Ecosystems: Primary Productivity & Biomass

• Unit 5 focuses on the Environment Level - Energy in Ecosystems.
• The lessons cover primary productivity, biomass, energy transfers across trophic levels, factors affecting populations, carrying capacity, competition, and biodiversity and ecosystem resilience.

Lesson 1: Primary Productivity and Biomass

• Energy for building organic material (biomass) originates from the sun, considered a limited resource.
• Productivity refers to the rate at which energy is stored in organic matter.
• Gross productivity measures the total energy captured, while net productivity indicates how much energy is stored as biomass.
• Insolation, biomass, biological productivity, producers, and net primary productivity are all key vocabulary for ecosystems.
• Plants use photosynthesis to convert light energy to chemical energy, which is stored in biomolecules like glucose, starches, lipids, and proteins.
• Production involves the creation of organic biomolecules and is measured as an amount per area like kcal/m^2.
• Biomass is the term for all organic material produced.
• Biomass can be defined as the total mass of living organisms such as plants and animals within a given area, excluding water.
• Productivity is production measured per unit of time, expressed as energy captured per unit area per unit time, i.e J/m^2/yr.
• Gross productivity is the total energy acquired from photosynthesis.
• Net productivity is the energy remaining for growth after respiration, which is the production of new biomass.
• Net Primary Productivity (NPP) equals Gross Primary Productivity (GPP) minus Respiration (R).

Lesson 2: Energy Transfers across Trophic Levels

• Organisms use much of the energy they take in for respiration, and store the remaining energy as net productivity or new biomass
• Energy is attained by consuming biomass, except for producers.
• Trophic levels organize organisms based on their diet.
• Energy transfers between trophic levels are inefficient, typically around 10%.
• Trophic levels, trophic pyramid, efficiency, herbivore, omnivore, carnivore, and decomposer are key vocabulary about trophic levels.
• Producers such as plants create their own food using inorganic building blocks like CO2 and H2O using solar energy.
• Consumers are not able to produce their own food and obtain energy and matter through consuming and digesting biomass.
• Consumers are classified by diet as herbivores, omnivores, carnivores, detritivores and decomposers.
• A food chain models the feeding relationships and the transfer of energy and matter between groups of organisms in an ecosystem.
• A trophic level describes an organism's position in a food chain or web.
• Gross Secondary Productivity is the total energy consumed by consumers, which equals energy in food eaten minus the energy lost in feces/waste.
• Net Secondary Productivity is the amount of energy remaining after respiration that goes to animal growth which is the energy used to make biomass.
• A pyramid of energy illustrates the energy available at each trophic level with the majority of energy lost at each level.

Lesson 3: Food Chains and Food Webs

• Solar energy is finite, limiting productivity within an area.
• Higher trophic levels need more solar energy to produce equal amounts of biomass.
• Detritivores and decomposers help consume the biomass that has been shed from each trophic level (detritus and waste).
• Food chains and food webs are key vocabulary relating to energy transfers
• Food chains are simplified models of energy flow in complex system, energy flow is illustrated with arrows.
• Food webs show multiple organisms per trophic level and provide more complete models to show multiple relationships in an ecosystem.
• Energy captured by primary producers through photosynthesis is converted to heat which goes back to the atmosphere via longwave IR radiation.

Lesson 4: Factors Affecting Populations

• Organisms are organized into levels such as species, populations, communities, and ecosystems.
• Population growth is influenced by biotic ad abiotic factors.
• Vocabulary for populations include: biotic, abiotic, species, population, community, ecosystem, carrying capacity, density-dependent factors, biotic potential, and logistic growth.
• Biotic factors are interactions between living organisms such as predation and food availability.
• Abiotic factors are physical factors including non-living things like temperature.
• Organisms include a single individual plant, animal, or microbe.
• A species includes a group of organisms that can interbreed and produce offspring that can reproduce.
• A population is the individuals of the same species living in the same area at the same time.
• A community is all of the populations living in the same area.
• An ecosystem includes all living iotic and non-living abiotic.
• Population size is the total number of individuals in an area at a given time.
• Density is the number of individuals per unit area.
• Density-dependent factors are factors that affects population growth as it relates to density such as competition for food, habitat, water, light, or disease.
• Density-independent factors are factors that affect population growth irrespective of population size such as natural disasters.
• Biotic potential refers to the capacity of organisms reproduce rapidly.
• Logistic growth occurs when a population's growth rate slows as it reaches the carrying capacity due to lack of resources.
• Environmental factors limit the growth potential of population, this is environmental resistance.
• Carrying capacity is the maximum population of a species that can be sustained in its ecosystem

Lesson 5: Carrying Capacity, Competition, and Biodiversity

• Population growth in one population occurs at the expense of other populations it competes with.
• Genetic, species, and habitat diversity are three types of biodiversity.
• Species richness and evenness measure biodiversity.
• Diversity enhances resilience in organisms, populations, and ecosystems.
• Key vocabulary surrounding biodiversity: Biodiversity, genetic diversity, species diversity, habitat, habitat diversity, and resilience.
• Limited resources leads to competition and a limitation on carrying capacity which affects both populations.
• Feedback occurs when environmental resistance enforces carrying capacity.
• Genetic diversity refers to how much variation there is between individuals in a single population (gene pool).
• High genetic biodiversity means there is a large variety of traits.
• High genetic biodiversity means that individuals will be better equipped to resist disease and survive events.
• Low genetic diversity means there is greater risk that a species will be wiped out because they are very similar.
• Species diversity describes the number of different species present in an area, accounting also ofr their relative abundance.
• Evenness is diversity in communities, measuring their species' proportions.
• High species diversity ecosystem includes greater number of successful species that leads to stable ecosystem.
• High species diversity includes complex food webs, and less likely to impact when there are environmental changes.
• Habitat diversity describes the range of habitats present.
• Ecosystems with high habitat diversity will have complex physical structures.

Lesson 6: Biodiversity and Ecosystem Resilience

• Lesson centers on connecting biodiversity affects an ecosystem's ability to resist change.