Midterm 1

• What are the levels of biological or ecological organization?

  Organism, population, community, ecosystem
• What types of research approaches do ecologists, evolutionary biologists, and behavioral biologists employ? What makes them different approaches, why is this important, and how are they useful?

  Mathematical Models: Simplify complex systems, Identify key elements and processes to be measured in nature, Generate hypotheses about an ecological system

  Observational Study: Measure data from real world, uncontrolled, environments

  Experiments: In experiments, one or a small number of variables are manipulated independently of others to reveal their particular effect
• What adaptations do animals have to avoid being eaten?

  Camouflage, mimicry, warning coloration, spines, toxins, speed, and defensive behaviors.
• How can predators affect prey individuals, populations, and communities, even if they do not kill the prey?

  Predators cause local populations to move farther and faster when present out of fear
• What are the different types of photosynthesis used by plants, and how are they adaptations to their environment?

  C3: Cool / Wet environments

  C4: Warm / Dry environments; minimize photorespiration by separating initial CO2 fixation and the Calvin cycle in space, performing these steps in different cell types

  CAM: Water stressed environments; minimize photorespiration and save water by separating initial CO2 fixation and the Calvin cycle in time, between night and day
• What is meant be the term ‘tradeoff’ as applied to adaptations, and what types of tradeoffs are exhibited in the evolution of photosynthetic pathways?

  Tradeoff refers to the concept of giving up one trait or characteristic in order to gain another. In the evolution of photosynthetic pathways, tradeoffs can be seen in the balance between efficiency and resource allocation, such as the tradeoff between maximizing energy capture and minimizing water loss.
• Describe adaptions fish have to different types of physical environments

  Freshwater: Eliminate excess water through urine, add solutes to bloodstream using gill cells to actively transport solutes from water to body, and kidneys remove ions from urine.

  Saltwater: Drink large amounts of saltwater and release small amounts of urine to replace water loss, excess solutes re actively excreted out of the body through kidneys and gills.
• What physical factors in the environment limit the distributions of species?

  Temperature, precipitation, nutrients, and soil type.
• What factors determine the distributions within fields or forests?

  Temperature, nutrients, and moisture
• What factors determine the distributions across continents?

  Physical barriers like oceans, mountains, etc
• What are similarities and differences between physical factors important to species distributions in terrestrial and aquatic environments?

  Similarities: Nutrients, temperature, soil

  Differences: Water flow, salinity, light penetration
• What are the key elements of the carbon cycle?

  Photosynthesis, respiration, decomposition, and combustion.

  Atmosphere, Oceans, Primary Production, Geosphere
• How does the carbon cycle relate to global warming?

  Warming increases atmospheric carbon released by soil but decreases atmospheric carbon because plants are more productive
• How have humans influenced the carbon cycle?

  Burning fossil fuels, deforestation, and land use changes add 40 billion tons per year disrupting the balance.
• What approaches are there to reducing human carbon influence?

  Stabilization wedges: small changes that add up like eliminating deforestation and increase coal power output efficiency
• What have been ecological effects of global warming?

  Plant and animal physiology and adaptation, Species distributions, Timing of seasonal events, Species extinctions
• What are some possible negative effects of ecological changes caused by global warming?

  Loss of biodiversity, increased frequency and intensity of natural disasters, disruption of ecosystems and food chains, rising sea levels, and loss of habitats.
• What factors determine a biome?

  Dominant plant form, temperature, soil type, and precipitation
• Temperate forest: deciduous trees, moderate to high diversity, fertile soils, seasonal moderate temperature, and constant high rainfall.
• Temperate grassland: fertile soils, high diversity of non-grass plants, fire important, seasonal moderate temperature, and seasonal moderate rainfall.
• Desert: infertile / fragile soils, plants adapted to drought, constant moderate temperature, and seasonal / constant low rainfall.
• Tundra: tree-less, nutrient poor, permafrost soils, seasonal low temperature, and constant low rainfall.
• Tropical rainforest: incredibly diverse, nutrient poor soils, highly productive, constant high temperature, and constant high rainfall.
• What conditions are needed for natural selection to occur, and how are these conditions evident in studies of the medium ground finch?

  Variation, heredity, reproductive success, and nonrandom survival and reproduction. In the medium ground finch, these conditions are evident through the variation in beak size and shape, the hereditary transmission of these traits, and the differential survival and reproduction of finches with different beak traits depending on the availability of food resources.
• What are life history characteristics?

  Traits and patterns of an organism's life cycle, including age at maturity, reproductive output, and lifespan.
• Tradeoffs in Life History Characteristics: Age at First Reproduction

  Benefits: Earlier reproduction causes higher population growth rates

  Costs: Lower survivorship of parents
• Tradeoffs in Life History Characteristics: Reproductive Effort

  Benefits: More effort leads to more offspring and higher population growth rates

  Costs: Lower survivorship of parent and offspring
• Tradeoffs in Life History Characteristics: Annual or Perennial

  Annual: Produce many seeds, but must get established

  Perennial: Established, but must survive winter and can't allocate as much to seed production
• What are the costs of sexual reproduction?

  Maintaining gonads, only half of genes are passed to offspring, and mating behavior
• Frequency-dependent: fitness is dependent upon the frequency of a trait in a population; ex: scale eating fish
• Stabilizing: individuals with moderate or average phenotypes are more fit; ex: birth weight
• Directional: a single phenotype is favored causing the allele frequency to continuously shift in one direction; ex: ground finch and increasebill size in response to seed hardness
• Disruptive: actively selects against the moderate traits in a population, favoring extremes; ex: finches with beaks for soft seeds and hard seeds (no medium sized beaks)
• How can altruism be explained among closely related animals?

  Kin selection / indirect fitness
• How can altruism be explained among unrelated animals?

  Reciprocal altruism: altruism now in expectation of altruism by other individuals in the future
• Inclusive fitness: the fitness of an individual plus the fitness of its relatives