124 terms

Bio Exam III Questions

A geneticist studied a grass population growing in an area of erratic rainfall and found that plants with alleles for curled leaves reproduced better in dry years, and plants with alleles for flat leaves reproduced better in wet years. This situation would _____.
preserve the variability in the grass population (Both types survive in approximately equal numbers over several years.)
Which person has the highest evolutionary fitness?
a man who lives to be 68 and has 7 children and 15 grandchildren
(Production of fertile offspring is key to evolutionary fitness)
Thirty people are selected for a long-term mission to colonize a planet many light years away from Earth. The mission is successful and the population rapidly grows to several hundred individuals. However, certain genetic diseases are unusually common in this group, and their gene pool is quite different from that of the Earth population they have left behind. Which of the following phenomena has left its mark on this population?
Founder Effect
If a volcanic eruption killed all of the lizards on an island except for a tiny group of survivors, this event would probably cause _____.
Genetic drift through bottle neck effect
The ultimate source of all new alleles is....
mutation in parent cells (asexual organisms) or in cells that produce gametes (sexual organisms).
Which of the following thinkers argued that organisms tend to produce many more offspring than the environment can support, leading to a struggle for existence, an argument that later influenced Charles Darwin's ideas of natural selection?
Thomas Malthus
If members of a population have traits that are both heritable and variable among individuals, then _____.
advantageous traits will probably become more widespread in subsequent generations
(Those individuals whose inherited characteristics fit them best to their environment are likely to leave more offspring than are less fit individuals.)
Which of the following will tend to produce adaptive changes in populations?
Natural Selection
Scientists have warned doctors of the danger of their increasing use of antibiotics for treating minor illnesses. They are concerned because _____.
strains of bacteria that are resistant to these drugs will become more widespread
(A new mutation that happens to be beneficial can increase in frequency in a bacterial population very rapidly. If a single individual in the population harbors a mutation that renders it resistant to an antibiotic, there may be millions of resistant bacteria a few hours after antibiotic treatment begins.)
Which genotype relative to the sickle-cell allele has the greatest reproductive success in regions where malaria is a common disease?
The heterozygous genotype (Heterozygotes are protected from severe cases of malaria and do not develop sickle-cell disease. This phenomenon is called heterozygote advantage and tends to balance out the selection against the allele caused by illness in homozygous recessive individuals. Thus, the allele is fairly frequent in populations where malaria is or has been common.)
When a horse and a donkey mate, they produce infertile hybrids called mules. According to the _____ species concept, horses and donkeys are _____.
Biological.....Different Species (If you apply the biological species concept to this situation, the only conclusion is that horses and donkeys are separate species because their offspring are infertile.)
Biological Species Concept
"species are groups of interbreeding natural populations that are reproductively isolated from other such groups."

Explains why the members of a species resemble one another, i.e. form phenetic clusters, and differ from other species.

When two organisms breed within a species, their genes pass into their combined offspring. As this process is repeated, the genes of different organisms are constantly shuffled around the species gene pool. The shared gene pool gives the species its identity. By contrast, genes are not (by definition) transferred to other species, and different species therefore take on a different appearance.
Ecological Species Concept
a concept of species in which a species is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognize as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters.
Temporal isolation
Individuals of different species reproduce at different times. (Cicadas who emerge every 17 years to reproduce, while siblings species emerges on a 13 year cycle)
Mechanical isolation
Individuals cannot mate or pollinate because of physical incompatibilities. (Black sage and white sage have different sized anthers which requires small bees for black sage and large bees for white sage)
Behavioral Isolation
Individuals of different species ignore or do not get the required cues for sex. (females recognize the singing, wing spreading, or bobbing of a male of her species as an overture to sex. Females of different species usually ignore this behavior)
Ecological Isolation
Individuals of different species live in different places and never meet up. (Salamanders living in high mountain streams do not mate with salamanders living in valley streams.)
Gamete Incompatibility
Reproductive cells meet up, but no fertilization occurs. (reason some animals have their eggs fertilized by the release of free-swimming sperm in an aquatic habitat)
Hybrid Inability
Hybrid embryos die early or new individuals die before they can reproduces.
Hybrid Sterility
Hybrid individuals or their offspring do not make functional gametes. (Horses and donkeys mating to make sterile Mules)
What is the most common mode of speciation?
Allopatric Speciation
Speciation occurs when what ends?
Gene Flow
What can happen that causes speciation to occur in an instant?
A change in chromosome number.
Cells that have three or more sets of chromosomes characteristic of their species.
a new species that arose by chromosome multiplication in one parent species; occur spontaneously in nature but can be induced artificially by treating a plant's seeds or buds with colchicine.
Have a combination of chromosome sets from different species
Sympatric Speciation
A speciation model in which speciation occurs in the absence of a physical barrier (like by polyploidy in flowering plants)
Parapatric Speciation
Occurs when one population extends across a bread region encompassing diverse habitats. The different habitats exert distinct selection pressures on parts of the population, resulting in divergences that lead to speciation (the giant walking worm and the blind velvet walking worm hybrid's are sterile keeping the two species separate identity in the absence of a physical barrier between their habitats)
major evolutionary novelty stems from adaptation of existing structures (feathers of bird wings for flight from dinosaurs using feathers for insulation)
Adaptive Radiation
Burst of divergences from a single lineage...from a set of new niches (Hawaiian Honeycreepers)
The joint evolution of two closely interacting species; each species is a selective agent that shifts the range of variation in the other (Orchid's nectar only can be retrieved by the hawkmoth bc of their long proboscis which in turn pollinates the orchid)
Evolutionary Adaptation
A trait (a heritable aspect of form, function or behavior) that improves an individual's odds of surviving and reproducing in its prevailing environment.
What type of cells did prokaryotic cells give rise to?
1) Bacteria
2) the shared ancestors of archaens and eukaryotes
What did Lynn Margulis propose?
The idea of endosymbiosis
an intimate, permanent ecological interaction in which one species lives and reproduces in the other's body to benefit one or both.
What are the four distinguishing characteristics of all members of Phylum Chordate?
1) Arod of stiff but flexible connective tissue (notochord) that extends the length of the body and supports it.
2) Dorsal hollow nerve cord that parallels the notochord
3) Gill slits open across the wall of the pharynx (the throat region)
4) A muscular tail extends beyond the anus
Invertebrate chordates that briefly swim as larvae, then metamorphase into an adult that has a secreted covering or tunic....only retain gill slits, while the other characteristics leave. They are filter feeders
Invertebrate chordates with fishlike body that retain all chordate characteristics. Have an eyespot at the end of the nerve cord that detects light, but they do not have a brain or sensory organs. Like vertebrates, they have segmented muscles.
Only modern animals with a cranium but no backbone; soft-bodied, jawless fishes with a notochord that supports the body; sensory tentacles help them detect food; paired ears that detect vibrations; pair of eyes with no lens and vision is poor/nonexistent; secrete a gallon of slimy mucus when threatened.
A modern jawless fish; cartilaginous cranium and backbone, but no fins or jaws; parasites that attach to other fishes and feed on their tissues.
What major traits arose in reptiles, birds, and mammals that did not exist in amphibians?
They are amniotes, have highly efficient kidneys, and waterproof skin.
produce eggs having four extra-embryonic membranes:
Chorion, Allantois, Yolk Sac, and Amnion.
What are the four major groups of modern reptiles?
1) Turtles
2) Lizards and Snakes
3) Crocodilians and Birds
4) Tuataras ("peaks on the back"; walk like salamanders and have some amphibianlike brain structures; have a third eye on their forehead)
Cartilaginous fishes
Marine sharks and rays; have large fins, a skeleton of cartilage, and five to seven gill slits on each side; teeth are modified scales hardened with bone and dentin which grow in rows and are continually shed and replaced.
What is the most diverse vertebrate group?
Ray-Finned Fishes
Ray-Finned Fishes
Flexible fin supports, derived from skin, and thin scales (gars, paddlefish, sturgeons, eels, seahorses, puffers, salmon, bass, tuna, most "dinner plate" fish)
Lobe-Finned Fishes
Coelacanths are the only modern group.

Ventral fins are fleshy extensions of the body wall and have internal skeletal elements that support them; have gills.
Have gills and lunglike sacs (modified outpouchings of the gut wall). They gulp air and oxygen diffuses from the sacs into the blood.
Evidence suggests that ______ and __________ are the closest living relatives of tetrapods (four-legged walkers).
lungfishes and lobe-finned fishes
A splinter population is separated from the main population of a species. Each of the populations begins to evolve independently. When has speciation occurred?
Genetic changes establish reproductive barriers between the two populations.
The first vertebrate with a head and skull probably resembled a what?
Most amphibians have two key characteristics that tie them to water or at least damp habitats. What are they?
use of skin for gas exchange and soft, jelly-covered eggs
The tuatara is a lizard-like reptile found only in New Zealand today, the last surviving lineage of a large group of reptiles that were contemporaries of the dinosaurs. Which of the following traits would you expect the tuatara to possess?
amniotic egg and scaly skin
Which describes the most advanced (derived) mammal?
a hairy animal that gives birth to well-developed live young
What do bio-geographers study?
Continental drift, patterns in world distribution of species, and mainland and island biodiversity.
Evolution _________.
Is heritable change in a line of descent and may occur by natural selection.
Which formed first, Pangea or Gondwana?
Geologic change has occurred repetitively in Earth's history.
What did Cuvier contribute to evolution science and Darwin's thinking?
compared fossils and living organisms; though abrupt changes in the fossil record meant times of mass extinction. Founder of the idea of Catastrophism.
What did Lamarck contribute to evolution science and Darwin's thinking?
Offspring inherit traits that parents acquire through their lifetime...life drives to perfection.
What did Lyell contribute to evolution science and Darwin's thinking?
"Theory of Uniformity"
Geological history of the regions that Darwin would encounter.... catastrophes were not necessary to change the Earth, erosion could do it over time.
What did Wallace contribute to evolution science and Darwin's thinking?
Wrote an essay outlining Darwin's Theory. Known as the "Father of Biogeography"
What did Darwin contribute to evolution science?
Variations in traits can influence ability to secure resources; "Natural Selection"
What did Malthus contribute to evolution science and Darwin's thinking?
Correlated population size with famine, disease, and war...led him to conclude that we reproduce beyond capacity and thus compete for resources.
Genetic Drift
A random change in allele frequencies over time brought about by chance.
Genetic drift is exemplified in ______ populations.
Individuals don't evolve, ________ do.
_________ is the original source of new alleles.
Natural selection can only occur in a population when there are ______.
differences in forms of heritable traits.
Directional selection ________.
shifts allele frequencies in one direction only.
Disruptive selection __________.
does not favor intermediate forms of a triat.
Sexual selection, such as competition between males for access to fertile females, frequently influences aspects of body form and leads to _________.
sexual dimorphism
The persistence of malaria and sickle-cell anemia in a population is a case of __________.
Balanced polymorphism
________ tends to keep populations similar to one another.
Gene Flow
What are the five conditions of genetic equilibrium?
1) Mutations never occur
2) Population is infinitely large
3) Population stays isolated from all other populations of the same species
4) All individuals mate at random
5) All individuals survive to produce the same number of offspring.
Microevolution is when there are small scale changes in a populations' _______________.
allele frequencies
What is the Hardy-Wineburg Equation?
p^2 + pq + q^2 = 1.0
Occurs when all the individuals of a population have become homozygous for some allele; means allele frequency will never change.
a drastic reduction of the population size brought about by severe pressure.
Founder effect
a form of bottlenecking; change in allele frequency that occurs after a few individuals establish a new population.
Gene Flow
Allele frequencies change owing to immigration, emigration, or both (Alexander the Great bringing green eyes from Greece to India)
An abundance of ______ in the atmosphere would have prevented the spontaneous assembly of organic compounds on early earth.
The prevalence of iron-sulfide cofactors in living organisms may be evidence that life arose _________.
near deep-sea vents
RNA in ribosomes can catalyze formation of peptide bonds. THis supports the hypothesis that ______.
RNA was the first template for protein synthesis
Simualtions of conditions on early tidal flats support the hypothesis that _______.
clay can facilitate the assembly of polypeptides.
The evolution of _________ resulted in an increase in the levels of atmospheric oxygen.
The noncyclic pathway of photosynthesis.
Mitochondria are probably descendants of __________.
Aerobic Bacteria
Infoldings of the plasma membrane into the cytoplasm of some prokaryotes may have evolved into the _______.
Nuclear Envelope and ER Membranes
What is the Chronological order of evolutionary events (Life's Origins)?
1) The Big Bang
2) Origin of proto-cells
3) Emergence of the cyclic pathway of photosynthesis
4) Emergence of the noncyclic pathway of photosynthesis
5) Origin of Mitochondria
6) Origin of Chloroplasts
Protein digestion begins in the ______.
Most nutrients are absorbed in the __________.
Small intestine
Bile has roles in ________ digestion and absorption.
Monosaccharides and amino acids are both absorbed from the gut _______.
at membrane proteins
The pH is lowest in the _______.
Stomach (low means most acidic)
Most water that enters the gut is absorbed across the lining of the __________.
small intestine
_________ are inorganic substances with metabolic roles that no other substance can fulfill.
Makes bile
compacts undigested residues
secretes most digestive enzymes
absorbs most nutrients
small intestine
secretes gastric fluid
stores, secretes bile
Arteries carry blood...
away from the heart
What is unique about blood in pulmonary arteries compared with blood in other arteries?
It is loaded with carbon dioxide.
During ventricular systole, blood flows _____.
from the left ventricle into the aorta, and from the right ventricle into the pulmonary arteries
Whether there is a net flow of fluid into or out of a capillary at a given point along its length depends upon
the balance between blood pressure and osmotic pressure.
The epiglottis is a
flap of cartilage that flips down to cover the entry to the trachea during swallowing.
How is the stomach lining protected from the caustic acid pH of its contents?
Mucous cells secrete a protective lubricant into the stomach.
Imagine that you have eaten a meal containing the following nutrients: Protein, polysaccharide, disaccharide, nucleic acid, amino acid.

Which would be absorbed without enzyme digestion?
Amino acid (Amino acids are the monomers that combine to become protein.)
How does the enzyme lipase work in digestion?
It works with bile salts to hydrolyze fat to fatty acids and glycerol.
What is the main digestive function of the pancreas?
to produce digestive enzymes and a bicarbonate buffer.
The universal blood donor is ______.
The universal blood acceptor is _________.
Cells directly exchange substances with ________.
interstitial fluid
Blood flows directly from the left atrium to ________.
the left ventricle
Blood pressure is highest in the _______ and lowest in the _______.
arteries; veins
At rest, the largest volume of blood is in _________.
At the start of a capillary bed (closest to arterioles), ultrafiltration moves _______.
water, ions, and small solutes into interstitial fluid.
Complement proteins _____.
form pore complexes and promote inflammation
________ trigger immune responses.
Antibodies are _________.
1) Antigen Receptors
2) Made only by B cells
3) Proteins
Antibody-mediated responses work against _______.
extracellular pathogens and extracellular toxins
_______ binding antigen triggers allergic responses.
______ are targets of cytotoxic T cells.
Virus-infected body cells or tumor cells