Biol 301 1nd Edition Lecture 9 Outline of Last Lecture I. Microevolution/ macroevolutionII. Hardy- Weinberg PrincipleIII. VariationOutline of Current Lecture II. AdaptationsIII. Migration/ Storage/ DormancyIV. Variation in foodV. Life History TraitsCurrent LectureAdaptations- Many organisms can adjust their physiology to maintain activity across different environmental temperatures.- Many animals respond to temperature by moving to microhabitats.- Microhabitats: locations within a habitat that differ in environmental conditions from the rest of the habitats.- Most animals can move to different microhabitats where water is more available.- Plants cannot move, and exhibit numerous adaptations.- In response to scarce water, many plants will close their stomata, or adjust relative allocations of energy and material to grow longer roots.- A common strategy is to change the osmotic potential of body fluids by synthesizing large quantities of organic solutes.Migration, storage, and dormancy- Sometimes, adverse conditions are so severe that individuals cannot acclimate, or the changes required would not be worth the cost.- Migration is the seasonal movement of animals from one region to another.- The decision to migrate is a plastic behavior in response to changing environmental conditions, such as temperature or food suppliesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- When resources are limited and migration is not possible, storage of resources can be an adaptive strategy.- Animals accumulate fat or cache food supplies as a reserve of energy for periods of harsh weather when food is inaccessible.- Plants may store nutrients and energy in roots.- Dormancy: a condition in which organisms dramatically reduce their metabolic processes. Four types of dormancy are:o Diapause: involves a partial or complete physiological shutdown in response to unfavorable conditions; common in insects.o Hibernation: individuals reduce the energetic costs of being active by lowering heart rate and decreasing body temperatures; common in mammals.o Torpor: a brief period of dormancy in which individuals reduce activity and body temperature; common in birds and mammals.o Aestivation: the shutting down of metabolic processes during the summer in response to hot or dry conditions. Well-known examples include snails, desert tortoises, and crocodiles.- Some terrestrial animals survive cold weather on land by producing antifreeze chemicals that control the formation of ice crystals.- Some animals burrow in places where temperatures are warmer, but body temperatures can still go below freezing.- Many amphibian species can freeze solid underground in a state that requires little metabolic activity.- They survive by producing antifreeze compounds and by forming ice crystals between cells rather than within them.Variation in food- Foraging is a plastic behavior because different feeding strategies represent different behavioral phenotypes.- Since resources vary in space and time, no single foraging strategy can maximize an animal’s fitness.- Animals must determine where to forage, how long to feed in a certain patch of habitat, andwhich types of food to eat.- Animals have four responses to food variation in space and time, including central place foraging, risk-sensitive foraging, optimal diet composition, and diet mixing.- Central place foraging: foraging behavior in which acquired food is brought to a central place (e.g., a nest with young birds).- As an individual forages farther from the central place, it finds greater amounts of resources,but this increases energy costs and the amount of food the individual must bring back.- As an individual feeds and collects prey, it becomes increasingly difficult to hold or consume the next prey item (i.e., there are diminishing benefits over time).- Foraging decisions depend on the time needed to travel round-trip to site with resources (i.e., traveling time) and the time spent obtaining food at a site (i.e., searching time).- At sites farther away, birds should spend more time searching for food and bring back more food to offset the extra travel time.- Risk-sensitive foraging: foraging behavior that is influence by the presence of predators.- Most animals do not consume a single food item, and base their diet decisions on handling time in addition to the energetic and nutritional value of various resources.- Handling time: the amount of time that a predator takes to consume a captured prey.- The energy benefit of a resource item divided by the handling time is the amount of energy gained per unit time.- A predator should always eat the prey species that provides the highest amount of energy gained per unit time.- If the highest energy prey is rare, the animal should include less profitable items in its diet.- Some foragers consume a varied diet because one type of food might not provide all of the necessary nutrients.Life History Traits- Life history: the schedule of an organism’s growth, development, reproduction, and survival;represents an allocation of limited time and resources to achieve maximum reproductive success.- Fecundity: the number of offspring produced by an organism per reproductive episode.- Parity: the number of reproductive episodes an organism experiences- Parental investment: the time and energy given to an offspring by its parents.- Longevity (life expectancy): the life span of an organism.- Life history traits often vary consistently with life form, habitat, or environmental conditions (e.g., seed size is generally larger for larger plants).- Variation in one life history trait is often correlated with variation in other life history traits (e.g., the number of offspring is negatively correlated with the number of offspring).- “Slow” life historyo Long time to sexual maturityo Long life spanso Low numbers of offspringo High parental investmento Examples: elephants, oak trees- “Fast” life historyo Short time to sexual maturityo Short life spanso High numbers of offspringo Little parental investmento Examples: fruit flies, weeds- J. Philip Grime proposed that plant life history depends on stress, competition, and the frequency of disturbances.- Plants functioning at the extremes of these environmental axes could be categorized as stress