Download BIOL 2003 UMN Exam 3: Ecology Learning Objectives, Questions and Answers and more Exams Biology in PDF only on Docsity!
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Define the science of ecology. - correct answer ✅Ecology is the study of interactions between organisms, and between organisms and their environment. Identify the levels in the "molecules-to-ecosystems" biological hierarchy that the science of ecology generally covers (small to large) - correct answer ✅organismal, population, community, and ecosystems Discuss how there are connections between ecology and the following sub-disciplines within biology: 1) evolution, 2) cell biology, 3) genetics. - correct answer ✅1) There is a connection between ecology and evolution as we can see how interactions between organisms and their environment affected evolutionary decisions. Many interactions between organisms and their environment directly affect evolutionary factors such as genetic drift and population isolation.
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- There is a connection between ecology and cell biology as many interactions between organisms can directly affect cellular interactions and cause consequences such as cell death, etc.
- Interactions between organisms affect genetics through lineages and can lead to speciation etc. abiotic and biotic environments - correct answer ✅Biotic: interactions between organisms Abiotic: interactions between organisms and nonliving environment three general features of the Earth that influence the distribution of ecosystems, communities, and populations, and discuss how each of these features has this effect. - correct answer ✅Competitors to organisms: can lead to an organism not being successful in a certain ecosystem. This mostly is natural enemies, or other organisms whose presence could lead to the death of other organisms.
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equatorial rain forests. The cold, dry air above flows towards the poles and falls back down to the earth, which creates areas of high pressure and deserts/arid landscapes. Describe, in general, how ocean currents can affect the types of terrestrial ecological communities found in a specific area. - correct answer ✅Wind creates ocean currents which run clockwise between continents in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. They can bring warm or cool water to different areas and encourage warmer or cooler climates for terrestrial communities. Discuss two general effects topography can have on the types of terrestrial ecological communities found in a specific area. - correct answer ✅Adiabatic cooling: increasing elevation means decreasing air pressure, which means temperature decreases as well. This can lead to only certain types of communities being able to live in the cooler higher climates.
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Rain shadow: warm moist air reaches the windward side of a mountain and flows upward. It cools and releases precipitation. Dry air descends down the leeward side, producing an area where precipitation is a lot less Explain what causes seasons on Earth. Discuss how seasonality can affect the types of species and communities found at a specific location on Earth. - correct answer ✅Seasons on earth are caused by the rotation of the earth on its axis and its revolution around the sun. As the earth revolves, it receives more direct sunlight on different parts of the planet depending on where it is in the revolution. This affects the amount of sunlight and therefore if it is summer or winter. This can affect communities found at the equator as they receive the most amount of sunlight regardless of the position in the revolution. High temperatures can also be harmful for organisms like algae and coral. High temperature can also cause fires and affect terrestrial organisms. Or, further from the equator, plants whose cells rupture during freezing temperatures will be less common in colder regions.
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Two biomes found in Minnesota: Temperate grassland, temperate deciduous forest Biome not found in MN: Hot desert Define physiological ecology. Provide three examples of research questions a physiological ecologist might ask. - correct answer ✅Physiological ecology is the study of how organisms physiologically interact and adapt to their environment, and how the environment impacts species distribution.
- How does a special organism withstand intense heat and why did it become that way?
- What caused the speciation of two physically distant populations?
- Why does a specific organism use anaerobic respiration and why is it adapted to do so? Provide examples of two different traits found in animals or plants that are likely physiological
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adaptations to the abiotic environment. Discuss how whether these traits are indeed adaptations could be tested. - correct answer ✅1. Traits such as white fur for individuals that live in cold snowy climates. This could be tested by finding the last common ancestor of a high-fat organism with a distant relative that is not adapted to build a lot of fat and comparing. Traits are considered adaptive when they are heritable, variable, and increase fitness Discuss the types of research questions asked within the discipline of behavioral ecology. - correct answer ✅Behavioral ecology seeks to focus on how the behavior of individual organisms affect their survival and fitness. This additionally affects population density of the species, leading researchers to ask questions such as what is the cause of a domination of a certain species. Discuss the evidence for the genetic basis of behaviors (necessary if behaviors are adaptations). - correct answer ✅In 1964 W.C. Rothenbuhler found that one gene controlled cell uncapping and another gene
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correct answer ✅Kin selection is an altruistic behavior where an individual will sacrifice their own fitness for a genetically related individual in order to pass on their genes. This increases indirect fitness even though it decreases direct fitness. Explain how "Hamilton's rule" can provide a basis for understanding the conditions under which behavior that superficially appears altruistic can evolve. - correct answer ✅Altruistic gene is favored by natural selection when: rB>C (r>C/B) r= coefficient of relatedness of donor to recipient B= benefit received by recipient of altruism C= cost incurred by donor Explain the action of reciprocal altruism, and how it differs from the action of kin selection. - correct answer ✅"You scratch my back I scratch yours" Different from kin selection because it offers a return benefit other than a boost in indirect fitness.
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Differentiate between asexual reproduction and sexual reproduction. - correct answer ✅Asexual reproductin: mitosis, splitting into two identical organisms Sexual reproduction: combination of gametes Discuss the general costs associated with sexual reproduction, especially the cost of meiosis and the cost of producing males. Based on these costs, summarize why the trait of sexual reproduction is challenging for evolutionary biology to explain as an adaptation. - correct answer ✅Meiosis in sexual reproduction means that there will be greater diversity in the population. Two types of gametes (sperm and eggs) must be made (often in large numbers), males and females require specialized body parts to mate with each other, and the two sexes must be able to find each otherCost of producing males in sexual reproduction is that males do not directly produce offspring, as females are required for this. So an overproduction of males would lead to population decrease likely Costs of sexual reproduction:
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assortment across many generations. As a result, some offspring carry combinations of alleles that promote survival and reproduction, whereas other offspring may carry less favorable combinations. Paland and Lynch found that sexual reproduction allowed for the reassortment of beneficial and detrimental alleles, making it easier for sexually reproducing populations to eliminate those mutations that are moderately detrimental. Explain the operation of sexual selection. Discuss how Bateman's 1948 data relates to the operation of sexual selection. - correct answer ✅Individuals with certain traits are more likely to successfully reproduce than other individuals, often affects males more than females. Bateman's principle states that gender for which reproductive costs are highest will have more discrimination in their mating choice
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Define anisogamy - correct answer ✅sexual reproduction by the fusion of dissimilar gametes discuss two hypotheses for why almost all sexually reproducing species have only two sexes, and explain how anisogamy is the basis for sexual selection. - correct answer ✅Males produce smaller gametes (microgametes) than females (macrogametes), meaning they can produce more gametes as they are cheaper to produce. This is basis for two genders, for example if there were multiple microgametes, they could fuse together but would have no nutrients for zygotes to grow. Intersexual selection - correct answer ✅(mate choice): usually females, choose mates from individuals of other sex based on desirable characteristics, often results in showy characteristics of males, also cryptic female choice (genetically related sperm less effective)
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cycle, mate-guarding hypothesis (males defend mate from other males), male-assistance hypothesis (males help rear young), female-enforced monogamy hypothesis (females stop male partners from being polygynous) Polyandry: - correct answer ✅One female mates with several males, rarer than polygyny. When there is a relatively high amount of food in the ecosystem and food is not a limiting factor, then the only limiting factor during the reproductive season could be finding as many mates as possible for a female. Also seen when egg predation is high, and males are needed to guard nests Define the term population - correct answer ✅A group of interbreeding individuals of the same species occupying the same area at the same time
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Discuss the concept of population dispersion - correct answer ✅Dispersion measures how clustered together or spread out a population is 3 kinds of basic dispersion Identify three general patterns of population dispersion and discuss factors that can lead to each pattern. - correct answer ✅Clumped dispersion: most common form of spacing as resources in nature are clustered (uneven distribution of resource) Uniform dispersion: even distribution of individuals, may be result of competition or social interactions (trees in forest for example) Random dispersion: least common form of spacing, probability of finding individual at any point in the area is equal Explain what the discipline of demography studies. - correct answer ✅Study of birth rates, death rates, age distributions, and sizes of populations.
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Explain what information a survivorship curve provides and discuss how survivorship curves are constructed - correct answer ✅Survivorship curve is a plot of numbers of surviving individuals for each age class in a population. Constructed to reveal unexpected changes in survivorship due to pressures such as human influence and predation, as well as provide information about survival patterns of species. Utilize log scales often to plot a wide range of pop sizes. Survivorship curve types - correct answer ✅Type I survivorship curve: most individuals die late in life Type II survivorship curve: uniform rate of decline Type III survivorship curve: most individuals die early in life Discuss the use of the net reproductive rate (R0) in understanding the growth characteristics of a population. -
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correct answer ✅R0 is the net reproductive rate, which is the sum of the number of offspring born to all females of all ages in one generation (mean period between birth of females and time birth of offspring). This value can be used to predict the changes in population growth by using current population and R to predict the population size of the next generation. A population will grow if R0>1, will shrink if R0<1, and will remain steady if R0= Lambda (finite rate of increase) - correct answer ✅ratio of population size from one year to the next Discuss what the instantaneous per capita growth rate (r) of a population is - correct answer ✅Little r is the per capita growth rate, or basically the amount of births minus deaths in a population. When r<0 the pop decreases, when r> the pop increases, when r=0 the population is at equilibrium (called zero population growth)
