BIO 182- EXAM 2 prep

asexual reproduction

- it directs cells to divide and develop into new tissues and organs. This process takes time and energy, but these resources go directly into the production of offspring -a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes -the offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent -carries a nearly identical set of alleles as its parent does

homologous chromosomes

-a chromosome in which most animals and plants are diploid, such that their nuclei contain two copies of each chromosome which is called homologous chromosome -they contain the same genes arranged in an identical order

Occurrence of sexual reproduction

-a diploid cell must cut its number of chromosomes in half before fusing with another cell. Otherwise, organisms would double their number of chromosomes each generation -includes a division of the nucleus that halves the number of chromosomes -A diploid organism inherits one copy of each homologous chromosome from each parent, which combine to make a genetically unique diploid organism. Haploid cells, containing a single copy of each homologous chromosome, are found only within structures that give rise to gametes. All animals and most plants produce gametes called eggs and sperm

Species

-a group of organisms that can reproduce naturally with one another and create fertile offspring -groups that help us identify which organisms we are talking about

genetic disorder

-a health problem caused by one or more abnormalities in the genome -it can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality

Negative feedback

-a mechanism that reverses a deviation from the set point - maintains body parameters within their normal range -involvement within the maintenance of homeostasis - an act to oppose the stimulus, or cue, that triggers them -EX- if your body temperature is too high, a negative feedback loop will act to bring it back down towards the set point, or target value, of 98.6 ∘ F 98.6 ∘ F 98.

Genetic drift

-a process where populations evolve randomly and not through natural selection -the change in the frequency of an existing gene variant in a population due to random sampling of organisms. The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces -caused by a number of chance phenomena, such as differential number of offspring left by different members of a population so that certain genes increase or decrease in number over generations independent of selection -a mechanism of evolution in which allele frequencies of a population change over generations due to chance (sampling error) -occurs in all populations of non-infinite size, but its effects are strongest in small populations -also occurs when a portion of the population disperses to a new habitat or becomes separated by a physical barrier. This phenomenon occurs whenever a few individuals colonize an island from a population on the mainland

Fertilization

-a requirement for sexual reproduction -the union of two cells from different organisms and if those cells each contain one set of chromosomes, their union results in a cell with two sets of chromosomes

Stabilizing selection (y=ax^2+bx+c)

-a type of natural selection in which the population mean stabilizes on a particular non-extreme trait value -the mean of the trait remains similar over time but the standard deviation decreases -results in a decrease of a population 's genetic variance when natural selection favors an average phenotype and selects against extreme variations -examples of traits that resulted from stabilizing selection include human birth weight, number of offspring, camouflage coat color, and cactus spine density -tends to remove the more severe phenotypes, resulting in the reproductive success of the norm or average phenotypes. This means that most common phenotype in the population is selected for and continues to dominate in future generations

Environmental tolerance

-ability of an organism to endure unfavorable environmental conditions -reference for a limited range of conditions in which each species functions

Hybridization

-an animal carrying genes from two species -problem with hybrids arises from different genes whose products conflict during development or preproduction

Selection-drift balance

-an equilibrium in the number of deleterious alleles in a population that occurs when the rate at which deleterious alleles are created by mutation equals the rate at which deleterious alleles are eliminated by selection -occurs when multiple alleles are maintained in a population, which can result in their preservation over long evolutionary time periods

Thermal niche

-an example of some environmental condition like temperature and some measure of fitness performance -defined by the ability to raise body temperature above environmental temperature (defined as excess temperature or endothermy) and the ability to regulate the internal temperature within an optimal range of temperatures (defined as thermoregulation)

sexual reproduction

-an organism must spend much more time and energy than that required to build an offspring. The additional expense arises because sex requires a mate. Time and energy must be spent to find a suitable partner and convincing that individual to share the genetic benefits of sex -a type of reproduction that involves a complex life cycle in which a gamete with a single set of chromosomes combines with another to produce a zygote that develops into an organism composed of cells with two sets of chromosomes -the production of new organisms by the combination of genetic information of two individuals of different sexes -In most species the genetic information is carried on chromosomes in the nucleus of reproductive cells called gametes, which then fuse to form a diploid zygote -contains only half the alleles of each parent

Foraging

-behavior of moving from patch to patch in search of resources

bottleneck effect

-can occur in a single generation when a small number of individuals survive a natural disaster -a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violence or intentional culling, and human population planning

disruptive selection (y=ax^2+bx+c)

-changes in population genetics in which extreme values for a trait are favored over intermediate values -variance of the trait increases and the population is divided into two distinct groups -the standard deviation of the trait increases as individuals with the mean value disappear. This mode of selection will be opposed by random mating between members of the population when alleles recombine in the offspring to generate intermediate phenotypes -can produce new species when individuals choose to mate only with similar-looking individuals. This non-random mating prevents recombination from restoring intermediate phenotypes. Eventually, the population split into sub-populations that no longer interbreed

What isolates species?

-comes down to reproductive isolation between groups Two forms of reproductive isolation: Pre-zygotic: -use different habitats -active at different times -aren't sexually attracted -genital's don't match -gametes cannot fuse Post-zygotic: -hybrids die young -hybrids are sterile

dynamic equilibrium

-exists once a reversible reaction occurs -a state of balance between continuing processes

Courtship

-in animals, behavior that results in mating and eventual reproduction. Courtship may be rather simple, involving a small number of chemical, visual, or auditory stimuli; or it may be a highly complex series of acts by two or more individuals, using several modes of communication -can involve risky behaviors or expensive gifts, which signal the quality of the male's alleles to his desired mate. Males end up paying dearly to court females because eggs are a limited commodity

What causes genetic drift?

-independent assortment of alleles are random -random variation in survival -random variation in mating success -random variation in fecundity (number of offspring that you have) -any chance event that prevents you from passing on your alleles from one generation to the next is genetic drift

hermaphrodites

-invest time and energy in courtship and mating before each can produce and raise offspring -an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes

abiotic factors

-non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems -temperature, pressure, and pH are examples

Neutral allele

-one that confers no reproductive advantage or disadvantage -a form of a gene that when carried in an organism in no way alters the fitness of that individual to survive and reproduce

What is a species?

-organisms that can interbreed with each other and produce fertile offspring -a group of potentially interbreeding organisms

Acclimation

-physiological change in an individual stimulated by exposure to a different, often stressful, environment

Allopatry

-populations occur in different places -when two populations get separated in space and geographically isolated

Optimization

-refers to minimizing or maximizing a real function by systematically choosing the values of real or integer variables from a feasible set mathematically -widely applied in biological research

hidden genetic cost of sex

-sexual organisms must produce twice as many offspring to receive the same fitness as an asexual organism receives -adds to the obvious costs of courtship and mating

Niche

-something about an organism and its environment -the range of environmental conditions in which a genotype can persist

homeostasis

-staying the same -Maintaining homeostasis requires that the body continuously monitor its internal state -the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits

Evolution by natural selection

-stems from the observation that some individuals in a population are more likely to survive longer and have more offspring than others -this means that if an environment changes, the traits that enhance survival in that environment will also gradually change, or evolve EX-treefrogs are sometimes eaten by snakes and birds

thermoregulation

-the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different -a mechanism by which mammals maintain body temperature with tightly controlled self-regulation independent of external temperatures. Temperature regulation is a type of homeostasis and a means of preserving a stable internal temperature in order to survive

plasticity

-the adaptability of an organism to changes in its environment or differences between its various habitats -the capacity of an individual organism to alter its behavior, physiology/gene expression, and/or morphology (i.e., some aspect of its phenotype) in direct response to changing environmental conditions

Natural selection

-the differential survival and reproduction of individuals due to differences in phenotype -the process through which populations of living organisms adapt and change - It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations -Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population

founder effect

-the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population -occurs when a new colony is started by a few members of the original population -can increase the frequency of certain rare disorders, while other disease alleles characteristic of the parental population may disappear

Meiosis

-the nuclear division that forms haploid cells -process of meiosis can be broken into two parts: Meiosis I - a cycle through which a diploid cell divides to create two haploid cells, each receiving one of the homologous chromosomes. Meiosis II - a cycle through which the two haploid cells divide to form four haploid cells, which later develop into sperm or eggs.

Fitness

-the relative number of viable (survivable), fertile (reproducible) offspring -a measure of reproductive success (how many offspring an organism leaves in the next generation, relative to others in the group)

catabolism

-the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions -breaks down large molecules into smaller units -the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism

anabolism

-the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. - the building-up aspect of metabolism, whereas catabolism is the breaking-down aspect -the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism

energy budget

-the specification of the uptake of energy from the environment by an organism (feeding and digestion) and of the use of this energy for the various purposes: maintenance, development, growth and reproduction -accounts for the fraction of energy absorbed from food lost as heat through catabolism and transferred to tissues through anabolism

Gene pool

-the total genetic diversity found within a population or a species -the set of all genes, or genetic information, in any population, usually of a particular species -The set of all alleles at all loci is the full gene pool for the species. Over time, the size of a gene pool changes. The gene pool increases when a mutation changes a gene and the mutation survives. The gene pool decreases when an allele dies out

biomass

-the total mass of organisms in a given area or volume -plant or animal material used as fuel to produce electricity or heat

modes of selection

-there are three modes of selection: stabilizing selection, directional selection, and disruptive selection

Endotherm (warm-blooded animals)

-those that maintain a constant body temperature independent of the environment

directional selection (y=bx+c)

-when individuals with traits on one side of the mean in their population survive better or reproduce more than those on the other -a mode of negative natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype -it does the "heavy lifting" of evolution by tending to move the trait mean toward the optimum for the environment. It results in increased adaptedness of organisms -the mean phenotype shifts in a particular direction. For this process to work, the environment must change slowly enough for the population to persist. If the environment changes too quickly, no members of the population will be able to reproduce, leading to extinction

1. Natural Selection 2. Genetic Drift 3. Random mutation

1) -causes phenotypes to evolve in a particular direction -requires repeatable differences in reproductive success among genotypes -always causes adaption of a trait -the most important mechanism of evolution in a large population 2) -has a large effect on allele frequency in a small population -has a small effect on allele frequency in a large population -requires random difference in reproductive success among genotypes -causes reproductive isolation to evolve between geographically isolated subpopulations 3) -causes phenotypes to evolve in a random direction -creates a new allele in a population -requires repeatable differences in reproductive success among genotypes -sometimes causes adaptation of a trait -sometimes causes maladaptation of a trait

Genotype

1) of an organism is its complete set of genetic material. 2) the alleles or variants an individual carries in a particular gene or genetic location

1. True or False? An enzyme maintains a rigid structure while catalyzing a reaction. a. True b. False 2. Which type of chemical bond will stabilize an enzyme's structure the most? a. Hydrogen b. Covalent c. Ionic d. Metallic 3. Organisms such as the Antarctic fish can swim at extremely low temperatures. Which mechanism best describes how they do this? a. They modify their proteins to be more flexible. b. They modify their proteins to be more rigid. c. They do not use proteins. d. They warm their bodies through metabolism. e. They live in a frozen state. 4. Which type of organisms should evolve the most rigid enzymes? a. Desert organisms b. Nocturnal organisms c. Aquatic organisms d. Polar organisms

1. False 2. Covalent 3. They modify their proteins to be more flexible. 4. Desert organisms

Shrews use endothermy to elevate their body temperature. On cold nights, however, shrews will allow their bodies to cool and then rewarm in the morning. To study the cause of this phenomenon, researchers shaved some shrews and recorded their temperatures over a period of many days. They also recorded the temperatures of shrews that had not been shaved. The figure shows the mean body temperatures of two groups of shrews during the study: shaved shrews and unshaved shrews. 1. As a control, the unshaved shrews would have to be handled by researchers but would not have to see a razor. a. True b. False 2. All else being equal, a shaved shrew loses less heat by convection than an unshaved shrew. a. True b. False 3. After lowering its body temperature, a shaved shrew would lose less heat by convection. a. True b. False 4. To reduce the energetic cost of thermoregulation, a shrew could remain in its burrow instead of foraging on the surface; however, this behavior would impose an opportunity cost. a. True b. False 5. Given unlimited food, a shrew should continue to drop its temperature on cold nights. a. True b. False

1. False 2. False 3. True 4. True 5. False

A male animal has enough sperm to fertilize the eggs of many females. From a male's perspective, then, we can think of reproductive females as patches of resources to be located and exploited. The graph below shows how males of two species fertilize eggs during mating. Although the curves differ between species, both species mate for the same duration, indicated by the single arrow pointing to the x-axis. 1. The rate of fertilization increases with the time that a male spends mating. a. True b. False 2. This model depicts an opportunity cost of searching versus mating. a. True b. False 3. A male that mates for longer than the optimal time may miss an opportunity to mate with another female. a. True b. False 4. Species 1 more closely matched its mating time to the optimal mating time. a. True b. False 5. A male that mates for the optimal time will not fertilize all of the eggs carried by a female. a. True b. False

1. False 2. True 3. True 4. False 5. True

In certain populations, people grow to a much smaller size than people do in other populations. For example, African pygmies are essentially miniature humans, with all the same proportions of other Africans except for their short stature (Fig. 1). Researchers discovered that pygmies begin to reproduce at a younger age than humans of normal stature do. Prior to the reproduction, pygmies grow about as fast as people in other populations do. 1. African pygmies are likely to reproduce earlier because they lack sufficient food to continue growing. a. True b. False 2. Pygmies likely evolved because individuals who reproduced early in life were more fit than individuals who reproduced later in life. a. True b. False 3. African pygmies are likely to live in risky environments, where the probability of survival is low compared to other environments where humans live. a. True b. False 4. If a mutation occurred, causing the daughter of two pygmies to grow taller than usual, this daughter would likely reproduce at an even earlier age than her parents did. a. True b. False 5. If a pygmy were to mate with an African of normal size, the offspring would likely be intermediate in size. a. True b. False

1. False 2. True 3. True 4. False 5. True

Scientists believe that when a species adapts to high temperatures it loses its ability to function at low temperatures. To test this hypothesis, researchers took populations of bacteria growing for years at 37° C and let them evolve at 42° C for 100 days. The nice thing about bacteria is that you can freeze them today and defrost them years from now and they will start to grow. Therefore, the researchers could freeze some bacteria at the start of their experiment and then compare these genotypes to the ones left at the end of their experiment. 1. To replicate this experiment, researchers only needed one population of bacteria, because bacterial populations contain millions of individuals. a. True b. False 2. To control for stress, the researchers should have frozen some bacteria at the end of the experiment and defrosted these descendants along with their ancestors before comparing their thermal niches. a. True b. False 3. If adaptation occurred, genotypes remaining at the end of the experiment should have had more rigid enzymes than their ancestors had. a. True b. False 4. If adaptation occurred, genotypes remaining at the end of the experiment should outcompete their ancestors at 37°C and at 42°C. a. True b. False 5. Assuming that the ancestral populations and the evolved populations were compared under the same environmental conditions, any difference in fitness at 42C would more likely resulted from adaptation than plasticity. a. True b. False

1. False 2. True 3. True 4. False 5. True

1. Most organisms grow as much as possible throughout their lives. a. True b. False 2. All else being equal, an organism that grows more in a given period will reproduce less during that period. a. True b. False 3. An organism that invests more energy in reproduction will likely ______________. a. live longer b. die earlier c. be unaffected by this decision 4. An organism that invests energy primarily in growth, likely lives in a. an aquatic environment b. a terrestrial environment c. a safe environment d. a risky environment 5. The age at maturity is the age at which an organism ______________________. a. completes embryonic development b. starts to reproduce c. is killed or dies d. leaves its parents

1. False 2. True 3. die earlier 4. a safe environment 5. starts to reproduce

1. The range of environmental temperatures in which a genotype can persist is one aspect of its _________. a. habitat b. niche c. behavior d. phylogeny 2. The niche of a fish is defined by ______________. a. temperature b. salinity c. pH d. other species of fish e. All of the above 3. The thermal niche of a desert organism __________________. a. will differ from that of a polar organism. b. will include very low temperatures. c. will include the critical thermal maximum of a polar organism. d. is unlikely to include high temperatures. e. is unlikely to limit its distribution on Earth. 4. The fact that one can find fish in both tropical and polar waters implies that _______________. a. a single fish can swim in just about any body of water on Earth. b. tropical and polar waters provide similar selective environments. c. different species of fish have adapted to different environmental conditions. d. most fish migrate between tropical and polar waters. 5. Which is the best description of the niche of a salmon? a. the Columbia River b. salinities between 0 and 3000 ppm c. March through September d. All of the above are equally good descriptions of the niche.

1. Niche 2. All of the above 3. will differ from that of a polar organism. 4. different species of fish have adapted to different environmental conditions. 5. salinities between 0 and 3000 ppm

Populations of flies were maintained at controlled temperatures. Some populations were kept at 25°C, while others were kept at 16°C. The third set of populations were shifted between 16°C and 25°C every generation. In these populations, offspring were guaranteed to experience a different temperature than their parents. After 50 generations, genotypes from each population were raised at 16°C and 25°C. When these genotypes were adults, their ability to fly was tested at 16C and 25°C. The figure below shows the results of these measurements. Data are mean probabilities of flight at each test temperature. Left and right panels show data for flies that developed at 16°C and flies that developed at 25°C, respectively. The text next to each mean denotes the condition under which the population evolved (H = 25°C, C = 16°C, and F = fluctuating). 1. Flies from populations at fluctuating temperatures should have evolved the greatest capacity for acclimation. a. True b. False 2. Genotypes from populations at 16°C performed best when raised at 16°C and tested at 25°C. a. True b. False 3. Genotypes from all populations displayed the same degree of plasticity. a. True b. False 4. The sample size in this experiment is the number of flies in each treatment. a. True b. False 5. Flies would likely have benefitted less from acclimation if the temperature had changed several times per generation instead of once every generation. a. True b. False

1. True 2. False 3. False 4. False 5. True

When humans began hunting cheetahs, their population declined rapidly (see the photo). About 10,000 cheetahs remain in the wild, making them an endangered species. Researchers wonder whether the population has the genetic variation needed to recover and adapt to future changes in the environment. Researchers quantified the genetic variation in the population by identifying the alleles for 47 genes. For every gene, the population was homozygous for a single allele. From this sample, they concluded that virtually no genetic variation remains among cheetahs. 1. Prior to hunting, the population likely had more alleles for the 47 genes. a. True b. False 2. The loss of genetic variation likely stemmed from an increase in the mutation rate. a. True b. False 3. Following the decline of cheetahs, the population would more likely adapt to environmental change. a. True b. False 4. The population was more likely to experience genetic drift before hunting than it was after hunting. a. True b. False 5. If the population of cheetahs continues to decline, genetic drift would be more likely to eliminate new alleles resulting from mutation. a. True b. False

1. True 2. False 3. False 4. False 5. True

1. Genetic drift occurs whenever a random event causes a genotype to reproduce more than others in a population. a. True b. False 2. On average, genetic drift will increase the frequency of a deleterious allele. a. True b. False 3. If a population doubles in size, a deleterious allele should become less likely to drift to a higher frequency. a. True b. False 4. Genetic drift cannot occur in the same generation as natural selection. a. True b. False 5. Genetic drift cannot eliminate a beneficial allele from a population. a. True b. False

1. True 2. False 3. True 4. False 5. False

The figure shows the body temperature of a lizard during a clear day in June. Arrows indicate times when the lizard emerged from its burrow, reached the surface of the ground, and retreated into the burrow at the end of the day. 1. Between 7 and 8 am, the lizard was likely exposed to solar radiation. a. True b. False 2. Between 9 am and 7 pm, the lizard likely used endothermy to maintain a high, stable temperature. a. True b. False 3. Between 9 am and 5 pm, the lizard was likely moving repeatedly between sun and shade. a. True b. False 4. Between 9 am and 5 pm, the lizard spent energy to thermoregulate but avoided any risk of predation. a. True b. False 5. After 7 pm, you would expect the body temperature of this animal to decrease sharply. a. True b. False

1. True 2. False 3. True 4. False 5. True

Seven populations of salamanders in the genus Ensatina occur throughout the western edge of the United States (see figure). For years, these populations were considered separate species, because they look different from each other. However, biologists studying these populations discovered that most of these population interbreed to produce viable and fertile hybrids. The only two populations that cannot interbreed are the ones at the southern edge of the range, referred to as Ensantina klauberi and Ensatina eschscholtzii. 1. Ensantina klauberi and Ensatina eschscholtzii could be considered different morphological species. a. True b. False 2. Ensantina klauberi and Ensatinaesch scholtzii should be considered different biological species. a. True b. False 3. The genes of Ensatina eschscholtzii should be more similar to the genes of Ensatina xanthoptica than they are to the genes of Ensantina klauberi. a. True b. False 4. If biologists consider Ensantina klauberi and Ensatina eschscholtzii to be different species, they would likely argue that postzygotic isolating mechanisms had reinforced speciation. a. True b. False 5. If the population of Ensantina klauberi and the population of Ensatina eschscholtzii remain in contact, natural selection would likely favor a prezygotic isolating mechanism. a. True b. False

1. True 2. False 3. True 4. True 5. True

A researcher studied the relationship between the phenotypes of snakes and their fitness. First, he measured the color patterns and the escape behavior of hundreds of snakes. For color pattern, snakes were scored as being either checkered or striped (see photo). For escape behavior, snakes were chased by simulating a predator attack; some snakes moved in a straight line while fleeing, but others tended to turn frequently. After recording these phenotypes, the researcher released the snakes in their natural environment. A year later, he returned to see which snakes had survived. The survival of snakes was used as a proxy of fitness. The figure below shows the relationships between color pattern and relative fitness for snakes that flee straight and snakes that flee by turning. 1. A snake with stripes would be more likely to survive by fleeing predators in a straight line. a. True b. False 2. Regardless of escape behavior, the color pattern of snakes will be influenced by directional selection. a. True b. False 3. Over many generations, the population of snakes should evolve toward striped snakes that flee by turning or checkered snakes that flee straight. a. True b. False 4. The strength of selection for a color pattern is greater in snakes that flee by turning than in snakes that flee straight. a. True b. False 5. Although the researcher estimated fitness by survival, he could have also used another proxy for fitness, such as mating success. a. True b. False

1. True 2. True 3. False 4. True 5. True

In the fruit fly, Drosophila melanogaster, a phenotype known as barred eyes sometimes appears, in which the eyes are shaped like thin bars instead of being round. Additional crosses revealed that a dominant allele on the X chromosome causes barred eyes. Oddly, however, the allele arises only when two flies with normal eyes are crossed. In this case, fewer than 1% of the offspring will have barred eyes. Male offspring never develop barred eyes. Researchers hypothesized that the allele forms when the X chromosomes of a female cross over unequally during meiosis, leading to one long and one short chromosome. This allele lies at a locus directly next to a locus called B but on the opposite end of the chromosome from locus A. 1. If the researchers are correct, the X chromosomes likely cross over at the locus that controls normal or barred eyes. a. True b. False 2. After crossing over, both chromosomes will contain new alleles at the point of crossover. a. True b. False 3. If the chromosomes crossed over equally, the resulting gametes would likely have the same number of genes. a. True b. False 4. An allele at locus A is more likely than an allele at locus B to remain linked to the allele for barred eyes. a. True b. False 5. The allele at locus B is likely to be lethal when combined with the allele for barred eyes. a. True b. False 6. If the X chromosome crosses over with the Y chromosome, the resulting gametes are likely to generate healthy offspring. a. True b. False

1. True 2. True 3. True 4. False 5. False 6. False

1. Phenotypic plasticity occurs when one __________ produces multiple __________. a. allele / proteins b. protein / alleles c. genotype / phenotypes d. phenotype / genotypes 2. The primary cost of tanning is ______________________. a. the energy needed to produce melanin b. the time needed to lay in the sun c. the money needed to purchase sunblock d. All of the above are equally costly 3. Which of the following environmental factors can affect the phenotypes expressed by a genotype? a. Atmospheric oxygen b. Diet c. Solar radiation d. Humidity e. All of the above cause plasticity 4. All individuals of a species express the same degree of plasticity. a. True b. False 5. Plasticity is most adaptive when the environment changes __________ throughout an organism's life. a. rapidly and predictably b. slowly and predictably c. rapidly and unpredictably d. slowly and unpredictably

1. genotype / phenotypes 2. the energy needed to produce melanin 3. All of the above cause plasticity 4. False 5. slowly and predictably

1. The optimal strategy maximizes the ___________. a. benefit b. cost c. net benefit d. net cost 2. The net benefit equals the benefit divided by the cost. a. True b. False 3. When biologists use an optimality model to predict foraging behavior, they assume that animals behave in a way that a. maximizes energy gained over time. b. maximizes reproductive success over a lifetime. c. maximizes immediate reproductive success. d. maximizes the probability of survival. 4. If your professor in the video were behaving optimally, he should have opened a new bag of potato chips instead of eating crumbs from an old bag. a. True b. False 5. When modeling foraging behavior, biologists assume that food occurs only in ___________. a. kitchens b. soil c. oceans d. patches e. forests

1. net benefit 2. False 3. maximizes energy gained over time. 4. True 5. patches

1. Allopatry occurs when _________________. a. populations become separated geographically. b. populations exchange alleles by migration. c. populations become two separate species. d. populations go extinct. 2. Which of the following observations provides the best experimental evidence that populations diverge during allopatry? a. Hybrid offspring of cold-adapted and saline-adapted genotypes were more viable than purebred offspring. b. Hybrids of offspring cold-adapted and saline-adapted genotypes were less viable than purebred offspring. c. Exposure to cold enabled populations to evolve better performance at low temperatures. d. Exposure to salt enabled populations to evolve better performance at high salinity. 3. When populations become geographically separated for a period and then come back into contact, they __________ become different species. a. always b. sometimes c. never 4. Speciation occurs more often between allopatric populations than it does between sympatric populations. a. True b. False

1. populations become separated geographically 2. Hybrids of offspring cold-adapted and saline-adapted genotypes were less viable than purebred offspring. 3. sometimes 4. True

key point

Acclimation provides a benefit but also poses a potential cost.

key point

Adaption to abiotic conditions involves tradeoffs that limit the breadth of a niche. -These tradeoffs occur because we have the design enzymes of certain conditions that we see and if we had to see a wide range of conditions we would need multiple versions of the same enzymes to survive over that wide range.

Write a figure legend EX (see photo).

As the cost of thermoregulation increased, animals thermoregulated less accurately until they became thermos conformers or animals that can form their body temperature to the air temperature. -if writing scientific paper, you would want to specify the symbols (deviation).

What if animals must learn to catch food?

At first the rate of return would be really low and then it would start to go up. The slow period of time is the learning part.

key point

Both the direction and strength of natural selection varies greatly among traits and species. -When nature selects, it selects in very different ways, in very different species, and different traits. This tells us that the very act of nature itself leads to diversity because its a diverse process.

key point

Crossing over enables an organism to recombine alleles on the same chromosomes with alleles on a homologues chromosome. -so, you can take alleles that would never have been passed together because they are the same chromosome and potentially pass them on separately or together by crossing over

key point

Endotherms reduce, but rarely abandon, thermoregulation when the cost exceeds the benefit.

True or False? If the slope of the relationship between the phenotype and fitness is positive, natural selection would decrease the phenotype over generations.

False because a positive relationship will lead to an increase in the phenotype over generations, not a decrease. -a negative relationship would actually lead to a decrease in a phenotype over generations

True or False? Acclimation benefits an organism the most when the environment changes quickly and the phenotype changes slowly.

False, acclimation benefits the organism most when it can instantly change.

True or False? Acclimation involves a change in the genotype triggered by a change in the environment.

False, acclimation involves a change in the phenotype, it doesn't change at all in the genotype.

True or False? An endotherm is more likely than an ectotherm to have a narrow thermal niche.

False, endotherms can afford to have narrow thermal niches while ectotherms need a wider thermal niche because at night they have no solar radiation.

True or False? Genetic drift cannot eliminate beneficial alleles.

False, genetic drift can eliminate beneficial allele. -If population is small, genetic drift can be more powerful than natural selection and that beneficial allele could be lost before it has a chance to increase in frequency.

True or False? To maximize its energy gain, the bird should remain on one tree.

False, if the bird remains on one tree and it wants to maximize its energy gain, it wont be able to because food on that one tree will eventually run out and energy is burned as the bird stays in that one tree.

True or False? The longer the light remained lit, the greater the cost of thermoregulation.

False, if the light stays on for a long period of time for all that time the animal doesn't have to move, its sitting under that light heating up, and then when that light goes off, that's when it has to move, but if the light stays on for a short period of time, now the animal has to move every so many seconds to turn it back on so the longer the light stay lit, the shorter the cost and the shorter the light stays lit, the greater the cost of thermoregulation.

True or False? The sample size equals the number of fish in each stream.

False, in the experiment it is more focused on evolution and behavior not on the individual fish.

True or False? In this experiment, the cost of thermoregulation was a risk of predation.

False, in the experiment there was no predators, but if this were in nature and not in the experiment this would be true because an organism moving around would bring attention to itself.

True or False? A herring gull and a black-backed gull are different biological species.

False, they can be the same because gulls from different species can interbreed and eventually spread out their similar alleles. -they are members of the same biological species even though some members can't interbreed with each other

True or False? Stabilizing selection occurs more often than disruptive selection.

False, with current data, all three forms of selection can happen to some extent.

Write a figure legend EX (see image).

Figure 1. A decreased risk of death by moving guppies to a safe site, while the control guppies are in a risky site. The guppies that have been moved to the safe site, in the dark circles, they evolved the tendency to reproduce less. Guppies transplanted to safe sites evolved to reproduce less early in life compared to guppies that remained in control sites.

Write a figure legend (see photo).

Figure 1. In warmer vents, tube worms were more likely to have allele 90, which enhanced function at high temperatures.

How are these organisms thermoregulating? (see photo)

For the plant, it is the way it has its leaves positioned (straight up, parallelly) that helps it thermoregulate For the animal, it is the way it has its wings positioned (straight up) that helps it thermoregulate. Both are also exposed to air, so convection (like air blowing against an organism) could also be a reason.

key point

Genetic drift can eliminate beneficial alleles in small populations. -This creates a challenge for evolutionary biologist to think about more than just directed processes like selection which lead to greater and different types of biodiversity, but also random processes where we might expect something to evolve but doesn't because if mutation comes along it could be lost by drift

What is the appropriate control for a treatment in which one shaves a shrew? (see photo for reference)

Handling the shrew for the same amount of time because the stress of shaving it is something that might change the shrews physiology and effect the ability to thermoregulate.

Write a figure legend EX. (see photo) -explain what you see -write a sentence or two that describes the results you see in the figure, keeping in mind the treatments shown in figure -it should be accurate, it should convey the result of the study or pattern that you want readers to see, and it should give any information like symbols that are necessary for interpreting the graph

In constant environments, the frequency of sex in rotifers evolved to lower levels. In the figure, closed triangle represents heterogenous, closed circle represents homogenous high-quality food, and open circle represents homogenous low-quality food. -If graph has bars on circle (standard deviation) or the stars (low P value), you would have to specify what it represents.

key point

Natural selection not only changes mean phenotypes but also increases or decreases deviations from mean phenotypes. -in other words, it could cause disruptive or stabilizing selection and so now we can go out and look at data of nature to figure out which of these types of selection is the most common

key point

Optimality models help biologists to understand phenotypes.

Key point

Organisms abandon homeostasis when the cost exceeds the benefit. -this is because they thermoregulated when the light stayed on for a long period of time, but if the light was turning off after a short period of time and the organism had to move back and forth over and over again, they would just give up at some point.

key point

Organisms have a limited capacity to accumulate to environmental change.

key point

Organisms use energy to enhance lifetime reproduction, not current reproduction.

Write a figure legend brief EX (see photo). -write a description based on what you see on the plots shown in the photo

Populations in this experiment drifted over the allele frequencies and populations in experiment drifted over generations. However, small populations exhibited greater fluctuations in allele frequencies than large populations. -you want to be more specific than this brief example

key point

Sex creates genetic variation among offspring, enabling populations to adapt to environmental change faster. -in rapidly changing environments, this is what gives sexual organisms an edge over asexual ones

Which type of selection is most common?

Stabilizing or directional selection could be the most common, where either natural selection weeds out the extremes so that it favors a particular value or an extreme value whether small or big.

True or False? If each tree contained fewer insects, the bird should spend more time feeding on a tree before searching for a new tree.

True, a tree with fewer insects is considered a poor patch, where you deplete the energy of the patch much faster.

True or False? Two species mate but their offspring die before reaching adulthood. A more efficient way to prevent interbreeding would be to have incompatible genitals.

True, because having incompatible genital's will prevent two organisms from interbreeding.

True or False? On cloudy days, neither species thermoregulated, likely because solar radiation was absent.

True, both species don't thermoregulate on cloudy days because they can't thermoregulate without the presence of solar radiation.

True or False? If the parameter for the squared term is negative, natural selection will likely stabilize the phenotype at an intermediate value.

True, if selection is negative, the selection would more likely stabilize. -It is likely to stabilize because it depends on how large the parameter is for the squared term, the "a" from y=ax^2+bx+c. Because if it isn't large enough, what might happen is that it might slow it down, but never actually bring it all the way back down again or it might not be large enough to keep it from increasing all together, it might just be like a weak increase, but still won't come down again

True or False? Genetic drift should affect have a bigger effect on the evolution of small populations.

True, if the probability of a neutral allele spreading by drift is 1/2n, the smaller n gets the larger that ratio 1/2 gets and so this is going to be true for detrimental alleles or beneficial alleles if its true for neutral alleles. --Small populations are gonna promote genetic drift.

True or False? As the risk of death increases, an organism should reproduce earlier and more often.

True, if you're likely to die anyway in the near future, you might as well waste your energy in reproducing in order to create offspring and therefore increase your fitness.

True or False? Directional selection is more likely to be weak than strong.

True, it comes down to the logic that there's way more cases of weak or very low values of "b" directional selection than there are cases of strong directional selection. Therefore, when it comes to directional selection, nature tends to select very weakly.

True or False? The enzymes of animals in old vents should be more flexible than those of animals in young vents.

True, it should be more flexible because that it what allows them to have the flexibility despite being cold (old vents) to actually change shape and cause that reaction to happen.

True or False? When an organism moves from sun to shade, it reduces heating by conduction.

True, not only does it reduces heat by conduction (surface) but also by radiation (suns rays), both factors come into place when an organism moves from sun to shade.

True or False? In a rapidly changing environment, a population would likely benefit more from sexual reproduction than from asexual reproduction.

True, sex allows a population to adapt quickly and that would be good because we need a lot of genetic variation.

True or False? Natural selection will likely eliminate deleterious alleles more quickly with sexual reproduction than with asexual reproduction.

True, sex works in both directions, it helps to speed the evolution the spread of beneficial alleles, and it helps speed the disappearance of deleterious alleles.

True or False? Given unlimited food, shrews should enter torpor on cold nights.

True, shrews would eat and then burn the energy even if it gets cold at night.

True or False? If a parent passes one copy of each chromosome to offspring, alleles on the same chromosome would be inherited together.

True, the alleles in the same chromosome would be inherited together and this is where the violation of Mendel's law come in because these two alleles aren't passed down independently.

True or False? Given a limited supply of energy, fish acclimated to a high temperature should outperform fish acclimated to a low temperature, when tested at high temperatures.

True, the fish acclimated at high temperature outperforms those in low temperature when tested at high temperatures because the fish at high temperatures are used to the high temperatures.

True or False? The observed increase in CTmax likely reflects greater swimming performance at 4°C.

True, the fish only have been at 4°C.

True or False? If energy gain remained constant over time, the bird would maximize energy gain by staying on the tree forever.

True, the patch remains constant, so the slope would just keep increasing by staying on the tree (even though this is an unrealistic example).

True or False? If Mendel had compared traits controlled by genes on the same chromosome, his results would not have matched the predictions of his model.

True, when there is no linkage and there's things on all separate chromosomes, you expect more than 4 outcomes on a punnet square model (photo), but when you have linkage, it cuts out some of the possibilities (unless you have crossing over, but possibility is low).

key point

Two organisms belong to the same species if their alleles can end up in the same organism.

Phenotype

all the observable characteristics of an organism that result from the interaction of its genotype (total genetic inheritance) with the environment EX of observable characteristics: behavior, biochemical properties, color, shape, and size

Haploid or diploid

cells containing one or two sets of chromosomes

ploidy level

number of sets of chromosomes in a cell

alleles

one of two, or more, forms of a given gene variant EX: the ABO blood grouping is controlled by the ABO gene, which has six common alleles