The Biosphere Ch 3; Essential Standards: 2.1.1, 2.1.3

WHAT IS ECOLOGY? OBJ define ecology as the study of interactions between organisms and their environment OBJ identify ecological levels of organization

What is Ecology? The study of interactions between organisms and their environment Biosphere = the part of Earth that can sustain life

Levels of Organization Species = group of organisms that can interbreed and produce fertile offspring Population = group of the same species that live in the same area Communities = multiple populations in an area Ecosystem = all of the organisms in a place together with the entire environment (living and nonliving) Biome = a group of ecosystems with similar climate and similar dominant communities

Organization

Ecological Methods Three basic research approaches: –Observing = first step in asking ecological questions –Experimenting = test hypotheses, could be in the lab or in the field –Modeling = used because observations can take too long; consist of math formulas based on data collected

ENERGY FLOW OBJ describe flow of matter and energy in an ecosystem

Energy Flow: Producers The source of energy for all life = sun Autotrophs: organisms that are able to make their own food (sunlight/chemical energy) –Producers

Energy from the Sun Photosynthesis –Very crucial for life –Carbon dioxide -> oxygen –Plants/algae Chemosynthesis = production of energy from chemical energy (bacteria)

Photo and Chemosynthesis

FOOD WEBS OBJ create and interpret food chains and webs

Consumers Heterotrophs = organisms that eat other organisms to obtain energy –Consumers: herbivores, carnivores, omnivores, detritivores, and decomposers –Detritivores = feed on plant and animal remains (dead matter); ex: crabs, earthworms, mites, snails –Decomposers = break down organic matter; ex: bacteria and fungi

Consumers

Feeding Relationships Energy flows through an ecosystem in one direction, Sun -> producers(autotrophs) -> consumers (heterotrophs) Food chains

Food Webs More complex than food chains –relationships between many organisms in an ecosystem in a network of complex interactions Multiple food chains together for an ecosystem

Food Webs

ENERGY FLOW OBJ describe flow of matter and energy in an ecosystem OBJ interpret the pyramids of energy and matter

Trophic Levels Each step in a food chain or a food web –Producers are the first step –Consumers make up each step after the producers Each consumer depends on the level below it for its energy

Ecological Pyramids Diagram that shows the relative amounts of energy (matter) contained in each trophic level of a food chain or food web

Energy Pyramids Theoretically no limit to the number of trophic levels –finite amount of energy is passed from one level to the next, organisms use the energy obtained for life processes Only 10% of the available energy of one trophic level is passed to the next level

Energy Pyramids

Biomass Pyramid biomass - The total amount of living tissue in a trophic level –grams of organic matter in a unit of area Pyramid gives the amount of potential food available for each trophic level in an ecosystem

Biomass Pyramid

Pyramid of Numbers Based on the numbers of individual organisms at each trophic level There may be less producers than there are consumers –Forest example: a tree has a lot of biomass, but it is only one organism; many insects live in the tree, but they do not have much biomass or energy (not typical)

Pyramid of Numbers

RECYCLING IN THE BIOSPHERE OBJ describe the various cycles in nature

Recycling in the Biosphere Unlike energy, matter is recycled between ecosystems Biogeochemical cycles = elements, chemical compounds, and other forms of matter passed from one organism to another

Water Cycle

Moves between the ocean, atmosphere, and land Involves evaporation and transpiration

Nutrient Cycle All chemical substances an organism needs to sustain life are nutrients –build tissues and carry out life functions Include water passed between organisms and the environment

Carbon Cycle

Carbon Cycle Processes that move CO2 through the cycle: –Biological processes (photosynthesis, respiration) –Geochemical processes = erosion and volcanic activity –Mixed biogeochemical processes = burial and decomposition –Human activities = mining, cutting/burning forests

Nitrogen Cycle Nitrogen ( part of amino acids) and makes up 78% of the Earth’s atmosphere Nitrogen fixation bacteria in the soil convert nitrogen gas into ammonia. Other soil bacteria convert this ammonia into nitrates/nitrites that organisms can use to make amino acids Consumers eat these producers and use the nitrogen to make their own proteins When an organism dies, decomposers return the nitrogen to the soil as ammonia Some soil bacteria at this point turn nitrates and nitrites into nitrogen gas through denitrification

Nitrogen Cycle

Phosphorous Cycle Phosphorous is required to make DNA and RNA Remains mostly on land in rock and soil minerals

Nutrient Limitation Primary productivity = the rate organic matter is created by producers Limiting nutrient = a nutrient that is scarce or slow cycling that limits the ecosystem –Algal bloom = increase in the amount of algae in an ecosystem because of increased fertilizer from runoff

Algal Bloom

Objectives SWBAT define evology as the study of interactions between organisms and their environment SWBAT identifty ecological levels of organization SWBAT describe the properties of a population and interpret population curves SWBAT identify the carrying capacity of an environment SWBAT compare and contrast exponential and logistic population growth. WBAT compare and contrast habitat and a niche SWBAT define a limiting factor and provide examples WBAT define the competitive exclusion principle and compare/contrast interspecifc and intraspecific competition SWBAT define and provide examples of 3 forms of symbiosis: mutualism, commensalisms, and parasitism SWBAT create and interpret food chains and webs SWBAT describe flow of matter and energy in an ecosystem SWBAT interpret the pyramids of energy and matter SWBAT define and describe the laws of conservation of matter and energy SWBAT describe the process of succession and provide examples of primary and secondary sucession as a climax community SWBAT describe the various cycles in nature SWBAT describe terrestrial and aquatic biomes SWBAT explain natural systems such as climate change, ozone production, erosion, deposition