Transcript Ecology
Ecology key terms Ecology Key Terms • ECOLOGY • HABITAT • COMMUNITY • ECOSYSTEM • ABIOTIC FACTOR • BIOTIC FACTOR • BIODIVERSITY • PIONEER SPECIES Ecology Key Terms • FOOD CHAIN • FOOD WEB • AUTOTROPH • HETEROTROPH • HERBIVORE • CARNIVORE • OMNIVORE • DETRITIVORE • PREDATION • SYMBIOSIS • MUTUALISM • COMMENSALISM • PARASITISM • NICHE Biomes • A biome is a large geographical area of distinctive plant and animal groups, which are adapted to that particular environment. The climate and geography of a region determines what type of biome can exist in that region • Try to remember the climate or plants & animals • Can be terrestrial, freshwater, or marine Estuary Biomes • Tropical Rainforest - Wet, humid, warm year-round, tall trees w/ undergrowth, comp. for sunlight, high biodiversity - provides effective response to change, occurs through speciation • Desert - low precipitation, may be very hot or very cold, low pop. density, succulents and deep rooted shrubs - plants and animals adapted for water conservation Biomes • Savanna - seasonal rainfall, long dry season, some trees adapted to long dry season, grasses and forbs, large grazing animals, watering holes • Chaparral - Coastal, rainy winters and long, hot, dry summers. CALI!, fire common, drought common, good plant diversity, browsers and small mammals Biomes • Grassland - the great plains, semi-arid, perennials, large grazing animals, ideal for agriculture • Deciduous/Temperate Forest - eastern US, cold winters w/ snow, warm summers, broadleaf plants which drop their leaves, hibernation and migratory birds Biomes • Taiga/ Coniferous forest - long, cold winters and short cool summers, conebearing trees, large mammals (moose, bears), few reptiles • Tundra - long, cold winters, very short growing seasons, lichens, mosses, permafrost, large, grazing mammals. Limiting Factors • Aspects of the environment which will restrict population growth • 2 types of limiting factor: • Density-dependent - greater impact as population increases • Density-independent - same impact regardless of population size/density • Determine carrying capacity ( K ) Hardy Weinberg Law • If certain criteria are met, then allelic and genotypic frequencies will remain stable over time. • Criteria: large pop., random mating, no migration (gene flow), no mutations, no selection or genetic drift • p+q=1 p2 + 2pq + q2 = 1 • p - allelic freq. - dom. allele • q - allelic freq. - rec. allele • p2 - genotypic freq. - hom. dom. • q2 - genotypic freq. - hom. rec. • 2pq - genotypic freq. - heterozygous Ecosystems • A biological community and it’s abiotic factors • Includes all of the interactions within the system - interdependence • biotic - biotic • biotic-abiotic • Energy travels through an ecosystem - in and out Trophic Levels • Autotrophs - self + food, producers, most energy, biomass, largest pop. Apex Predators • Heterotrophs - other + food, consumers, progressively less available energy, biomass, and numbers as you move up through trophic levels • Types of eaters: herbivores, carnivores, omnivores, detritivores - a.k.a. decomposers - return essential minerals to the soil Food Chains + Food Webs • Display the transfer of energy in a system • Food chain - one pathway • Food web - all pathways, alternative pathways • Arrows indicate feeding relationships • Only arrows leaving an item = producer Biogeochemical cycles • Continual, cyclical transfer of essential substances • Part of transfer is through living things because these substances are essential for life • Carbon, Nitrogen, Phosphorus • Carbon - carbon-based life, photosynthesis, cellular resp., fossil fuels, dissolved CO2 in oceans, detritivores • Nitrogen - req. for amino acids and nucleic acids, atmospheric N, nitrogenfixing soil bacteria, legumes and root nodules, ammonification --> ammonia, nitrification --> nitrites --> nitrates - all used by plants, denitrification --> releases N back into air • Phosphorus - ATP, NADP, Ca:P balance, released from rocks, dissolved in H2O, incorporated into plants and travels through food chain Hydrologic Cycle • Another essential cycle that supports life. • Evaporation, Condensation, Precipitation, Surface Runoff, Infiltration/Percolation, Groundwater, Aquifers, Recharge, Plant Uptake, Transpiration • Also involved in the cycling of other minerals • Plant matter increases percolation and prevents surface runoff Niche and Symbiosis • Species fill a niche within their ecosystem - a special role which incorporates their requirements and the survival strategies, feeding relationships and symbiotic relationships they engage in • Symbiosis - close, permanent, different species • Mutualism - 2 benefit • Commensalism - 1 benefits,1 unaffected Ex. Epiphytes • Niche includes habitat - the physical place an organism lives in and shares with other organisms Habitat, Niche, and Competition • Species in the same habitat with overlapping niches will compete with one another for resources • Outcomes: • limited overlap: both may survive • great overlap: competitive exclusion - one survives, the other does not • Don’t forget that individuals within a population compete as well! • Outcome: • Fittest survive, but we will save evolution for another time... Invasive Species • Newcomers to a habitat may disrupt the interactions between predators and prey and create imbalance within a system. • Typically, these new, exotic species lack a predator, experience a population explosion, and outcompete native species for resources • Leading cause of extinctions. • As native populations become smaller, there is reduced genetic variability (greater chance of inbreeding + genetic drift) and are subject to rapid change due to chance Invasive Species and Population Growth • Invasive species that are r-strategist will be particularly successful. • r- strategists: mature early, reproduce quickly, have many offspring and limited parental care, and experience boom and bust periods • Boom periods demonstrate exponential growth - J-shaped curve. • Requires resources! Logistic Growth • When population size is restricted by density dependent limiting factors we would see a sigmoid (s-shaped) curve. • The plateau created represent carrying capacity (K) - the maximum number of organisms the environment can support. • K-strategists - mature later, few offspring, extensive parental care, growth rate slows as environmental resistance increases. Size, Density, Dispersion • Population size (N) - how many? • Population Density - how many per unit of space? • Population dispersion - how is the population arranged in that space? • clumped, even, random