Represent each of the following combinations of units in the correct SI form: (a) kN>ms, (b) Mg>mN, and (c) MN>(kg ms).
Biology: April 11-15 The Biosphere The Climate and Ecosystems: • Different ecosystems result in the interaction of various features of the earth o Solar heat variations result into seasonal changes § Earth is tilted at a 23.5 degree angle § Temperature decreases as you move up into the atmosphere or away from the equator o Atmosphere air circulations results in various things such as ocean currents (in combination with location of land masses) § Three cells of circulation in each hemisphere o Deserts form in the interior of large continents § Rain shadow effect- dry air creates desert conditions • Biomes o Major community of organisms that have a characteristic appearance and are distributed over a wide land area; defined by regional variations in climate o Temperature and precipitation differences o Distinct vegetation differences o Predictors of biome distribution: o Major Biomes: § Tropical rain forest § Savannah § Desert § Temperate grassland (prairies) § Temperate deciduous forest § Temperate evergreen forest § Taiga (boreal forest) § Tundra (contains permafrost) o Marine Ecosystems: § Neritic zone- less than 300m below the surface along coasts § Intertidal region- exposed to air when tides recede § Pelagic zone (oceanic)- open sea § Benthic zone (aphotic)- depths below 1000m; abyss; volcanic vents is a popular location for life o Freshwater Ecosystems: § Lakes and Ponds § Photic zone- area of photosynthetic organisms § Littoral zone- shallow area along shore § Limnetic zone- surface water away from shore § Profundal zone- area below light penetration § Thermocline- where higher water is warmer than lower water which drops and mixes together in colder temperatures § Eutrophic- rich in nutrients and organic matter § Oligotrophic- poor in nutrients and organic matter; often deeper; very susceptible to chemical pollutants o Streams and Rivers § Temperature, rate of flow, oxygen content, sediment o Wetlands § Diverse ecosystem o Estuaries (rivers join oceans) § Brackish (partly saline) Pollution: (effects climate, and therefore species) • Human causes o Agriculture, ex. DDT • Acid rain • Ozone hole o Stratospheric ozone protects life from ultraviolet rays o Depletion majorly due to CFC’s • Carbon dioxide o Traps heat in the atmosphere which leads to warming o Greenhouse effect Animal Behavior • Behavior- how an organism responds to stimuli • Proximate causation- how it works • Ultimate causation- evolution of the behavior • Nature vs. Nurture- instinct or learned behavior Innate Behaviors: • Early ethologists believed behavior was mainly innate • Fixed action pattern- stereotypical behaviors which are species specific o Repeated again and again o Triggered by sign stimulus • Super normal stimuli o Ex. aggressive behavior in sticklebacks- aggressive behavior to anything that looks like other males (red bellies) • Some behaviors are heritable due to genetics o Ex. twin studies o Single gene effects Learning: • Non-associative learning- does not form an association between response to stimuli o Habituation- decrease in response to repeated action due to no positive or negative consequences o Sensitization- increase response to a particular stimulus, ex. PTSD • Associative learning- forms a connection between a stimuli and response o Classical conditioning- parried presentation of two stimuli creates an association, ex. Pavlovian conditioning (Pavlov’s dogs) o Operant conditioning- animal learns to associate a behavior with a positive or negative reward, ex. trial and error learning o Mimicry is possible due to associative learning- species learn that certain species are dangerous with certain physical characteristics and therefore will leave species with those characteristics alone § Mullerian mimicry- all toxic species honestly share similar characteristics § Batesian mimicry of a butterfly where a toxic and nontoxic species look the same o Instinct and learning- animals have predispositions to forming certain associations § Learning preparedness- learning influences by selection/ecological factors o Spatial learning- ex. scrub jays cache food; remember where they put it and prevent other birds from stealing Development of Behavior: • Parent-offspring interactions o Imprinting- social attachment to individuals (usually during sensitive/critical period) o Filial imprinting- social attachment with parent and offspring • Genetic templates- form a connection between instinct and learning • Complex learning- ex. birdsong will develop over time • Animal cognition- do various animals think o Problem solving of certain animals can be very interesting § Ex. sea otters who drop their rocks will swim down to find them § Ex. chimpanzees will pile boxes to reach something • Orientation and Migration o Taxis- movement towards or away from a given stimulus, ex. moths to light o Kineses- increase in activity level in response to increased stimulus levels o Migrations- long-range, two-way movements § Navigation § Orientation- ability to follow a bearing, (magnetic field, celestial cues) • Courtship o Stimulus-response chain- behavior of one individual leads to the behavior of another § Signals are often species-specific o Pheromones- chemical messages between individuals, often used for sexual attractants o Acoustic signals- ex. grasshoppers o Level of specificity relates to the function of the song • Communication o Modes include: visual, sound, smell, pheromones, etc. o Chemical communication- alarm and trail pheromones o Social groups can increase chance of survival or lower one while it heightens others • Behavior Ecology - the study of how natural selection shapes behavior o Adaptive significant/survival value is examined to understand the level of fitness o Trade-offs with other selective pressures, such as mating o Optimal foraging theory- maximize net energy to intake efficiency o Territoriality- maintain exclusive use of an area with specific resources o Mate choice- when mating is not random o Parental investment- usually higher in females § Offspring needs: altricial- extensive and prolonged care; precocial- require little care o Bateman’s Principle: male make many large gametes and females make few large gametes (and bear resource cost), which means females are resource limited and males are mate limited o Sexual dimorphism- differences in characteristics between males and females besides the genitals o Monogamy- mate exclusively with one individual for a season or for life o Polygamy- (usually) males that mate with multiple females • Sexual Selection o When individuals compete for mating opportunities § Intrasexual selection- usually males competing for opportunity to mate with females; sperm competition (and adaptation, ex. promiscuous primate species have faster sperm than monogamous species); mate guarding § Intersexual selection- direct and indirect benefits • Handicap-hypothesis- only genetically superior males can survive with a handicap • Sensory exploitation- evolution of an attractive signal in males • Extra-pair copulations- may be very pervasive (males benefit by increased success and females benefit by increased rearing assistance § Leads to the evolution of secondary sexual characteristics § Trade-offs: exposure to predators, balancing the cost of breeding with survival, time