Lecture 3: Ecology PDF

Lecture 3: Ecology Biosphere The part of Earth ECOLOGY that contains all ecosystems...

Lecture 3: Ecology Biosphere The part of Earth ECOLOGY that contains all ecosystems Composed of Definition numerous complex ecosystems The study of the interactions of An ecosystem living things (biotic factors) with involves each other and their physical interactions to environment (abiotic factors) maintain balance between ECOLOGICAL LEVELS abiotic (physical) and biotic Molecules Group of atoms; (living) factors smallest unit of most chemical SUSTAINED ECOSYSTEM compounds An ecosystem is self-sustaining if the following requirements are met: Cells Smallest A constant source of energy and a functional unit of living system capable of life incorporating this energy into organic molecules Groups of Tissues, organs, A cycling of materials between Cells and organ organisms and their environment systems Organism Individual living In all environments, organisms with similar thing needs may compete with each other for resources, including food, space, water, air, Population Group of and shelter organisms of one type that live in ABIOTIC FACTORS the same area Those physical and chemical factors which affect the ability of organisms Community Populations that to survive and reproduce live together in a Examples of abiotic factors: defined area ○ Intensity of light All interacting ○ Range of temperatures populations in a ○ Amount of moisture given area ○ Type of substratum (soil or rock type) Ecosystem Community and ○ Availability of inorganic its non-living substances (minerals) surroundings ○ Supply of gases such as Functioning oxygen, carbon dioxide, and together as an nitrogen independent and ○ pH levels relatively stable Abiotic factors may act as a limiting system factor, determining the types of Lecture 3: Ecology organisms that exist in that ○ Living together with another environment organism in close association BIOTIC FACTORS Mutualism Both All the living things that directly or organisms indirectly affect the environment benefit from Organisms, their presence, parts, each other interactions, and wastes are all biotic factors Commensalism One organism is benefited CARRYING CAPACITY and the other Maximum number of organisms the is unharmed resources of an area can support One benefits, The carrying capacity of the one doesn’t environment is limited by the care available abiotic and biotic (nonchalant resources, as well ad the ability of ‘yan sha) ecosystems to recycle the residue of dead organisms through the Parasitism Parasite activities of bacteria and fungi benefits at the expense of NUTRITIONAL RELATIONSHIPS the host Autotrophs (Plants; Flora) ○ Can synthesize their own FOOD CHAINS AND WEBS food from inorganic If an ecosystem is to be compounds and a usable self-sustaining, it must contain a energy source (sun) flow of energy Heterotrophs (Animals; Fauna) Those life activities that are ○ Can not synthesize their own characteristic of living organisms food and are dependent on require an expenditure of energy other organisms for their The pathways of energy through the food living components of an eco system ○ Types of heterotrophs: are represented by food chains and → Saprophytes (bacteria food webs and fungi Producers (plants) convert the → Herbivores (plant based) radiant energy of the sun into the → Carnivores (meat based) chemical energy of food - Predators - animals which kill and consume their prey Food Chain Involves the - Scavengers - those transfer of animals that feed on energy from other animals that green plants they have not killed through a series → Omnivores (plant and of organisms meat based) with repeated stages of eating and being eaten SYMBIOTIC RELATIONSHIPS Symbiosis Lecture 3: Ecology ○ Through decomposition, chemical substances are returned to the environment where they can be used by other living organisms ENERGY FLOW Energy flows through ecosystems in Food Web The flow of one direction, typically from the Sun, energy and thorough the photosynthetic materials is organisms, including green plants much more and algae, through herbivores, to complicated carnivores, and finally, decomposers than illustrated by any one food chain Many interactions occur along the food chains of any community There is a decrease in the overall energy in each level as you move up the food web There is much more energy in the FOOD WEB INTERACTIONS producer level in a food webthan at Producers (plants) the consumer levels ○ The energy of the community Energy levels: is derived from the organic 100% → 75% → 50% → 25% → 0% compounds in plants Primary Consumers (herbivores) ENERGY TRANSFER ○ Feeds on plants (mice, Each consumer level of the food grasshoppers, and rabbits in pyramid utilizes approximately 10% the web above) of its ingested nutrients to build new ○ May include omnivores tissue, representing as food for the Secondary Consumers (carnivores) next feeding level ○ Feeds upon other consumers The remaining energy is lost in the ○ May include omnivores form of heat and unavailable Decomposers (bacteria and fungi) chemical energy, eventually, energy ○ Break doen organic wastes is lost and is radiated from the Earth and dead organisms to Thus, an ecosystem can not survive simpler substances without the constant input of energy from the sun Lecture 3: Ecology exist in balance with each other and BIOMASS their environment Amount of organic matter The climax community of a region is The decrease of energy at each always its dominant plant species successive feeding level (trophic Persists until a catastrophic change level) means that less biomass can of a major biotic or abiotic nature be supported at each level alters or destroys it Total mass of carnivores in a ○ Example: forest fires, floods, particular ecosystem is less than the abandoned farmlands total mass of the producers The ecosystem is likely to recover in stages that eventually result in a stable system similar to the original one FLORA Plant species Dominate in the sense that they are the most abundant food SUCCESSION sources Replacement of populations in habitat as it moves toward a stable state (determined by changes in Plant Major limiting plants) succession factor fir animal Environment may be altered through succession substantial ways, resulting in long-term gradual changes until a Animal As the plant stable system is formed succession community It is depended on the climatic changes, so will limitations of the geographical area the animals PIONEER ORGANISMS Climax communities are identified The first organisms to inhabit a by the dominant species—the most given location influential specie Modifies their environment where Competition more advanced organisms can live ○ Occurs when two different Primary succession species or organisms living in ○ Development of plant the same environment communities on newly (habitat) utilize the same formed habitats that limited resources (food, previously lacked plants water, space, light, oxygen, Secondary succession and minerals) ○ Return of an area to its ○ The more similar the natural vegetation following requirements = more a disruption or removal of competition the original climax community COMPETITIVE EXLUSION PRINCIPE CLIMAX COMMUNITY If two different species compete for A self-perpetuating community in the same food source or which populations remain stable and reproductive sites, one specie may be eliminated Lecture 3: Ecology This establishes one specie per niche in a community Niche Job The organism’s role in the community, particularly its role in relation to food with other species Habitat A place where a plant or animal can get food, water, shelter, PHOSPHORUS CYCLE and space it needs to live MATERIAL CYCLES In a self-sustaining ecosystem, material must be cycled among the organisms and the abiotic environment Same materials can be reused CARBON CYCLE COMPOSITION OF AIR Nitrogen (78%) Oxygen (20.9%) Other gases (>0.17%) Argon (>0.9%) Carbon dioxide (0.03%) WATER CYCLE Involves the processes of photosynthesis, transpiration, evaporation and condensation, NITROGEN CYCLE respiration, and excretion Lecture 3: Ecology Biomes - Composes of Oceans 70% of the Earth’s surface Contains many different organisms Provides most of the Earth’s food nutrients Most oxygen produced BIODIVERSITY Freshwater Ponds, lakes, Biomes rivers, and The differences in living things in an streams ecosystem ○ Increased biodiversity = increased stability LAND BIOME Ensures the availability of a rich Represents the Earth’s ecosystem in variety of genetic material land Adds aesthetic qualities to the environment DESERT Super dry air MONOCULTURE Little rain (less than 10 inches a Planting one specie over a huge year) area High daytime temperatures More vulnerable to predation or Lots of wind disease Typical animals include: ○ Insects ○ Reptiles BIOMES OF THE EARTH ○ Birds Biome ○ Various mammals ○ A large geographical community that has a TUNDRA particular type of climax Extremely short growing seasons (6 community to 10 weeks) ○ Made up of all the habitats in Long, cold, dark winters (6 to 10 a given region and climate months) Low precipitation AQUATIC BIOME Snow provides insulation Represents the marine ecosystem on Wildlife include: Earth ○ Birds Characteristics: ○ Reindeer ○ Temperatures do not vary as ○ Foxes much as land biomes (water ○ Bears absorbs and releases heat) ○ Seals ○ Organisms must maintain ○ Walruses water balance Types of Aquatic Biomes PRAIRIE/GRASSLAND Temperatures vary from summer to Marine Salt water winter Lecture 3: Ecology Moderate rainfall Typical animal life include: ○ Jack rabbits ○ Deer ○ Foxes ○ Coyotes ○ Birds FOREST Covers ⅓ of the Earth’s area Dominated by trees and woody vegetation Precipitation is distributed evenly throughout the year Animal life include: ○ Bears ○ Deer ○ Rodents ZOO Man-made habitat A place where people keep and display animals Important for 3 major reasons: ○ Recreation and education ○ Wildlife conservation ○ Scientific studies DISRUPTION OF EXISTING ECOSYSTEMS Urbanization ○ Growth of cities has destroyed land and wetlands ruining natural habitats Importation of Organisms ○ Organisms without any known predators in the area Poor farming practices ○ Overuse of fields, over grazing by animals, and erosion of land Misuse of pesticides ○ Use of pesticides has disrupted food chains