Bio 182 Exam 2
In a certain population the heterozygous individuals have the highest fitness (W) and average 20 offspring produced. If the homozygous recessive genotype has a relative fitness of 0.4, how many offspring on average would each homozygous recessive individual produce?
8
Escherichia coli and Clostridium acetobutylicum are reported to be derived from a common ancestor. They have some similar, but not identical gene sequences. What is the best explanation for this difference in genetic coding?
After the two species diverged, the genes accumulated random mutations that resulted in similar, but not identical gene sequences
If a population satisfies the Hardy-Weinberg equilibrium model, what can you assume about that population?
Allele and genotype frequencies are stable
The fact that there is two separate species of ground squirrel, Ammospermophilus harrisii on the south rim & Ammospermophilus leucurus on the north rim is an example of what type of speciation?
Allopatric speciation
Two ways a new species can be formed
Anagenesis, Cladogenesis
What pattern of selection would be most likely to produce a speciation event via cladogenisis? What phenotypes are being selected against under this model of selection?
Disruptive selection, the median phenotypes (the ones in the middle)
8 categories of taxonomic hierarchy
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
4 bya
Earth had cooled enough for outer layers to solidify and oceans to form
What idea is shared by both Lamarck's and Darwin's theories of evolution?
Environmental changes can lead to the modification of traits
True or False Fossils are primarily found in igneous rocks
False
True or False Inland species are more likely to be preserved than marine species
False
True or False Organisms that lived very long ago are more likely to be found as fossils than organisms that lived relatively recently
False
True or False The hard parts of organisms are preserved in their original form in fossils
False
Extinct/living members of the horse family
Fossil record
Homologies
Fundamental similarity due to descent from a common ancestor
What phenomena tends to increase genetic variation in a population?
Gene flow
All of the alleles for every gene for all individuals in a given population is referred to as
Gene pool
What mechanism leads to changes in allele frequencies due to random chance?
Genetic drift
When allelic frequencies change due to random chance it is called what? What size populations is this evolutionary driver most prevalent?
Genetic drift, small populations
Evolution
Heritable change in one or more characteristics of a population or species from one generation to the next
Gill ridges in human and fish embryos
Homology
Mouthparts of different insects
Homology
Similarities among various species that occur because they are derived from a common ancestor is called what?
Homology
Explain the 4 stages in the "Four stage hypothesis for the origin of life"
1. Nucleotides and amino acids produced prior to the existence of cells 2. Nucleotides and amino acids became polymerized to form DNA, RNA and proteins 3. Polymers became enclosed in membranes 4. Polymers enclosed in membranes acquired cellular properties
Does gene flow increase or decrease genetic differences between populations?
decreases genetic differences between populations
Scientist believe that the formation of organic polymers, like RNA and DNA, had to move from the watery environment of the seas to solid surfaces or evaporating tidal pools because
dehydration is necessary for the formation of large organic polymers, too much water competes with dehydration
Most frog species have a distinct tadpole life stage. However, microhylids of Australia and New Guinea do not have a free-swimming tadpole stage. The tadpole forms inside the egg, completes metamorphosis, and hatches from the egg. This would be an example of a
developmental homology
Which of the three general outcomes of natural selection is most likely to lead to new speciation events via anagenesis?
disruptive/diversifying
What aspect of Life evolved through speciation?
diversity
The event called the Cambrian Explosion resulted in an abrupt increase in
diversity of major animal groups
Allopatric speciation
due to geographic isolation
What field of study uses geographic distribution of extinct and living species to determine patterns of evolution? a)Biology. b)Geology. c)Palentology. d)Geneology. e)Biogeography.
e)Biogeography.
Under the ___________ , species are identified based on their unique habitat requirements
ecological species concept
A coral species that currently inhabits a single reef off the coast of Indonesia would be considered:
endemic
phylogeny
evolutionary history of a species or group of species
Hybrid inviability
fertilized egg cannot progress past an early embryo
A confused frog deposits its sperm onto a toad's eggs as they are being laid. No offspring develop because the frog's sperm are unable to penetrate the toad's egg. This is an example of
gametic isolation
In a small population, both _________ and __________ would violate the conditions of Hardy-Weinburg equilibrium
gene flow, genetic drift
The most important concept in the field of population genetics is
genetic variation
What are the two parts of any Latinized binomial name?
genus and species
According to the concept of ___________, species evolve continuously over long spans of time.
gradualism
American sycamore (Platanus occidentalis) and European sycamore (Platanus orientalis) are tree species that will interbreed if planted nearby but will not normally interbreed because they occur on different continents. This is an example of
habitat isolation
The term evolution is used to describe
heritable changes in characteristics of a population from one generation to the next
If goats are crossed with sheep, embryos will form but cease development and spontaneously abort. This is an example of
hybrid inviability
A liger is a result from a male lion and a female tiger. Male ligers cannot produce offspring. This is an example of
hybrid sterility
Hybrid breakdown
hybrids viable and fertile but subsequent generations have genetic abnormalities
Changes that have occurred in living organisms over the past four billion years are due primarily to
interaction of genetic and environmental changes
Hybrid sterility
interspecies hybrid viable but sterile
Gene flow
is genetic exchange with another population
Half-life
length of time required for exactly one-half of original isotope to decay
During spring time in Maine, male moose often enter a cow pasture and begin calling to the female cows. The moose may even try to mount the female but the male genitalia do not fit properly inside the female genitalia. This is an example of
mechanical isolation
Species
members of the same species are capable of interbreeding to produce viable and fertile offspring
What is the biological species concept?
members of the same species are capable of interbreeding, producing viable offspring, and cannot produce viable offspring with members of other species
Evolution, viewed on a small scale, as it relates to changes in a single gene or allele frequency in a population over time, is called
microevolution
2 views (levels) of evolution
microevolution and macroevolution
1.2 bya
multicellular eukaryotes
Ultimate sources for all genetic variation
mutation
Which mechanisms of evolution is the most important?
natural selection because it is the only process that promotes adaption
Sympatric speciation
occurs in populations that live in the same geographic area
Speciation
one species splits into two or more species
Natural Selection
organisms with certain inherited characteristics are more likely to survive and reproduce than are individuals with other characteristics (survival of the fittest)
What is the Hardy-Weinberg formula?
p^2+2pq+q^2=1
What is the fossil record?
preserved remains of past life on Earth
~3.5 bya
prokaryotes evolved
The origin of the mitochondrion and chloroplast by endosymbiosis, hypothesizes that these organelles originated by
prokaryotic cells that became internal symbionts within an early eukaryotic cell
What was the major flaw in Lamarck's theories?
proposed that by using or not using its body parts, an individual may develop certain traits that it passes on to its offspring, thus, acquired traits are inherited
Relative fitness
relative likelihood that a genotype will contribute to the gene pool of the next generation as compared to other genotypes-- measure of reproductive success
Fitness is a measure of the _______ of a particular genotype in a population
reproductive success
Molecular homology can be compared by analyzing the
sequences of amino acids of various proteins in different species
Anagenesis
single species evolves into a different species
4.6 bya
solar system began
What does cladistics compare?
species based on evolutionary relationships
In _____ selection, individuals intermediate in a phenotypic distribution have greater reproductive success.
stabilizing
Population genetics
study of genes and genotypes in a population
Cladograms include in the phylogenetic tree shared primitive characters and shared derived characters. The derived characters can also be called ______ while the primitive characters can also be called __________.
synapomorphy; symplesiomorphy
____________ groups are based on hypotheses regarding evolutionary relationships derived from _____________
taxonomic, systematics
Two species of salamander have similar ranges, but one breeds from January to March, while the second one breeds from March to May. This is an example of
temporal isolation
Two-stage hypothesis for the origin of Eukaryotic cells
the infolding of the plasma membrane of a prokaryotic cell to form the endomembrane system
When choosing among competing cladograms, the preferred hypothesis is the one that is the simplest for all characters and their states. This is also known as
the principle of parsimony
Biogeography
the study of the geographic distribution of species
Gene pool
the total collection of alleles in a population at any one time
Sympatric speciation differs from allopatric speciation because in sympatric speciation
there are no physcial barriers against interbreeding.
The gene pool of the next generation is derived from
those individuals of a population that reproduce and have viable offspring
Convergent evolution
two different species from different lineages show similar characteristics because they occupy similar environments
When observing the skeleton of a snake, you see the remains of hip and hind leg bones associated with four legged animals. These bones are called...
vestigial structures
Explain the difference between the punctuated pattern and gradual pattern as to how it pertains to the pace of evolution.
In the gradual pattern, big changes are steady throughout time but during the punctuated pattern, there's long periods of equilibria (little change) followed by brief periods of rapid change
How can genetic drift influence allele frequencies in a population?
It favors either the loss or fixation of an allele
What is true of a fossil that is classified as a "transitional form"?
It has some of the traits of its ancestors and some of the traits of its descendants
Fossil Records
Paleontologists (scientists who study fossils) have discovered many transitional forms that link past and present
Selective Breeding
Programs and procedures designed to modify traits in domesticated species
What type of organisms were the earliest eukaryotes?
Protists
Which macromolecule did the majority of scientists favor as the "first" to be found in protobionts?
RNA
Taxonomy
Science of describing, naming, and classifying extant and extinct organisms and viruses
Different types of cattle
Selective Breeding
Kale, broccoli, and cabbage
Selective Breeding
The fact that we were able to get kale, broccoli, brussels sprouts, cabbage, & cauliflower as extreme different phenotype of the wild mustard plant demonstrates what principle? (it is one of the 5 major pieces of evidence for evolution presented in class)
Selective Breeding or Artificial Selection
primitive character
Shared by two or more different taxa and inherited from ancestors older than their last common ancestor
derived character
Shared by two or more species or taxa and has originated in their most recent common ancestor
Homology
Similarities among various species that occur because they are derived from a common ancestor
2.1 bya
Single-celled eukaryotes
True or False A phylogenetic tree shows the hypothesized evolutionary relationships among organisms, meaning that its structure can be revised and changed as new information about those relationships becomes known
True
True or False Fossils found in lower rock layers are older than those found in upper layers
True
True or False Fossils include the preserved impression of footprints of past life
True
True or False Organisms with hard body parts are more likely to be preserved than are those composed soft tissues
True
True or False Species that existed over a larger area are more likely to be preserved than species existing over a smaller area
True
True or False The fossils of larger organisms are more likely to be found than the fossils of smaller organisms
True
13.7 bya
Universe began with the Big Bang
Protobionts are thought to be the first nonliving structures that evolved into living cells. A critical characteristic of a protobiont that is found in both modern day prokaryotes and eukaryotes is
a boundary membrane that separates external from internal environments
Cladogenesis
a species diverges into two or more species
What are the 4 major steps in the "Four-Stage Hypothesis for the Origin of Life"?
a) Abiotic formation of organic monomers b) Abiotic synthesis of polymers c) Formation of pre-cells (wrapped in a membrane/boundry) d) Achievement of Self-replication
~500 mya
colonization of land
A mutation arises in an individual that decreases its fitness. This means that this individual's
contribution to the gene pool of the next generation will decrease
Cacti in the deserts of southwestern North America and some euphorbs of the deserts of Africa, have barrel-shaped stems, short-lived leaves, and spines, yet these two types of plants are from different evolutionary lineages. This is an example of
convergent evolution
During spring time in Maine, male moose often enter a cow pasture and begin calling to the female cows. The moose may even try to mount the female but the male genitalia do not fit properly inside the female genitalia. This is an example of a) Temporal isolation b) Gametic isolation c) Hybrid breakdown d) Mechanical isolation e) Habitat isolation
d) Mechanical isolation
Which is the proper binomial name for humans? a)homo sapiens b)homo Sapiens c)Homo Sapiens d)Homo sapiens
d)Homo sapiens
What 2 observations the theory of natural selection based off of? What conclusion (inference) can be made from these two observations?
-All species tend to produce excessive numbers of offspring. -Organisms vary, and much of this variation is heritable. Conclusion: Unequal reproductive success (natural selection)
Identify the 5 pieces of evidence for evolution we discussed in class.
-Fossil records -Biogeography -Selective breeding -Homologies -Convergent Evolution
Conditions for Hardy-Weinberg Equilibrium?
-No new mutations occur -No natural selection occurs -The population is so large that allele frequencies do not change due to random sampling error -No migration occurs between different populations -Random mating
Two main points in The Origin of Species.
-Organisms inhabiting Earth today descended from ancestral species -Natural selection is the mechanism for descent with modification
Postzygotic barriers
-Reduced hybrid viability -Reduced hybrid fertility -Hybrid breakdown
Things that could affect the fossil record & create bias
-Size: smaller organisms are less likely to be discovered than bigger organisms -Number: species that existed in greater # or over a larger area are more likely to be preserved -Anatomy: organisms with hard body parts are more likely to be preserved than animals composed of soft tissue -Environment: inland species less likely to be preserved than those that lived in a marine environment or near the edge of the water -Time: organisms that lived relatively recently or existed for a long time are more likely to be found than organisms that lived a long time ago or that lived for a short amount of time
Prezygotic barriers
-Temporal isolation -Habitat Isolation -Behavioral Isolation -Mechanical Isolation -Gametic Isolation
3 types of homologies that are seen among species
-anatomical: Same set of bones in the limbs of modern vertebrates has undergone evolutionary change for many different purposes -developmental: Species that differ as adults often bear striking similarities during embryonic stages -molecular: Evolutionary relationships among species can be determined by comparing genes and proteins of different organisms
Explain the three general outcomes (patterns) of natural selection
-directional: individuals at one extreme of a phenotypic range have greater reproductive success in a particular environment -disruptive/diversifying: favors the survival of two or more different genotypes that produce different phenotypes -stabilizing: favors the survival of individuals with intermediate phenotypes
Protists
-eukaryotes that are not fungi, animals or plants -mostly unicellular -ancestral to all other eukaryotes
What type of animal found in the Galapogos Islands did Darwin base many parts of his theory of evolution via natural selection? What was the characteristic that varied among these animals?
-finches -beaks
The three observations about the natural world Darwin expressed in the book
-life shows rich diversity -there are similarities in life that allow the classification of organisms into groups nested within broader groups (patterns of similarities) -organisms display many striking ways in which they are suited for their environments (organisms are suited to their environments)
3 main mechanisms of evolutionary change?
-natural selection -genetic drift -gene flow
Endosymbiosis
-refers to one species living inside another host species and -is the process by which eukaryotes gained mitochondria and chloroplasts.
Blue flower color (B allele) is dominant to white (b allele). If a population of plants contains white flowers (bb) at a frequency of 0.04, what is the frequency of the blue flower allele (B)?
.8 or 80%
Fitness is a measure of reproductive success. If an individual with genotype BB produces 6 offspring, and a heterozygous individual (Bb) produces 10 offspring, and a third individual with genotype bb produces 5 offspring, what is the fitness value for the individual with BB genotype?
0.6
In the Hardy-Weinberg equation, p + q =_______, where p and q represent _________.
1, allele frequencies
Genotype Qq produces 10 offspring per year. Genotype QQ has a fitness value of 0.4 and genotype qq has a fitness value of 0.2. How many offspring does genotype qq produce each year?
2
To analyze genetic variation in populations, one approach is to consider the frequency of alleles. When calculating an allele frequency for a diploid species, how many alleles are present for each gene?
2
In the Hardy-Weinberg equation , the genotype frequency of heterozygotes is represented by
2pq
When was the earth formed
4.6 billion years ago
How many mass extinctions have been identified in the fossil record?
5
You are excited because you just purchased a male guppy that has red, blue and green colors on its fins and tail. Your guppies at home do not have this combination of colors. You place the new male in with three females for mating purposes. After three weeks you have many new baby guppies and with the new color combination. This is an example of which type of selection?
Artificial
Three Domains of Life
Bacteria, Archaea, Eukarya
During the Beagle journey, Darwin visited islands, allowing him to compare island species with continental species. In terms of framing his theory of evolution, why was this significant?
Because the island species had both similarities to their continental ancestors and unique adaptations to their island environments
"If you don't know the Blue Footed Boobie boogie, then you don't get no Blue Footed Boobie booty"(--Dr. S) Is an example of what type of reproductive barrier?
Behavioral isolation
Darwin's finches
Biogeography
Endemic island species
Biogeography
What major event began ~540 million years ago, lasted about 10 million years, and resulted in all the evolution of all the major phyla of animals?
Cambrian Explosion
Scientist that proposed the current two-part naming system for each species
Carolus Linnaeus
Who was the scientist that proposed the current taxonomic system that uses Latinized binomial names?
Carolus Linnaeus
The scientist that wrote "The Origin of Species"
Charles Darwin
The process by which the major land masses have shifted their positions, changed shapes and separated from each other, is known as
Continental drift
Camera eye of squids and humans
Convergent evolution
Wings of butterflies and birds
Convergent evolution
When humans are developing in utero they have characteristics that are not found in the fully developed infant. Which type of homology does this typify?
Developmental
phylogenetic tree
Diagram that describes phylogeny
Radioisotope dating
Measure amount of a given isotope as well as the amount of the decay product
Population
Members of the same species that are likely to encounter each other and thus have the opportunity to interbreed
The early Earth reducing atmosphere is thought to have lacked which of the following gases?
O2
How did Darwin develop his theory of evolution?
Observation
The scientific name for the golden crayfish is Orconectes luteus. Based on this information, the crayfish is a member of what genus?
Orconectes
Names of time periods where the mass extinctions took place
Ordovician, Devonian, Permian, Triassic, and Cretaceous
Study of the origin of life has resulted in the breakdown of cellular development into overlapping stages, beginning with the synthesis of precursor molecules for the synthesis of nucleotides and amino acids and ending in polymers enclosed in membranes acquiring cellular properties. Which of these stages were a focus of study for Miller and Urey in their FIRST experiment?
Stage 1: Nucleotides and amino acids were produced prior to the existence of cells
Who was the scientist who did the famous experiment that validated the reducing atmosphere hypothesis for the synthesis of primitive organic monomers?
Stanley Miller
What is the name of the scientist who is credited with the punctuated equilibrium theory of the pace of speciation?
Steven J. Gould
Systematics
Study of biological diversity and the evolutionary relationships among organisms
What is the name of the famous book by Charles Darwin that lays out his theory of Natural Selection?
The Origin of Species
To prepare for a hiking trip in the Appalachian mountains, you buy several field guides for the region from a used bookstore. You notice that the older guides list a single species of tiger swallowtail butterfly, Papilio glaucus, and an Appalachian morph of this species. However, the newest guide list two separate species, P. glaucus and P. appalachiensis. The authors of this guide state that the biological species concept was used in determining their classifications. What do you think led them to list two separate species of tiger swallowtail?
The discovery that P. glaucus and P. appalachiensis do not interbreed in the wild
Macroevolution
The process of evolutionary changes that result in formation of new species and groups of species
What would be the best indication that two individuals belong to the same species?
They can mate and produce offspring that can also mate
The Northern leopard frog (Rana pipiens) and Southern leopard frog (Rana utricularia) are morphologically similar, but their mating calls sound very different. Based on this, what is the best explanation for why these frogs are considered separate species?
They have undergone behavioral isolation which prevents them from interbreeding
What are the two key observations and conclusion of Darwin's theory of Natural Selection?
a) Overproduction of offspring leads to competition. b) Variation exists among individuals in the population and is heritable. c) There is unequal reproductive success. (Those individuals with traits best suited to the local environment generally leave a larger share of surviving, fertile offspring)
In a population of 100 four o'clock plants, there are 50 red-flowered plants with genotype CRCR, 30 pink-flowered plants with genotype CRCW, and 20 white-flowered plants with genotype CWCW. Match the correct frequencies for the following alleles and genotypes. a. CRCR= b. CRCW= c. CWCW= d. CR= e. CW=
a. CRCR=0.5 b. CRCW=0.3 c. CWCW=0.2 d. CR=0.65 e. CW=0.35
A gene pool consists of
all alleles for all genes in a population
Approximately 3.5 million years ago the Isthmus of Panama formed. This new landmass severed the connection between the Pacific Ocean and the Caribbean Sea. An ancestral fish population (porkfish) was split in two by this event; the two populations no longer interbreed and are two distinct species. This type of speciation is called
allopatric speciation
When a species consisting of a single large population slowly evolves over many generations into a new species, this an example of
anagenesis
began ~540 mya
animals
~2.7
atmospheric oxygen
What is not true of the process of natural selection? a) Individuals that are better adapted to their environments tend to produce more offspring than less well adapted individuals. b) For natural selection to operate, individuals within a population must produce equal numbers of surviving offspring. c) If the environment changes, individuals that previously had a reproductive advantage may now be at a reproductive disadvantage. d) Alleles that lead to better adapted individuals will tend to increase in a population over time.
b) For natural selection to operate, individuals within a population must produce equal numbers of surviving offspring
Which would be most likely to be fossilized? a)a common large worm b)a common thick-shelled crustacean c)an herbaceous plant that is only found at very high altitudes d)a rare, desert-dwelling lizard
b) a common thick-shelled crustacean
What phenomenon would violate the conditions for Hardy-Weinberg equilibrium? a)The population is isolated from other populations. b)Females select males based on secondary sex traits. c)The population is large. d)No genotypes within the population have a reproductive advantage. e)Genetic drift within the population does not change allele frequencies
b)Females select males based on secondary sex traits.
Over generations in a population, individuals with higher fitness values will
become more prevalent in the population
A group of individuals that can interbreed in nature and produce viable offspring would be considered to be a species according to the
biological species concept
If you know that in a population q=0.5, what would be the expected frequency of heterozygotes in this population based on Hardy-Weinberg equation? a) .1 b) .25 c) .5 d) .75 e) .9
c) .5
The origin of the mitochondrion and chloroplast by endosymbiosis, hypothesizes that these organelles originated by a)the fusion of two archean cells to form an early eukaryote. b)the absorption of RNA from prokaryotic cells. c)prokaryotic cells that became internal symbionts within an early eukaryotic cell. d)the uptake of free DNA from the environment. e)prokaryotic cells being engulfed and becoming external symbionts within an early bacteria cell.
c)prokaryotic cells that became internal symbionts within an early eukaryotic cell.
Genetic drift
changes allelic frequency due to random chance
Microevolution involves ___
changes in a population's gene pool
Microevolution
changes in a single gene in a population over time
