercing from man-made weapons
- modern conditions would have likely happened in the past (causing irreparable damage): killing capacity, migration, disease
what is some evidence for climate induced “over-chill” extinciton? (3)
- stepwise and progressive drying as early as 700kya resulting in extreme climate variability
- small-bodied species were affected… bottom up ecosystems means megafauna are affected
- Africa experienced minimal glacial temp. changes, fits the continental scale pattern of low climate change (perfect refuge from impending ice!)
what is some evidence for extraterrestrial “over-grill” extinction? (4)
- carbon rich layer dating back 12.9kya lines up with abrupt onset of Younger Dryas (YD cooling)
- in-situ bones of megafauna occur below this black layer, but not in or above it (indicating vaporization?)
- Shocked quartz grains
- a shock wave, thermal pulse and event-related enviromental effects (biomass burning and food limits) led to this extinction
What is the ecological impact of megafauna in their habitat? (size, eating habits)
- once again.. size matters! these creatures would have been extremely important in determining the characteristics of their ecosystems
- the effects of grazing on vegetation by these beasts would be prominent: forest clearings/prevention of vegetation encroachment
How does evidence for over-killing hold up on a global scale?
not that great! while there is a strong case for it in Australia, the data is pretty scarce everywhere else. (like in NA we have evidence of hunting but no kill sites, yet ~70 extinct megafauna)
Define extinction (both local and global)
global: complete elimination of a species
local(extirpation): local elimination, can be reversed! sometimes a speices can be reintroduced
what is gamblers ruin? (bad luck)
- statistical concept stating that given a finite resources that go up and down with chance, you will eventually hit 0 (think gold in age of empires)
- relates to increase and decrease of population size (relative per species)
how many major and minor extinctions were there?
5 major: extremely high extinction rates
12 minor: higher extinction rates than normal, not always widespread
It seems like extinction events decrease in intensity through the phanerozoic, what could this mean? (3)
- living taxa are more resistant to extinction than ancient taxa
- earth might have become more stable for biota
- major perturbations may have become less common
what was the third largest extinction? what happened? what is to blame?
- ordovician-silurian: 2 peak dying times 100ks years apart
- killed 85% of sea life (most of life in general)
- caused by an ice sheet, causing a fall in sea level, changing ocean chemistry
what triggered the ordovician-silurian?
PLANTS! “Reverse greenhouse”: burial of organic matter –> cooling, glaciation, lower seas, no shallow habitat
when/what was the “age of fishes”
Devonian: great diversification of fish
- sharks, skates, rays
- jawed armored fish (placoderms; all dead)
- true bony fish (includes lobe-finned fish)
- eurypterid arthropods (predators)
- ammonoid cephalopods
what were some of the most advanced jawless fish?
Osteostracans: they had paired fins and complicated cranial anatomy (bony shields)
what was the largest of placoderms?
Dunkleosteus: giant placoderm
what were the terretrial environments in the silurian?
-vascular plants invade land, spore brearing plants
what were the terretrial environments in the devonian?
- rapid evolution of land plants (first trees, forests)
- earliest terrestrial arthropods (insects/scorpions)
- bivalve molluscs invade fresh water (moving “up the creek”)
- vast terrestrial lowlands (alluvial plains, wetlands, deltas)
what are lobe-finned fish?
- a clade of bony fish (living relatives include coelacanths and lungfish) think relicanth
- lungfish gave rise to tetrapods
what was the intermediate between lobe-finned fish and amphibians? (3 reasons)
Icthyostega
a) skull structure akin to lobe-finned fish
b) fish-like tail
c) four legs & hip/shoulder structures like amphibians
when was the invasion of land?
what happened?
DEVONIAN:
- devonian plants:
a) develop roots & seeds
b) create new habitat for animal invasion
c) first trees - First insects
- First amphibians
Why was the invasion of plants possible?
- Late Devonian glaciation on supercontinent
- sea level falls –> loss of marine habitats
- possible climate feedbacks: spread of forests, carbon burial, global cooling
What do Terrestrial Permian fossils tell us about how life was changing? (3)
- coal swamp floras replaced by seed-bearing conifers meaning DRIER LANDSCAPE
- amphibians replaced by radiation of reptiles (can reproduce away from water) MOVING INLAND
- evolution of THERAPSIDS (mammal like reptiles!)
a) legs beneath bodies
b) warm-blooded
what are the 3 types of fenestrae (and who do they belong to)?
Anapsid (no hole) - primitive reptiles
Diapsid (2 holes) - Dinosaurs, living reptiles
Synapsid (one hole) - Mammals & relatives (for jaw muscles)
what is the poster child for Permian REPTILES (and dino imposter)?
Dimetrodon
What are some characteristics of the end-permian (what died, who won)?
- 95% of marine species, ~50% of invertebrates
a) all: trilobites, rugose/tabulate corals, fusulinid forams
b) most: brachiopods, ammonites, lacy bryozoans, crinoids - ~70% of terrestrial vertebrate families
a) 75% amphibian
b) 80% reptiles
-fungal spore spike
What are some of the biggest changes resulting from the end-permian (Before/After, 4 topics)
Before:
- high diversity endemic life
- extensive reef communities
- coal
- 526 fossil animal families
After:
- low diversity cosmopolitan life
- no reef communities
- no coal
- 267 fossil animal families
what are 5 possible causes to the end permian?
- Global regression, draining of epicontinental seas
- loss of marine niches/ more competition
- less temperate climates (more extreme) - Drop in atmospheric Oxygen
- weathering & oxidation of organic matter
- reduction in global productivity - volcanism: from Siberian flood basalts and china
- lots of aerosols
- climate instability (fast cooling, overall warming) - Anoxia in deep ocean
- reduction of oceanic salinity due to deposition of evaporites
What is some evidence supporting volcanism relating to extinction events
Large igneous provinces (LIPs) and Silicic LIPs
- form at sites of mantle plume reuptions at hot spots
- not directly related to normal tectonic processes in upper crust
what was the oceanic refuge zone?
A zone sandwiched between lethally hot surface waters and poisonous anoxic deep water. It explains the types of fauna we see struggling through to the Triassic
What evidence supports oceanic anoxia? (2)
- Lack of burrowing traces in sediment (which returned after the extinction)
- Bivalves and gastropods are “micronized”
What are some notable features during recovery post PT extinction? (4)
- Coal gap lasting 10my
- Replacement of dominant flora by “weedy plants”, low diversity
- high diversity reefs are fully wiped
- stromatolites found in abundance –> lack of grazers
explain CAMP
(Central American Magmatic Province)
Extensive interval of volcanism, pushing extreme climate situation into a worse scenario. Areas of high oceanic productivity had pulses of anoxia and high concentrations of hydrogen sulphide. DURING TRIASSIC JURASSIC - LED TO EXTINCTION OF DINOS
What was to blame for the Triassic-Jurassic? (3)
Climate change, flood basalt eruptions and asteroid impact
What died during the Triassic-Jurassic? What survived?
died: marine reptiles, amphibians, reef-builders, molluscs, ~50% of all species died
lived: plants were relatively unaffected
What disruptive event is directly correlated to mass extinctions?
Flood basalts. 91% of flood basalts coincide with every mass extinction since the Permian
Describe the Signor-Lipps effect
- Fossil record is incomplete, so its unlikely that the first or last true individual of a species is a preserved fossil
- this blurs the timing of extinction even
- extinction is likely more abrupt than what is seen in the fossil record
How are background extinctions different from mass extinctions?
- A large geographic area protects against background extinctions
- “Extinction-Resistant” taxa go extinct just as likely as non-“Extinction-Resistant” ones during a mass extinction
What are 3 general mass extinction features
- Happens everywhere with similar intensity
- Tropical life experiences higher extinction rates
- land plants are resistant
Is the chance of extinction higher or lower for an older species compared to a newer species?
The odds to go extinct are the exact same.
What is a “normal extinction” for a speices? What is the average timeline?
- This defines the “life-span” of a given species in the fossil record
- usually about 5 million years
What are 3 abiotic mechanisms that control extinctions? (TMC)
tectonics
meteorites
climate
What falls under the grouping “Mollusca”?
Snails, slugs, mussels, oysters, clam, squids, octopuses
What morphological features are indicative of mollusks?
calcareous exoskeleton, foot, viscera, mantle cavity, mantle, shell.
Why are mollusks diverse?
Hard exoskeleton, yet moving.. so unanchored. Mobility allows for choice of habitat
What can be interpreted from a mollusks shell? (3)
- record of the animals growth (as they don’t molt)
- record of environmental conditions of the time
- oxygen isotope ratios, pollutants, “shell rings”, environmental conditions
Outline a basic mollusk (symmetry, sensory organs, morphology)
- Bilaterally symmetrical
- head has eyes
- mouth has teeth (radula)
- foot used for crawling/ burrowing
- mantle which secrete calcareous shell
- shell made of aragonite
What is the supposed ancestor of mollusks? briefly describe it
Aplacophora: shell-less, deep water, Cambrian?-recent, 2 main groups, possess a radula
What are polyplacophorans
- 7-17 plates
- Ediacaran-recent
- marine, global habitat
What is the KNOWN first mollusk? describe it
Monoplacophora: Cambrian-Recent, Deep ocean, soft/hard substrates
Broadly describe Gastropoda
- Cambrian - Recent
- most use a radula for eating
- tend to have a big foot, heavy tortion, and tentacles
Briefly describe Bivalvia:
- Shell has 2 valves
- Cambrian-Recent
- Aquatic, but marine-fresh
- foot open and closes the shell
- not all are symmetrical
What are rudists?
- Reef formers ~100mya
- Went extinct 65mya
- replaced by corals
What are some key morphological features of echinoderms? (3)
- 5-fold or bilaterally symmetric
- Water vascular system
- spiny skin made of high Mg Calcite
which taxonomic groups belong to echinodermata? (5)
think B.E.A.C.H
Blastozoa, Echinoidea, Asteroidea, Crinoidea, Holothuroidea
What group has tube feet?
How are they used/controlled?
Echinoderms! used for movement and feeding, controlled by the water vascular system. Areas with tube feet are called ambulacral areas.
How is pressure controlled in the echinoderm body?
a valve called the madreporite
What is the benefit of an echinoid having a flat test?
a flatter test allows for unidirectional movement and burrowing
what part of the crinoid is best preserved in the fossil record?
Crinoid ossicles (CaCO3 skeletons)
Are Echinoderms deuterosomes or protosomes?
Echinoderms are deuterosomes
do all foraminifers reproduce the same way/in the same place?
no, there are 2 types!
warm water species reproduce near the surface where growth is optimum
cold water species tend to reproduce further down for optimum growth
what is the use for microfossils? (3) PBP
- biostratigraphy
- paleoceanography
- pollution monitoring
What is CLIMAP and what did it do?
Climate Long range Investigation mapping and prediction:
- quantified cooling since the last ice age
- proved Milankovitch cycles control glacial cycles
How are benthic foraminifera used to measure pollution?
They grow deformed (big time) when exposed to heavy metals like zinc, copper etc.
which fossils are used for the paleozoic?
brachiopods, trilobites, chitinozoans, conodonts, graptolites
which fossils are used for the mesozoic?
foraminifera, ammonites, pollen
which fossils are used for the cenozoic?
foraminifera, diatoms, pollen
What is the range of Θ for normal polarity in magnetostratigraphy? What is it for reversed?
normal polarity: -90°-0°
Reversed polarity: 0°-90°
what is magnetostratigraphy used for?
- stratigraphic dating sequencing
- paleogeographic & plate tectonic reconstruction
- correlation
how are verterbrate fossils found?
a) permineralized bones
b) occasional soft tissue preservation
i) carbon film
ii) skin impressions
iii) amber
what characteristics define a dinosaur?
- Diapsids: 2 temporal fenestrae
- Archosaur: teeth in sockets, anorbitlal fenestrae, large 4th trochanter
- Upright posture (not sprawled)
briefly outline ornithopoda
- herbivores
- bipedal
- large beaks
- complext chewing technique
briefly outline marginocephalia
-bony hard hat head
briefly outline sauropodomorpha
long neck lookin ass
briefly outline theropoda
- carnivores
- blade teeth
- bipedal
- early therapods occurred in the Triassic and early Jurassic
briefly outline Ceratosauria
- Large carnivores
- horned skull
- tiny arms haha
briefly outline Coelurosauria
- carnivores and herbivores
- tibia longer than femur
- feathers
Briefly describe maniraptora
- semi lunate carpel with 3-fingered hand
- retroverted pubis
briefly describe paraves
- wings
- powered flight
- sickle-clawed
briefly outline Avialae
- more closely related to birds
- includes the first bird “archaeopteryx”
which taxa fall under “crown-group birds”?
Enantiornithes
Ornithurae
Aves (Ostrich and turkey)
briefly describe the K-Pg extinction
- one of the big 5
- extinction of ammonites, non avian birds
- meteor impact causing global firestorm
- bedding with iridium
why did aves survive the K-Pg?
likely due to their size and diet-type. having beaks really helped them out compared to long-mouthed dinos
