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Biology Test One 2


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What is Perfection of Sponges?
study by the Joseph Bidder in 1944 reveals what E. G. Leigh later called "the perfection of sponges."
Sponges in still water should maximize distince.
Maximizes water to be cleaned of waste products, and reacquires food particles
Symmetry of Porifera?
Used water exit in Porfiera?
Momentum is equal to what?
Velocity times Mass
Specialized cells to paralyze prey
Characteristics of Cnidarias?
Two cell layers, blind guts
Radial symmetry
Cnidarian Life cycle?
Polyp (sessile) (reproduce asexually)
Medulas (floating)(sexually) (eggs turn into free-swimming planula larva)
Four types of polyps in Portuguese man-of-war
a pneumatophore, or float;
dactylozooids, or tentacles;
gastrozooids, or feeding zooids;
gonozooids which produce gametes for reproduction
Symbionts that contain photosynthetic algae in corals.
This is why corals live in nutrient poor environments and stuck to surface waters
Comb jellies, locomotor organ that consists of eight comb-like rows of fused plates of cilia called ctenes.
Ventral nervous system
Free floating larva collect food with compound cilia
Dorsal nervous system
Groups of protostome invertebrets
What is the lophophore?
Specialized feeding organ (occurs in 4 of major groups known as Lophophorates)
What is symmetry of flatworms?
Bilateraly symmetric, dorso-ventrally flattened
What is acoelomate?
Animal lacking coelom
Body cavity made from splitting mesoderm into two layers
Only have a mouth
Pseudocoel functions as a hydrostatic skeleton
CIliated structure on head called corona, doubles as locomotion and feeding organ
Body divided into 3 parts (Prosome, mesosome, metasome.)
Phoronid worms, Bryozoans, Brachiopods
Phoronid worms?
Sedentary worms that live in chitnous tubes in sand or mud attached to rocky substrates
Sexual reproduces by releasing sperm in water, collected by other individuals
Colonies grow asexually
Two halves are dorsoventral, rather than left-right
Brachiopods do not extrude lophophore into enviroment
Phylas of Spiralians?
Nemertina, Anelida, Mollusca
Ribbon worms, contain a special cavity, called the rhynchocoel wherein floats an extrusible proboscis which is the feeding organ.
Metameric body plan (duplication of internal organs)
Main groups of Annelids?
Polychaetes, Oligochaetes (earthworms), Leeches, Vestimentiferans
Live in deep ocean sediments near hydrothermal vents. Vent species contain endosymbiotic projaryotes-fix carbon via oxidation of H2S
3 Parts of Mollusc body plan?
Foot, mantle, Visceral Mass
Mollusc foot?
Foot used for locomotion modified into borrowing organ in clams, and arms and tentacles in cephalopods
Layer of cells that secete articular membranes. These consist of plates
Growth stage between molts
Five groups of Ecdysozoa
Priapulida, Kinorhyncha, Chaetognatha, Nematomorpha, Nemtoda
Cucumber shaped worm
Small detritus feeders manifesting segmentation
Arrow worms, tripartite body plan (head, trunk, tail)
Horsehair worms
Arthropod-like groups
Onycophora, Tardigrada
SLug like, characteristic of humid environments.
Existing in immense densities. Lack circulatory and respirator systems
Basic structure of arthopod evolution
Reduction, fusion, specialization of segments
What are the groups of arthropods?
Trilobites, Chelicerates, Crustacea, Uniramians
What are Trilobites, and their body plan?
Bottom dwellers, tri-partite body plan-cephalon, thorax, pygidium
Cephalon of trilobite?
Formed by fusion of the first four segments, heavily armoured with prominent compound eyes.
What are Chelicerates and body division?
Divided in two parts, Anterior cephalothorx, and posterior abdomen
What is the appendage of Chelicerates called Chelicera?
The first pair of appendages modified into feeding structures
What is the appendage of pedipalps?
Second pair of appendages often specialized into claws for grasping prey
What is the most advanced Chelicerate?
Spides.... Progressive features such as web construction, complex behavioral patterns, social organization
Appendages are two parts. Common for crustacea
Appendages are three parts. Insects
Characteristics of Crustacea?
Cuticle highly calcified, Head has 5 pairs of appendages, 2 are antenna like, pair of mandibles, two pairs of accessory feeding appendages (first and second maxillae)
Fold of protective exoskeleton over head and other segments
Free-swimming planktonic larva used for reproduction of crustacea
Social hymenoptera?
Ants, wasps, bees, where one observes complex societies with individuals specialized behaviorally and morphologiclaly for different tasks
Segmented body plan that is lost in adults of arthropods, but present in embryonic stage of all
Groups of deuterostomes?
Chordates and Echinodermata
Echinodermata characteristics?
Internal skeletons, Water vascular system (calcified hydraulic canals)
Function of tube feet in Echinodermata?
Gas exchange, locomotion, feeding
What is the symmtry of the echinoderm?
Larvae are bilaterally symmetric, adults are pentameral symmetry (SECONDARY feature)
Paired appendages first appear in what?
Appeared as fins in jawed fish (gnathostomes)
In line of fish leading to tetrapods, fins become limbs
Explain the evolution of gills
First used as filter feeding mechanism. Water entered through mouth and water exited gill slits

Gills then functioned as respiratory organs
When did jaws form?
Starts with fish belonging to class Placodermi, first two pairs of gill arches are lost and third modifies to jaws
Explain how gills are used as respiratory organs
Deoxygenated blood is pumped anteriorly by the ventrally situated heart, and then over the gills through aortic arches

Reoxygenated blood flows poseteriorly through the dorsal aorta.
Cartilaginous Gill arches support gills and blood vessels
Explain the embryology of the ear ossicles
Two of the middle ear bones begin as jaw bond, and then migrate to new positions
What is the Ontogenetic Law?
Modern day version of Haeckel... Mutations which modify development are less likely to be lethal if their action occurs later, rather than earlier, in development
What is a living example of a Cephalochordate?
What are the theories of chordate evolution?
Neotonic theory, and Amphiouxus one
Neotic Theory of Chordate origin?
States that larvae became sexually competent (NEOTONY), and as a result sessile adult phase is lost
What is an important theme of chordate/early vertebrate evolution?
Progressive integration of the visceral and somatic parts of the body.
Parts derived from gill basket and larval tail
Amphiouxus theory?
Amphioxus like chordates arose from the neotonic larvae of sessile unrochordates such as living tunicates.
From where did tetrapods evolve from?
Descended from lobe-finned fishes, Evidenced by dental and skeletal characters
What are the principal evolution ary steps for fish?
First first lacked jaws, Modern fish divided into Chondrichthyes, and Osteichthyes, and Jaws first appeal
Class of fish that lacked jaws. Fossils mostly belong to group Ostracoderms, and living species Cyclostomes
Two groups of modern fish?
Chondrichthyes, and Osteichthyes
What are Chondrichthyes?
Carilaginous fishes (sharks and rays)
What are Osteichthyes?
Bony fishes
In what group did jaws first appear?
Placoderms. Some had paired fins, and included parrot-beaked ARTHRODIRES
What is the basic split among bony fish?
Actinopterygians (RAY-finned), and Sarcopterygians (LOBE-finned)
What is included in Actinopterygians?
CHondrosteams (sturgeons, paddlefish, birchir and extinct paleoniscoids)
Holosteans (gar pike and bowfin)
and Teleosts (most contemporary freshwater and marine fishes)
What is included in Sarcopterygians?
Crossopterygians (RHIPIDISTIANS, ancestors of all tetrapods), Coelacanths, African and Australian lungfish
What is the evolution of Actinopterygians?
Evolved in freshwater, re-invaded marine environemnts in Mesozoic.
What does the bladder functions as in the sturgeon?
Functions as a buoyancy organ which animal gulps and discharges air
What is a swim bladder?
Specialized areas that secrete or resorb gas in most living bony fish
Which came first? Lungs or swim bladders?
Swim bladders evolved from lungs
What did amphibians evolve into?
Primitive reptiles which evolved contemporary reptiles , archosaurs (dinosaurs and birds) and mammals
Explain the importance of the developement of the egg?
The evolution of the amniotic egg allowed early reptiles from reproducing in water. Egg is a portable pond.
What are the four extraembryonic membranes in an egg
Yolk sac (holds food), Amnion (surrounds embryo with bag of waters), Chorion, and Allantois (serves as respository for dissolved emryonic wastes)
The chorioallantoic membrane in the egg is formed from what and what is its purpose?
CHorion and allantois form it. Serves as an embryonic lung, by allowing gas exchange (CO2 and O2) through porous shell.
What are the 3 major challenges to the organ systems?
Gas exchange, circulation and salt and water balance?
What are the tasks required with gas exchange and circulation?
Get O2 in animal, CO2 out. Transport gasses in and out of tissues, and Regulate breathing (supply), overall metabolism (demand), and production of cells
Explain Fick's Law of Diffusion?
All adaptiations that maximize respiratory gas exchange influence one or more compounds of equation Q=DA((P1-P2)/L), Q is rate O2 diffuses between two locations, D is diffusion coefficient, A is cross-sectional area, P1 and P2 are partial pressures, L is path length
How do animals maximize Fick's Law?
Maximize D for respiratory gases by using air rather than water. Other adaptations for maximizing this must influence the surface area and partial pressure
Why is Blood flow countercurrent to the flow of water over the lamallae?
This maximizes the diffusion of oxygen into the blood. In countercurrent exchange the water is always more saturated than the blood so that the gradient of O2 saturation exists over the full length of the exchange surface
What are "Hot" fish?
These fish keep their swimming muscles warm by placing blood vessels in close proximity to veins. Heat retains. Bees and wading birds have same type of thing.
What are the two basic breathing schemes that are present in birds?
Two breating cycles and Air sacs that extend into long bones
What is the two breathing cycles of birds?
Inhalation-exhalation moves the air into the airway and to the posterior airsacs, then to lungs, then to anterior air sacs, then finally out of bird.
What is tidal breathing?
Air flows into lungs, and then out.
Why is the avian breathing a superior system?
Allows a higher sustained rate of metabolism for longer periods, Can survive at high altitudes where the partial pressure of oxygen is insufficient to keep a mammal alive
Who have hollow bones besides birds?
Dinosaurs and their thecodont ancestors
What is biology the study of?
Living system's form, function and developmental and evolutionary origin
The femur is a BLANK structure
Load bearing
How the trabeculae arranged in the femur?
They are arranged along lines of compression and tension (they intersect perpendicularly)
What is a functional or adaptive explanation?
It explains what the structure is good for
What are some skeletal elements that have design straegies in term to loading?
Skulls and horn cores of giraffes and sheeps and goats.
What is the purpose of having stress bearing skeletal elements?
Protects against stress resulting from contests (clashing and butting with the head and horns) for social status and matting, and the fact the to eat the animal must crush calcareous shells
What is an developmental explanation example?
Distribution of trabeculae happens in response to applying force
What is an evolutionary explanation example?
In reference to femur this would focus on long-term changes in the developmental systems that control osteogenesis
Who proposed the theory of evolution and when?
Charles Darwin and Alfred Russel Wallace in 1858
What is uniformitarianism and who came up with it?
In Charles Lyell's Principles of Geology he aruged that geological change was the accumulated consequence of continuing processes: vulcanism, erosion, sedimentation,
Which places did Darwin observe while on the Beagle?
South America and the Galapagos Islands
What is excess biotic potential?
Organisms plan to produce more offspring than can survive to become adults
What is an example of excess biotic potential (in reference to bacteria)
In course of a week, a population of bacteria would grow to ball the size of earth, exponential population, but long before this forces would intervene... They would run out of resources or foul environment,other organisms would move in and eat them
What is role of bacterial mats in the evolution of Earth?
Played key role in oxygenating the atmosphere, now contemporary bacterial mats live in environments inimical to predators
What is the Principle of Malthus?
Unfettered growth would sooner or later cause a population to run into wall of limiting factors?
What is the Principle of Malthus named after?
English Pamphleteer who argued that excess population in human species inevitably leads to death by famine war and pestilence?
What is the implication of variation within a species?
Some of this variation affects probabilities of reproduction and survival--determines which offspring survive and reproduce, and some of this variation is heritable
Given sufficient time, what do varieties do in species?
Superior varieties eventually replace the ones that precede them
What is the Mechanism of Descent with Modification?
Natural selection... Superior mutants outcompete the ancestral types from which they derive
Why does the theory of natural selection fail for Victorian biologists and who pointed it out?
They believed that various forms of blending inheritance halves variation each generation..
Pointed out by Fleeming Jenkin in The North British Review 1867
What was Darwin's response to the criticism of Victorian biologists?
He had no effective answer
In turn darwin emphasized other mechanisms previously less important than natural selection
What is the theory of pangensis?
The experiences of the somatic cells are passed to the reproductive organs via the circulatory sstem
What were the other mechanisms than natural selection that Darwin proposed?
Directed mutation (new varieties induced by environmental change), saltation (macromutation), inheritance of acquired characters (pangenesis)
How did Descent with Modification become a logically consistent theory?
Medelism provided a mechanism whereby variation is preserved even when not expressed.
What is the Modern Synthesis?
The incorporation of genetics in paleontology and systematics
What are the sources of variation?
Mutations (somatic and germ line mutations)
What are somatic mutations?
Mutations that occur in the body cells. Passed on to the daughter cells after mitosis, not passed on to sexually produced offspring
What are germline mutations?
Mutations that occur in the cells of the germ line, the specialized cells that give rise to gametes. This mutation is passed onto offspring
Who were two men who defeated the idea of pangenesis?
Francis Galton and August Weissmann
What experiment did Francis Galton do to refute pangensis?
He injected tree-breeding white rabits with blood of true-breedign black rabbits withouth coat color changing in offspring
What experiment did August Weissmann do to refute pangesis?
Cut of tails of 22 generations of mice will no effect on tails of progeny
What is replica plating?
Experiment by Joshua and Esther Lederberg to prove variation exists prior to selection.
Had bacteria grown on master plate in absence of bacteriophage, then transfered colonies to same place on new plate, then colonies resistent to bacteriophage on new plate appear in same location as the experimental one
Who provided first evidence that variation exists prior to selection?
The fluctuation experiments of Luria and Delbruck
What are factors that influence gene frequences within a population?
Mutation, Migration, Selection (directional stabilizing, disruptive), Probabilistic nature of sampleing
What is the winnowing effect?
Small populations tend to have genetic bottlenecks
What is the founder effect?
If an area is colonized by a small number of individuals, there is a resulting greatly reduced genetic diversity and divergence from original population
What is the molecular clock?
Concept which allows for the estimation of degrees of relatedness among species in terms of overall levels of genetic similarity
What are the fundamental units of evolution
A Species
Why did the The Origin raise such a ruckus?
With exploration of the world outside of Europe, it was apparent that the number of species FAR exceeded number on the Ark
Who proposed the biological species concept?
Proposed in 1940 by Ernst Mayer, and along with G.G. Simpson, Fisher, Haldane, and Wright were principal architects of modern synthesis
What is the biological species concept?
species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other groups."
What are pre-zygotic isolating mechanisms?
Mating cannot occur for structural or behavioral reasons.
What are post-zygotic isolating mechanisms?
Offspring if produced are doomed to an early death or are sterile
What is the principal force promoting cohesion in a sexual species?
Gene Flow
Who was the founder of systematics?
What is the only taxonomic unit which has a precise definition?
Species... All other taxa are entirely arbitary, as are subspecies
Where do new species come from?
They come from existing ones
What are the two speciation mechanisms?
Allopatric and Sympatric
What is allopatric speciation?
Differentation of populations that are disjunct (separated spatially)
What is sympatric speciation?
Differentation of populations which co-occur
Define Panmictic populations.
A population within which the genes flow freely
How does geography effect variation?
There can be local differentiation, cline
What is local differentiation?
Variation in pockets of populations which nonetheless remain part of a single species due to gene flow
What is a cline?
A cline is when one or more characters change along a geogrpahic line
What is an example of a cline for body size?
There is an increase in body size of mammals as one goes from lower to higher latitudes
What is Bergmann's rule?
The clinal variation of increase in body size from lower to higher latitudes
What is the tension for species?
Local selection "pulling populations apart" and gene flow "holding them together"
What is the effect of a physical barrier that is introduced then removed?
Populations divide into disjunct populations, differentation occurs, re-establishment of gene flow between populations. Selection of pre or post zygotic isoloating mechanisms lead to hybrid infertility or inviability.... Then species try to invade other's ranges and selection may lead to further divergence
What is character displacement?
After following the evolution of reproductive isolation, new differentiated species re-invade each other's ranges, selection might lead to further divergence.
What is adaptive radiation?
The differentiation of a single species into many descendent species
Where have adaptive radiations been observed?
ON oceanic islands and following large scale extinction events
What is most common sympatric speciation?
An increase in chromosome number (POLYPLOIDY), instant speciation and most common for plants.
What percent of all species that ever existed are now extinct?
What are factors in causing extinction?
Background extinction (biotic interactions, ecological and evolutionary, that gradually change climates and landscapes)
And mass extinction from unique events
What is the equilibrium of species?
As the number of species increases, speciation rates sature because all ecological niches are filled, at same time extinction rates rise as species are forced into more narrow ways of life, then system balances
Who and when published Tempo and Mode in Evolution?
G.G. Simpson in 1944 this considered variation in evolutionary rates within and between lineages
How is earth's history divided into geological time scales?
Eons, Eras, Periods, Epochs
How much of Earth's history does the Precambrian represent and why is there a lack of fossils?
3/4 of Earth's history. Most precambrian organisms were soft-bodied, and older a rock, the more likely that it is metamorphic (reworked by geological processes that destroy fossils)
When was the origin of Earth and how did it form?
4500-4600 MYa. Accretion of matter surrounding sun formed earth.
How was the Moon formed?
An enormous impact 4500-4450 remelts entire surface and debris collect to form moon
What and when is the bombardment phase?
Period of large scale impacts, 4000-3800 MYA
When do mammals and dinosaurs arise?
In the Triassic
During which periods did dinosaurs rule the land and mammall remained small and insignificant?
Jurassic and Cretaceous periods
Which period witnessed the origin of flowering plants and birds?
HOw is the Cenozoic era divided?
1. Two periods (Tertiary and Quaternary)
2. Seven epochs (Paleocene, Eocene, etc.)
What is Earth's first atmosophere?
May have been mostly hydrogen gas, blown away when sun ignited
What is earth's second atmosphere and how was it formed?
Caused by outgassing associated with volcanic eruptions. Mostly CH4, and/or CO2, NH3, H2, and H20
Who proposed that life's chemical precursors could have formed spontaneously on earth?
A.I. Oparin, and J.B.S. Haldane
How did Oparin and Haldane differ in their view of the source of carbon?
Oparin-source of carbon methane, Haldance, Carbon Dioxide
What is the Urey-Miller Experiment
Organic building blocks of life were created in an experiment. Electric spark was used for lighting...Ocean was dilute soup of organics precipitated out of the atmosphere
How does one force polymerization?
Evaporation, Extreme heat
Who proposed that life might have originated elsewhere and came up with the directed transpermia hypothesis?
Francis Crick-hypothesis envisioned the transport being accomplished by intelligent beings, but non-purposeful transport is also possible - i.e., by comets, meteorites.
What is Graham Cairns-Smith's hypothesis?
The first life forms were inorganic, made of mineral crystals. These inorganic organisms served as scaffolding on which organic compounds were built. Genetic takevover where nucelic acids replaced the mineral genes
What does the lipid membrane in cells limit?
Local concentration of biological molecules which otherwise would be lost to environment
How did Oparin imagine life evolved as?
COacervates, membrane encased droplets
How do "Mineral Cells" allow for a evolution of an organism?
Tiny cavities in minerals were first cells.... Membranes/walls came after development of a real metabololism. Way of beating concentration gradient.
What were the first organisms?
Anaerobic hetetrotrophs
What are anoxic autotrophs
Self feeding organisms that obtain hydrogen from chemicals such as sulfur
What are oxygenic autotrophs?
Selffeeding organisms that obtain hydrogen from water.
What are aerobic heterotrophs?
Supplement glycolysis with citric acid cycle.
What are stromatolites?
Algal bacterial mats that were thought to be extinct till discovered in strongly haline waters of australia whose salt concentrations protected them against grazing invertebrates
What is the stratification of stromatolites?
There exists a vertical stratification. Top layer is growth surface with oxygenic autotrophs. Undermat layer contains anoxic autotrophys and facultatively aerobic heterotrophs, the oxygen depleted zone contain anaerobic heterotrophs.
How was the large scale production of oxygen caused?
Consequence of the volution of the oxygenic photosynthesis.
What is the hydrogen donor in photosynthesis and what drives the electron transport chain?
Hater, and electrons drive ETC that produces ATP
What is the first and greatest ecological crisis? Why?
The accumulation of oxygen. Oxygen is highly destructive to organic molecules, most organisms perished (some in anoxic places), few evolved by using various enzyme systems.
What has led to the rapid diversification of eukaryotes?
Who championed the theory of serial endosymbiosis?
Lynn Margulis
What are the endosymbiotic events according to SET
# 1st Endosymbiotic Event: Fusion of an archaebacteria, such as Thermoplasma with a motile eubacterium such as spirochaete. The result was a motile anaerobic eukaryotic cell.
# 2nd Endosymbiotic Event: Fusion of anaerobic eukaryote with an aerobic eubacterium such as Bdellovibrios. The result was an aerobic eukaryote possessing mitochondira.
# 3rd Endosymbiotic Event: Fusion of a motile protist with a cyanobacterium. The result was a photosynthetic eukaryotic cell which was the progenitor of green plants.
What groups have two cell layers?
Cnidarians and ctenophores
When did the evolution of eukaryotics form? What is the differences between molecular biology and paleontology
Molecular-Recounstructed phylogenies suggest that the major animal groups diverged long before the Cambrian.
Paleontology states a lack of metazoans and then dramatic increase in # and diversity at cambrian
What are trace fossils?
Worm tracks, burrows,
What are the categorizes of body plans?
1. The number of tissue layers formed during embryogenesis: 2 or 3.
2. The type of body cavity: None (aceolomate condition), Pseudocoelom, Coelom
3. The kind of symmetry manifested by the whole animal: Radial, Biradial, Bilateral
What are Ediacaran faunas?
Site of first such discovery of soft-bodied forms as well as trace fossiles.. Only modern group represented is cnidaria
What is the coevolutionary arms race?
Advances in predator "fire power" were countered by advances in victim armor. Supported by

1. Increasing presence of spines, rugosities, etc., in trilobites.
2. Shell thickening in molluscs.
Who was the historian who claimed Darwin sat on his paper several months?
John Langdon Brooks
Are mutation rates proportional to population size?
No, neutral mutations accumlate at a rate equal to the mutation rate itself and, at least to first approximation, are independent of population size.
The "mother of all mass extinctions" wipes out 96% of all species in existence at the end of the what?
What arose in what epoch?
the Pleistocene.
What is the current epoch?
What are protenoids, and who created them?
Sidney Fox and his associates were able to produce chains of amino acids , up to several hundred amino acids in length
Subsequent to the invention of oxygenic photosynthesis, the world witnessed the rise of WHAT?
What does Genomic comparison of yeast and various bacteria suggest about the tree of lif?
It is really a ring
The embryonic pore becomes what in protosomes in comparison to deutrosomes?
What is the clevage pattern of Spiralians?
What is the cleaveage pattern for mammals?
What are some characteristics of Cephalopods?
Fast swimmers, mantle allows jet proposion
How do octopi communicate?
Through the changing of color by specialized organs called chromatophores
What is the sharp feeding structure of the mollusc?
What is the life cycle of trichhinosis?
Person eats meat infected with larvae. Larvae activiated in digestive track, emerge from their cysts, attach to intestinal wall, feed, and then inter bloodstream to be carried to muscles, forming cysts.

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