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Biology & Geology 100 • Introduction to key biological concepts • Background for tomorrow’s field trip What is Natural History? • the study of the natural environment with an emphasis on identification, formation/origin of physical features, life-history, distribution, abundance, and inter-relationships. – It often and appropriately includes an aesthetic component. The Natural Environment=Ecosystems • An interacting unit of living and non-living components. – Living Things (biotic) • Plants, algae, animals, fungi, microbes • All the living things of an area = community – Non-living things (abiotic)—the physical environment • Water, temperature/heat, sunlight, wind/air, soil/minerals, nutrients (found in air, water, & soil) etc… – Created by geological (sometimes astronomical) factors The Natural Environment = Ecosystems: An interacting unit of living and non-living components Abiotic = non-living • Sunlight & Heat • Air • Water • Earth (minerals/soil) Biotic = living • Animals • Plants • Algae • Microbes Biological Factors Physical Factors Homage to Geology • Geological forces creates diversity in landscape and abiotic variability • Variation in the physical landscape habitat diversity habitat diversity biological diversity – opportunity for different forms of life to evolve and co-exist Major Ecosystem Interactions • • • • • • • Energy production, transfer, and loss Nutrient movement Tolerance competition predation Symbiosis Ecological Succession Food WebsTransfer = energy =and nutrient movement Energy food chains/webs Sun = initial source of energy Producers: --Plants --algae Herbivores carnivores consumers Decomposers: --fungi --bacteria Interactions and flow within an ecosystem Nutrient Cycling: an example showing interactions between physical environment and living things • nutrients pass from one organism to the next through feeding and are then cycled back through the ecosystem Tolerance Ranges • For every physical aspect of the environment and for every substance used by an organism : – (e.g., temperature, water, wind, minerals, nutrients, pH, etc): – There is a minimum amount needed and a maximum amount that can be tolerated. – Between the minimum needed and maximum tolerable is the “tolerance range) Tolerance range a simple schematic too dry Tolerance range for the grass to survive there is enough to meet the grasses needs, but not too much too wet for the grass to survive water wet dry Competition Competition for: • Food • Shelter • Light • water • space • Mates Competition happens: • Between individuals of same species • Between different species – Competitive exclusion • Influences where organisms are located Competitive Exclusion • Two species that compete for the same resources in the same way cannot coexist long term – The species that is the better competitor (in a given environment) will exclude the other specie at that location this is competitive exclusion Tolerance range + Competition a simple schematic Limit due to tolerance Limit due to competition = competitive exclusion too dry Tolerance range for “grass” Bush is better competitor in this area; excludes grass water wet dry Predation • One thing eats another (e.g., one consumer eats another) • Energy and nutrient acquisition seal Distribution of Living Organisms: across the landscape is determined by a combination of (things are where they are because) the following • Physical factors – specifically tolerance to physical factors and availability of abiotic resources • Competition • Predation • Dispersal – has the organism been able to get to an area from its existing range Common Factors Determining Distribution (i.e., where things are found) Found in this range • Intolerant (too much) • Predation • Out competed • Intolerant (too little) • Predation • Out competed Also dispersal: is the organism or its offspring able to get to an area. If the organism is incapable of reaching an area (or has not yet reached an area) then it won’t be found there. barrier to dispersal (no lizards here) • Intolerant (too little) • Predation • Out competed • Intolerant (too much) • Predation • Out competed Major Ecosystem Interactions • Symbiosis: very/unusually close relationships among organism Symbiosis • Particularly close relationships between two or more organisms – Often (but not always) refers to situation when one organism lives in or on another organism Host (bigger) • Mutualism • Commensalism • Parasitism xx Symbiot (smaller) • Adaptation: – A characteristic that makes an organism better suited to its environment • better able to tolerate, compete, be a predator or escape predation, and reproduce Our Goal = biologically interpret/assess 1. Why is this place the way it is; why are the things that are here, here? 2. What can I tell about this place from what I see? Niche • The role an organism plays in its environment • How an organism “makes its living”. • All the ways a species uses its physical environment/resources and all its interactions with other living things. • Examples of what a niche contains: – – – – – – – What it eats When it eats How it gets food What eats it When is it active What wastes does it put back into the environment What resources it needs (nutrients, space, shelter, etc) Terrestrial Environments: it all begins with plants Terrestrial Environments: it all begins with plants (or some other producer) THE CENTRAL IMPORTANCE OF PLANTS (and many producers) • They form the base of the food chain • Plants cannot move (animals can). – they are reflective of the physical conditions at a particular area. • The type of plants in a location influences the type of animals at that same location • Terrestrial ecosystems/communities are usually identified by the plants groups they posses. What is a community • A group of species that grow together in sites that are environmentally similar • They exist together because: – they have similar tolerance ranges – They inhabit different niches • Don’t compete too directly HOW PLANTS WORK • Water (from soil) + CO2 (from air) + Sunlight Sugars photosynthesis • This happens mostly in leaves HOW PLANTS WORK pt 2 • Plants loose water through leaves • They have to lose water to move water. – necessary to get water to leaves for photosynthesis – But too much water loss is bad Leaves are compromises between: Water loss photosynthesis HOW PLANTS REPRODUCE • plants do it with animals or the wind…or water How Plants Work • Seeds (with embryo) are dispersed Asexual Reproduction in Plants: some plants do it by themselves Plant Reproduction: asexual v. sexual ASEXUAL SEXUAL • Fast • Cheap/low energy • Easy • Slower • Takes more energy • More risky BUT • Produces offspring that are identical to parent BUT • Produces variable offspring that could be better adapted to current or future conditions Abiotic (non-living) factors affecting the distribution of plants & plant communities • Temperature • Water Large Scale • Sunlight • Wind • Soil Conditions – pH – salt content/salinity – sandy – tightly packed – organic content – Slope aspect Small Scale Water Availability Productive Temperature Photosynthesis and Growth Right temp and water amount photosynthesis food growth and reproduction “productivity” Within a zone, there is further fine scale variation based on: • small scale differences in water – (creeks, ponds, slope aspect, etc…) – create Riparian zones • temperature – (depressions, slope aspect) • sunlight – (clearings, slope aspect, canopy shading) • soil – (pH, sandy, gravelly, salinity, mineral, organic, nutrient levels, etc..) • wind – (exposed or protected) Increasing Altitude = • Decreasing Temperature (~3 deg. F per 1000’) • More rain/water (precipitation, but….) • Shorter growing seasons Colder Hotter Slope Aspect: North v. South Slope Aspect: east v. west Chaparral Biome Mediterranean Climate & Chaparra Biome • Mid-latitude (30 deg), coastal regions • Sea level – ~5500’ • Seasonal precipitation – Precipitation 8-20”, mostly in winter (Dec – Mar) – Prolonged period of drought (~Apr-Nov) – Rain/precipitation highly variable from year to year. • Seasonal Temperatures – long dry summers 80-100+ F – spring, winter, fall cool – winters moderately cold in coastal regions, but higher elevation can experience frost and small amounts of snow In more coastal regions: • Santa Ana winds in summer (hot and dry) • fog, mist, marine layer in some seasons Common Communities of the Mediterranean Climate in So.CA • Sage scrub – – – – – – Closer to coast, lower elevations 8-10” of rain per year, but with moderate temperatures sub-shrub dominant drought deciduous frost intolerant Types • Coastal • Inland • succulant • Chaparral (true/hard chaparral) – – – – – – More inland, higher elevations Wetter (~15-20” of rain) shrub dominant Generally evergreen dominant frost tolerant – snow tolerant Types: • • • • Lower v. Upper v. maritime v. desert Chamise v. mixed Oak woodland Riparian – Mesic community in canyon bottoms (and where water is more abundant) • • Grassland Conifer Forest Hwy 2 Field trip • Changes with altitude • Changes with slope aspect • Changes due to localized water availability— i.e., permanent water/streams • Effects of fire?