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Flashcards by ameliabmargrave, updated more than 1 year ago
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Created by ameliabmargrave
over 8 years ago
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| Question | Answer |
| what are darwins 4 postulates? | 1. There is individual variation within a species 2. More offspring produced than will survive to breed 3. Survival & reproduction of individuals is not random- survival of the fittest 4. Some phenotypic traits are heritable |
| what evidence is there for evolution? | The Fossil Record Biogeography Comparative Anatomy Comparative Embryology Molecular Genetics |
| radiation of mammals occurred when? | 65 mya after dinosaur extinciton |
| biogeographical evidence for evolution is? | how species are related - through a geographical view: Island species - the island furthest away is least related to the mainland. papua new guinea and australia wallace's line -position of continents millions of ya. |
| what is comparative anatomy and how does it link evolution? | comparing how similar morphological structures are in different species i.e. hand of human and wing of bird are same bones, but adapted and modified - descent with modification from common ancestor. - vestigal organs |
| what is convergence? | It is not homologous - but convergent evolution where both species have separately evolved this characteristic because it benefits them in their environment. |
| comparative embryology | using examination of homologous features found in embryos that are not apparent in adults. humans, dogs and chickens, etc., all have gill pouches - these just turn into lower jaw, thyroid, etc. |
| molecular evidence | Phenotype and genotype - however this is impacted by the environment |
| what is heritability and its range? | the passage of genetic information from the adult to its offspring - Heritability = 0 all variation is due to environment - Heritability = 1 all variation is determined by genotype |
| what is macro evolution? | above the species level |
| what is micro evolution | within a species or population |
| what is gene flow | Movement of genes between populations |
| what is genetic drift? | variation in frequency of different traits occurring in a population when some are randomly killed (stepping on beetles example) |
| in what age were the origins of multicellular animals? | Pre cambrian 600mya |
| what time did prokaryotes appear? | 3500mya (stromatolites) |
| what time did eukaryotes appear? | 2100-1004 mya |
| how old are the burgess shale? | 520mya (middle cambrian) |
| what is the first chordate ancestor? | Pikaia gracilens, found in the burgess shale |
| Urochordata | tunicata |
| cephalochordata | amphioxus |
| myxiniformes | hagfish |
| petromyzontiformes | lamprey (brook/river lamprey) |
| gnathostomes | Jawed fish |
| ray finned fish | actinopterygians |
| lobe finned fishes | sarcopterygians 8 spp. coelacanth, lungfish |
| cartilaginous fish | chondricthyans |
| name 3 functions jaws benefit | 1. active predation (capture and bite) 2. manipulate food (improve digestion) 3. herbivory (grazing possible) 4. mating (nest building, grasp mate, mouth brooding) 5. improved forced gill ventilation |
| placoderms (such as?) have what adaptations? | =dunkleosteus, could move due to joint. armoured fish -pectoral and pelvic fins -jaws -no teeth -head trunk joint -benthic species |
| how do shark teeth develop, compared to ours? | from the skin rather than the bone like ours |
| jaws developed during which orders? | chondricthyans and sarcopterygians |
| what order are chimeras and ratfish? what class are they? | Holocephalii chondrichthyans |
| what order are sharks, skates and rays under? in what class/super order? | elasmobranchii chondrichthyans |
| what do shark jaws do to benefit catch success? | they are hyostylic jaws; they open, then push up and outwards extending their reach. |
| latin for Ray finned fish? | Actinopterygii/gians teleosts most diverse group under this 26 000 spp. |
| Teleosts started what? | to radiate in the cretaceous period and are now 96% of all fish. changed the body plan |
| what are the two main groups in teleosts? | Ostariophysi acanthopterygii |
| what teleost developed ram feeding and how does it work? | herring, mackerel the premaxilla and maxilla open with a fold of skin stretched between whilst the fish constantly swims forward, forcing water in. |
| what other teleost developed suction feeding? | (evolved independently in several lineages) jaw bones and premaxilla stretch out and up flap forwards to suck in a rush of water. |
| moray eel has what adaptation? | teeth in throat! come forward as the eel opens its mouth. |
| a) Squalus b) Latimeria c) Neoceratodus d) Teleost | |
| What problems are created by an aquatic existence? | -Movement –Bouyancy –Osmoregulation –Gas exchange –Senses –Temperature –Pressure |
| what direction do these factors move the fish? -bouyancy -weight -thrust -drag | = upwards = downwards = forwards =into fish (backwards against fish) |
| oscillation =? | side to side motion |
| what is a myotome? What are these separated by? functions? | a segment of muscle (orange parts of salmon) and they are separated by myosepta (white lines). Myosepta stop muscles pulling against each other. |
| what shape muscle creates what kind of movement? | |
| what function do myotomes have? | To lie next flexible vertebral column focus contractile force onto column away from other muscle blocks, this allows the skin to flick back the energy when pulled. |
| fast twitch muscle provides....? slow twitch muscle provides....? | ...a fast, short burst of movement. Meaning large amount can be set aside for use less often. (white coloured) ...a constant swimming speed, cruising, migration, long distance, that does not become fatigued quickly. (red coloured) |
| Water causes what effect on thermoregulation? | It has a high heat capacity, so draws out warmth from fish faster. |
| Retia mirabilia arteries and veins. These exchange the heat from muscles mix with the cold blood coming from the gills to reduce heat loss, through counter current system. - this allows further range and faster speed when bursts of speed required. | |
| what type of movement do these fish use? Eels? Tuna? Box fish? Rays? Bowfin? Cod? Triggerfish? Wrasse? | Anguilliforme Carangiforme Ostraciiform Rajiform Amiiform Subcarangiform Balistiform Labriform |
| where is drag most potent? | Pressure - pressure at the nose, higher than at tail to vorticity skin friction - viscosity of water makes it stick to surfaces |
| what reduces drag? | - streamlining. - reducing surface area of fins - i.e., using finlets, cutaway tail, foldaway and collapsible fins, turbulence at water boundary (shark scales disrupt water produce turbulence), mucus. - behaviour (flying fish, environment lifestyle). |
| Lift prevents the fish from sinking, what are the two main types + how do they work? | Dynamic: Airplane wing shape, to exert downwards force on air which pushes up on "wings" (shark) -must keep swimming, not hover, or swim backwards. Static: seawater = 1027g fish almost x3. gas/swim bladder = 5-7% of body. oil. |
| What is the gas bladder structure and and how does it work? | v |
| what are the 2 swim bladder types? | Phyostome outpocket of digestive tract. adult retains pneumatic duct. Phyosoclist - young may have open duct, adults closed, with secreting gas gland and re-sorption gland. Needs mechanism to fill air from its own body (gas gland) |
| how does a physostomatous fish fill and empty its air bladder? how does physoclistus? | =by gulping air at the surface =by burping to release air (generally more primitive sp) some use gas from oxygen in water passed via blood (more advanced sp) |
| this image shows....? which is what iknd of lift? | The production of gas through: gas gland produces lactic ACID and CO2 lowered pH causes hemoglobin to lose oxygen countercurrent system raises partial pressure of gases =static lift. |
| what other function does the swim bladder have? | can produce sound - many fish do! also use guanine crystals to stop gas getting out |
| what is squalene? | oil (lipids) found in shark liver - remember catshark practical. Less dense than water, so helps float. some fish put this in muscles. |
| what are the 4 key forces fish must content with? | bouyancy weight thrust drag |
| name mechanisms to generate lift? | -gas bladder 2 different types? -constant swimming -oil |
| what function does the gill arch have? | the gill arch can be used to crush prey, using bony plates. |
| what is a special feature of lungfish? and what type of swim bladder does it use? | they use their swim bladder as a lung, so can be out of water, propping themselves up on fins. Physostome |
| There is a lower concentration of oxygen in water compared to air. What happens to oxygen as the temperature of water: increases? decreases? | it lowers it increases |
| what is the latin for an Antarctic icefish? In waters of -2 to 4 degree's C, how does it survive? | Notothenioidei Uses Unidirectional flow (mouth->gills->exit) to reduce energy cost. (buccal pumping) reduces bone density and has lipid storage for buoyancy no haemoglobin |
| how does buccal pumping work? | Inspiration: 1.Buccalcavity expands, pressure drops 2.Water enters mouth down pressure gradient 3.Opercularcavity expands, pressure drops 4.Mouth closes, pressure in buccalcavity higher than opercularcavity 5.Water enters opercularcavity Expiration: 1.Operculum contracts, pressure in cavity higher than outside 2.Buccalcavity contracts, pressure rises 3.Water forced out |
| what is another method of ventilation (sometimes obligate)? | ram ventilation - the fish must constantly swim to receive oxygen. -mackerel, tuna, sharks. more efficient energy use than buccal pumping. also reduces drag. |
| what system is altered in order to cope with ram ventilation and how? | circulatory, as the blood must flow in the opposite direction to the incoming water. (oxygen would level out if same direction, so reversed allows maintained pressure diffusion). |
| How does the circulatory and respiratory system of fish larvae function? | So small and in high level environment, gas exchange can occur across body surface, and so little need for gills present and no haemoglobin is required. |
| gill arches - average number? which arch supports the mandibles formed by the "?" arch? | 5 in most fish 6-7 in gilled sharks (basking shark) the hyoid (2nd) arch supports the mandible and maxilla formed from the palatoquadrate (upper) and mandible (lower) from the 1st gill arch. |
| how did this change the development in humans? | Gill arches derive from pharyngeal arches and in human embryo's form the the jaw, parathyroid.... |
| showing the gill arch and how it has evolved to be used in human system. | |
| why does the laryngeal nerve have to travel to the heart and back to the face? | during evolution it got trapped on the wrong side and so must loop under the heart to travel back up |
| how do the gill rakers work? Explain in 3 steps | 1. vortex at the top of the mouth is created by the rakers. 2. Food particles accumulate, get stuck to mucus lining the mouth 3. mucus forms into bolus and is swallowed. |
| what are the two different methods? | Hydrosol (dead end) - the food gets stuck between gill rakers. crossflow - the food is passed along as the water is drawn through the gaps between the gill rakers. |
| how do marine fish cope with osmoregulation? | the ionic concentration in the blood is lower than the surrounding water and so they must constantly drink to replace lost water. |
| how do they cope with the high salt levels? | chloride cells in the gills, rich in mitochondria, help the process of ATP -> ADP by using the sodium to produce potassium and change the pH. Uses the transporter proteins. |
| where else does osmoregulation occur? | in the kidney |
| how do freshwater fish osmoregulate? | by using the sodium/potassium pumps, just the other way round. I.e., in Teleosts, Large ionic concentration in blood (> surrounding water). produce large amount of dilute urine (salts in kidney) gills take up salts. Chondrichthyes: blood has high Urea, Urea + ions = osmolarity similar to seawater. kidney + rectal gland and gills conserve urea. |
| so if for example a flounder (paralichthys lethostigma) loses: 8% of body weight from osmosis of fluids -0.4% of body weight through urine 2.7% through feces how does it regain lost osmotic components? | by drinking 11% of body weight each day -Absorbs around 76% of the water… …but 99% of the Na+and 96% of the Cl- •Between 8-17% of resting metabolic rate is dedicated to pumping ions |
| in what order does evolution workfor physiological processes? | Evolution locomotion respiration feeding Environment |
| why is the operculum important? list 3 reasons. | 1. protects the delicate gills. 2. used in buccal pumping to create pressure. 3. important for later modifications in tetrapods. |
| what roles do gills have? what does gas exchange depend on? | gas exchange, feeding, osmoregulation unidirectional flow of water and countercurrent exchange mechanism |
| what lineage do vertebrates come from? | sarcopterygians |
| what new technologies allowed further investigation and new discoveries in fossils? | CT scans of bones in rock 3D reconstructions --> functional analysis |
| what species did fish tetrapod transition start with? | Eusthenopteron (had pectoral fins plus post anal fins) |
| the second transition species was...? | at around 385mya Panderichthys (lengthened muscle to fins) |
| the third? | Tiktaalik bones beginning to look hand limb like on pectoral fins. skull shape crocodile like. |
| fourth? | Acanthostega (365mya) very long tail full fore and hind limbs. |
| and finally the 5th? | Ichthyostega (362mya) |
| why would fish benefit from evolving limbs for use underwater? | land plants increased the nutrient flow into the sea. increased microbial activity - decreases oxygen. - so benefit by popping head above surface. |
| what other factor occurred at the same time as limb development? | a drop in oxygen levels, calling for a need to move out water to get oxygen in higher quantities. |
| what advantages did the early lolobe-finned fish Eusthenopteron have that helped the evolution to limbs? | pectoral girdle stronger solid skeleton to support - however, it couldn't crawl on land. |
| around what time was Acanthostega present, with what adaptations? | 365 mya - the what period...? bones supporting the gills limb skeleton |
| what did ichthyostega have to benefit the transition onto land. | had four limbs, however hind only moved up and down (dorso-ventral) used as paddles, fore limbs similar to mudskipper. Fully aquatic. - retained gills. breathe air in shallow water using lungs. vertebral column not lateral, orientated dorso-ventrally. |
| when were the first tetrapod tracks on land found to be dating to? | 395 mya. |
| what could have happened to the ichthyosteglians? | a lineage of tetrapods moving in a modern directions/fashion may have predated them by 20 my |
| what is the name of the gap showing a gap of tetrapods being present for ...how many years? what happened in the end? | Romer's gap (began ca., 335 mya in devonian period ~20 million years succeeded by more modern groups in Carboniferous |
| how many species went extinct in the late devonian extinction? what did mass extinctions allow? | 70-80% of species they opened up new niches and allowed new radiations of previously unknown groups to evolve in new niches. |
| what did the late devonian extinct allow? | paved way for diversification of other basal groups, including amniotes |
| when did pentadactyly evolve? | after the late devonian extinction. (reduced to 5 digits ;) |
| what happened after the devonian extinction that benefited being on land? | insects diversified (Carboniferous), providing ample high protein food source for terrestrial predators |
| define an amniote (developed in the carboniferous period) | an animal whose embryo develops in an amnion and chorion and has an allantois; a mammal, bird, or reptile (the three layers of the "embryonic egg" |
| which species was it that evolved pentadactyl foot? | Perderpes also lateral foot extension able to loco-mote terrestrially. |
| there was also a return to what kind of lifestyle? (in start of carboniferous) | return to aquatic lifestyle sp such as: Crassigyrinus Eogyrinus |
| what time did all the amniote (and most tetrapod)lineages become extinct? what was this extinction called? | 240 mya - end of the permian period The Great Dying. (Permian-triassic) most severe event in earth |
| how many marine (?) and how many terrestrial vertebrates went extinct? what was the supposed cause | 96% marine 70% volcanism trapping |
| what were the Aistopoda, and what did they help evolve? | They are limbless, snake-like kinetic skull, aquatic and also possibly terrestrial - they still need water to reproduce. |
| what did temnospondyli look like? | Newt-like (but large, <4-5m) to alligator, one in brazil reaching 9m. |
| which tetrapod is not an amniote? | amphibians |
| when did first amniotes appear? what did this allow? | early carboniferous, 20-30 million years after first tetrapods! Removes the need to reproduce in water! first were small lizard like creatures |
| amniote evolution led to...? | viviparity! |
| what were the permian-only aquatic amniotes? the earliest amniotes weren't viviparous, what did they have? | mesosauria probably a leathery shell (poor fossilisation) |
| what is an innovation of being an amniote? | Costal ventilation (where muscles inflate lungs!) -Reduced need for cutaneous gas exchange – more waterproof skin -More varied head shape Buccal pump requires broad, flat head Constrains jaw muscle evolution Constrains foraging mode? -Allows longer neck Different foraging modes More complex brachial plexus more complex forelimb innervation |
| this new head and jaw adaptation allowed what to evolve? | herbivory! Woo Veggie! in the permian. -wide diversity: synapsids - most improtant in permian, as led to mammal-like reptiles and mammals after diverging in carboniferous. sauropsids - led to diapsids (led to birds?) |
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