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Ecology Midterm 1
| Question | Answer |
|---|---|
| Ecology | Scientific Study of Interactions between organisms and their environment |
| population | group of individuals of a single species that live in a particular area and interact with one another |
| community | association of interacting pops of different species that live in the same area at the same time |
| ecosystem | collection of communities of organisms plus the physical environment in which they live |
| adaptation | genetically based characteristic of an org that improves its ability to survive or reproduce in its environment |
| natural selection | evolutionary process in which individuals that possess particular characteristics survive or reproduce at a higher rate than other individuals because of those characteristics |
| producer | org that uses energy from an eternal source (sun) to produce its own food without having to eat another org |
| Net Primary Production (NPP) | amount of energy (per unit of time) that producers fix by photosynthesis or other means minus the amount they use in cellular respiration |
| Nutrient Cycle | cyclic movement of a nut between orgs and the physical environment |
| Evolution Defined as: | -change in genetic characteristics of a pop over time -descent with modification, process by which orgs gradually accumulate differences from ancestors |
| How does climate control where orgs live | - Temp regs rates of biochem react. and physiological activity - Geographic distribution is influenced by extreme conditions - Climate influences rates of abiotic processes (rock/soil breakdown) |
| Earth's solar energy | -1/3 reflected back out of atmosphere -1/5 absorbed by ozone, clouds, water vapor - 1/2 absorbed by land and water |
| latent heat flux | heat loss due to evaporation |
| sensible heat flux | energy transfer from warm air immediately above the earth surface to the cooler atmosphere by convection |
| Hadley Cell | created by large scale pattern of atmospheric circulation in each hemisphere |
| Polar Cell | cold dense air subsidies at poles and moves toward the equator |
| Ferrell Cell | midlatitudes; driven by movement of hadley and polar cells and by exchange of energy between tropical and polar air masses in a region known as the polar front |
| Major zones on earth created by Circulation cells | between 30°N and S is topics, between 30° and 60° N and S is temperate, above 60° N and S is polar |
| Trade Winds | winds blowing toward the equator from high pressure zones at 30° N and S |
| Downwelling | currents move toward the equator carrying cold water toward warmer tropical oceans |
| Upwelling | occurs where prevailing winds blow nearly parallel to coastline (wind in combo with coriolis effect —> water to flow away from coast and deeper cover waters replace them) |
| 3 major influences alter the global pattern of temperature: | ocean currents, distribution of land and water, elevation |
| lapse rate | decrease in temperature with increasing height above the surface; wind velocity also increases with increasing elevation because there is less friction with the ground surface |
| Vegetation affects climate via surface energy exchange | rough surface (savanna of mixed trees and grasses) —> greater transfer of energy to the atmosphere by wind than smooth surface (grassland) |
| intertropical convergence zone (ITCZ) | movement of the zone of maximum air uplift and precipitation in the hadley cells |
| hypolimnion | stable layer of densest, coldest water |
| El nino | -upwelling of deep ocean water off the coast of S. America stops as easterly winds weaken or sometimes shift to westerly winds -dry conditions in areas like Malay Archipelago, SE Asia, Australia -US and N. Mexico = increased precipitation |
| La Nina | -high pressure of the coast of S. america and low pressure in W. pacific - Causes drought in US and N. Mexico |
| Pacific Decadal Oscillation (PDO) | influences salmon numbers; linked to long-term droughts |
| biomes | large scale biological communities shaped by the physical environment in which they are found |
| river continuum concept | as stream flows up in size and up in detritus from veg adjacent to stream —> decrease in relative volume of water, particle size in streamed decreases —> greater establishment of aquatic plants downstream |
| lentic ecosystems | lakes and other still waters |
| pelagic zone | open water,; inhabited by plankton |
| Littoral Zone | nearshore zone where photic zone reaches to bottom |
| Estuaries | -junction of a river with the ocean -characterized by variations in salinity associated with the flow of fresh river water into the ocean -rivers bring terrestrial sediments to ocean and tide acts to keep them there enhancing productivity |
| Salt Marsh | terrestrial sediments carried to shorelines by rivers form shallow marshes dominated by vascular plants |
| Mangrove Forests | -shallow coastal estuaries and nearby mudflats in tropical/sub regions are inhabited by slat tolerant evergreen trees and shrubs -roots trap mud and sediment carried by water which build up and modify the shoreline |
| Rocky Intertidal Zones | -orgs arranged in zones associated with their tolerance for temp changes, salinity, desiccation, wave action, and interactions with other orgs -sessile (attached) orgs must cope with stresses, mobile can move to tide pools |
| Coral Reefs | -corals living in close association with algal partners form large colonies -coral obtain most energy from algae that live within their bodies while algae receive protection from grazer and nutrients from coral |
| Major Ecological Concepts | an org never does just one thing; matter always goes somewhere; no pop can increase in size forever; life impossible without specie interactions; an orgs resources are finite ; evolution matters; time matters; space matters |
| Tropical Rainforest | between 10°N and S Key factor = intense competition for light warm with high levels of precipitation little weather variation - plants grow continuously contain about 50% of earths species poor soils |
| Tropical forests and Savanna | 10-23.5°N and S seasonality of water (low in summer and high in winter) more shrubs and grasses than rainforests (Few trees) trees tend to be deciduous fire and grazing are important influences |
| Hot and Cold Deserts | 30N+S key factor = low water availability hot : low precipitation, high temps cold: same as above, but cold winters soil has low OM, plant cover sparse to absent animal abundance low, but biodiversity can be high |
| Temperate Grasslands | 30-50° N and S key factors= fire and grazing maintain grasslands warm, moist summers and cold dry winters high soil fertility commonly used for crops, livestock |
| Temperate Scrublands and Woodlands | 30-40°N and S Key factor = winter precipitation hot summers and wet winter characterized by evergreen shrubs and trees |
| Temperate Seasonal Forests (Deciduous) | 30-50N key factor = at least 50cm of precipitation per year deciduous and evergreen, but dominated by deciduous fertile soil, low levels of disturbance |
| Temperate Evergreen Forests | 30-50N and S key factor = evergreen trees wide range of conditions includes temperate rainforests Often high soil acidity few old growth forests remain (logging) |
| Boreal Forests (Taiga) | above 50N key factor = severe winters (subfreezing in some cases ) soils freeze (permafrost) cold air temp Composed primarily of conifers |
| Tundra | above 65N Key factors = cold temp, low precipitation diff from cold desert because latitude, permafrost low growing shrubs, forbs, grasses, lichen, moss |
| Ocean Zones | benthic = bottom pelagic = off the bottom (regardless of depth) photic = .5-200m intertidal = mean high water to mean low water of tides nearshore = continental shelf pelagic = past nearshore |
| Aerosol | can have cooling effect (like volcanoes) |
| Ecological responses to climate change | - Ice melting, earlier migration of birds, extinction of amphibians/reptiles, bleaching of reefs, fish die off in lakes, earlier spring greening off veg, shifting of range to higher elevations |
| adaptive evolution | process of change in which traits that confer survival or reproductive advantages tend to increase in frequency over time |
| Constraints to adaptation | lack of genetic variation evolutionary history : have or lack traits due to ancestry ecological trade offs: must perform essential functions |
| climate envelope | range of climate conditions under which a species occurs |
| ecotypes | pops with adaptations to unique environments |
| Ectotherms | ectotherms generally have greater tolerance for variation in body temp than endotherms relationship between surface area and volume —> size and shape constraint mobility - allows to adjust body temp by moving |
| Endotherms | -tolerate narrower range of body temp, however generate heat internally allowing them to expand geographic ranges and times of year can be active -rate of metabolic activity associated with external temp and rate of heat loss -insulation key |
| themo-neutral zone | basal/resting metabolic rate over a range of enviro temps |
| lower critical temp | when temp drops to a point at which heat loss is greater than metabolic heat production |
| How we study climate change | tree rings, corals, lake and ocean sediments, ice cores |
| Evolution by Natural Selection | variation in a pop variation has to be heritable certain traits confer differential survival / reproduction pops can grow rapidly but most individuals die before reproducing, or produce fewer than the maximum number of offspring |
| Directional selection | shift in traits over time (peppered moth changing from peppered to darker during coal) |
| Stabilizing Selection | common in stable enviro conditions; selection against extremes. Average remains the same, but the number of individuals with intermediate condition increases |
| Disruptive Selection | original pop differs from pop that’s selected against (intermediate selected against; favors extremes) |
| What limits ranges | enviro constraints (temp, water, nutrients) species interactions (bison limited with human hunting) geographic (history of speciation) |
| Environmental stress | enviro factor that decreases rate of some physiological process —> lowers potential for survival, growth, reproduction - Pops cope with via adaptation -Individuals cope with acclimatization |
| Why Temperature matters | extreme heat dentures enzymes cold temps slow reactions water freezes at 0 membranes can solidify at cold temps heat can lead to water loss |
| single celled orgs water conservation | generally need moist environments dormant stages adjust osmotic balance |
| Plant water conservation | only open stomata at night develop waxy leaves more roots or mycorrhizae relationship adjust osmotic balance |
| Animal water conservation | exoskeleton (insects) thick skin (reptiles) hair or feathers (mammals and birds) behavioral avoidance (nocturnal animals) |
| Conserving water tradeoffs (Animals) | mammal sweat glands help with cooling but req water tough skin may inhibit gas exchange behave avoidance may reduce time for feeding —> slower growth |
| Which statements are true about hot deserts | -low water availability is an important constraint on abundance of desert plants - succulent stems are common in hot deserts |
| semelparity | an individual only reproduces once |
| iteroparity | an individual reproduces multiple times |
| individuals cope with environmental stress through _______ | acclimatization |
| populations cope with environmental stress though ________ | adaptation |
| kinetic energy | associate dight motion of molecules that make up objects (touch) |
| what demands do different types of energy fulfill | radiant/chemical fulfill demands of growth and maintenance, while kinetic is important for controlling rate of activity and metabolic demand of orgs |
| allocation | relative amounts of energy or resources that an org devotes to diff functions |
| phenotypic plasticity | can produce continuous range (height vs. temp) or discrete types/ morphs (toads form omnivore or carnivore tadpole morphs) |
| isogamy | production of equal sized gametes |
| disadvantages to sexual reproduction | -individuals can only pass down half genetic content -recombination and independent distribution of chromosomes into gametes can disrupt favorable gene combos potentially reducing fitness -growth rate is only half that of asexual reproducing organisms |
| benefits to sexual reproduction | recombination promotes genetic variation — beneficial in a challenging environment |
| complex life cycle | -one in which there are at least 2 distinct stages that differ in their habitat, physiology, morphology -transitions are often abrupt |
| metamorphosis | abrupt transition in form from larval to juvenile sometimes accompanied by change in habitat |
| direct development | development from fertilized egg to juvenile occurs within an egg prior to hatching and no free living larval stage occurs (salamanders that lack gilled aquatic larval stage) |
| Lack Clutch Size | number of eggs per reproductive bout is limited by max number of young that parents can raise at one time to maturity which in turn is related to resource availability |
| PAR | Photosynthetically active radiation (visible light) = enough energy for photosynthesis |
| C3 | uptake of CO2, fixing of carbon via Calvin Cycle, production of sugars majority of plants use this wasteful of water |
| C4 | -separates carbon fixation and sugar production spatially -mesophyll cel: converts to 4 carbon compound which moves to Bundle Sheath cell -efficient use of water -maximum photosynthesis at high light levels, poor growth in shade -grass, corn |
| CAM | -separates carbon fixation and sugar production, but does temporarily instead of spatially -does carbon fixation at night, then during day releases to calvin cycle -close stomata during day and internally release CO2 for photosynthesis desert plants |
| Stoichiometry of autotrophs | high C:N ratios |
| stoichiometry of invertebrate heterotrophs | low C:N ratios |
| Type 1 Functional response | food capture determined by density of food (number of prey killed increases with prey density) |
| Type 2 Functional Response | Prey mortality declines with prey density (most common) |
| Type 3 Functional Response | Consumers increase search activity with increasing prey density |
| Optimal Foraging Theory | -orgs forage in such a way as to maximize their energy intake per unit time -goals: increase calories, decrease time/output |
| constraints on homeostasis | nutrients, abiotic conditions, energy |
| adaptations for homeostasis | growth, survival, reproduction |
| 3 Major goals | Survival, growth, reproduction |
| principle of allocation | evolution will process phenotypes that allocate limited resources between competing physiological processes in such a way as to maximize fitness |
| Senescence | decline in fitness of an org from physiological deterioration |
| type 1 survivorship trend | greatest number of survivors are young and die off with age (humans) |
| type 2 survivorship trend | steady decline in survival from young to old (song birds, rodents,) |
| type 3 survivorship trend | large die off young, older individuals tend to survive (marine organisms) |
Created by:
bouzianeju