13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C KEY CONCEPT Ecology is the study of the relationships among organisms and their environment.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Ecologists study environments at different levels of organization. Ecology is the study of the interactions among living things, and between living things and their surroundings.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Organism An organism is an individual living thing, such as an alligator.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Organism Population A population is a group of the same species that lives in one area.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Organism Population Community A community is a group of different species that live together in one area.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Organism Population Community Ecosystem An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Organism Population Community Ecosystem Biome A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there.

13.1 Ecologists Study Relationships TEKS 2F, 3E, 10C Ecological research methods include observation, experimentation, and modeling. Observation is the act of carefully watching something over time. Observations of populations can be done by visual surveys. –Direct surveys for easy to spot species employ binoculars or scopes. –Indirect surveys are used for species that are difficult to track and include looking for other signs of their presence.

Ecological Methods Because this is not a controlled experimental laboratory… –Observing the ecosystem (footprints, scat, counting organisms, signs of life) –Experimental simulations of nature in a lab –Computer models based on past data to predict future trends

Section 2

13.2 Biotic and Abiotic Factors TEKS 12F KEY CONCEPT Every ecosystem includes both living and nonliving factors.

13.2 Biotic and Abiotic Factors TEKS 12F An ecosystem includes both biotic and abiotic factors. Biotic factors are living things. –plants –animals –fungi –bacteria plants

13.2 Biotic and Abiotic Factors TEKS 12F Abiotic factors are nonliving things. –moisture –temperature –wind –sunlight –soil moisture sunlight

13.2 Biotic and Abiotic Factors TEKS 12F A keystone species is a species that has an unusually large effect on its ecosystem. creation of wetland ecosystem increased waterfowl Population increased fish population nesting sites for birds keystone species

Section 3 Energy Transfer

What is the main source of energy for all Ecosystems?

From the sun, plants can make their own food by photosynthesis and other organisms can feed on them. Some other organisms can make their own food from inorganic compounds (chemicals not containing carbon) using chemosynthesis.

13.3 Energy in Ecosystems TEKS 11C, 12C Producers provide energy for other organisms in an ecosystem. Producers get their energy from non-living resources. Producers are also called autotrophs because they make their own food.

Autotrophs/Producers- organisms that can make their own food from the sun or chemicals organisms that can make their own food from the sun or chemicals Plants capture sunlight and convert CO 2 and water into sugar (food) and O ₂ by photosynthesis.Plants capture sunlight and convert CO 2 and water into sugar (food) and O ₂ by photosynthesis. –What was the formula again?

Types of Autotrophs Photoautotrophs- capture energy from sunlight and convert it to carbohydrates –Plants, algae, cyanobacteria Chemoautotrophs- capture energy from heat and inorganic compounds and convert it to carbohydrates –Archaebacteria living in deep sea vents

Autotrophs/Producers- –Some bacteria in extreme environments capture energy from inorganic compounds by chemosynthesis

Section 4

13.4 Food Chains And Food Webs TEKS 11C, 12,C KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.

13.4 Food Chains And Food Webs TEKS 11C, 12,C A food chain is a model that shows a sequence of feeding relationships. A food chain links species by their feeding relationships. A food chain follows the connection between one producer and a single chain of consumers within an ecosystem. DESERT COTTONTAILGRAMA GRASSHARRIS’S HAWK

13.4 Food Chains And Food Webs TEKS 11C, 12,C Specialists are consumers that primarily eat one specific organism or a very small number of organisms. Generalists are consumers that have a varying diet.

Heterotrophs/Consumers Organisms that eat OR absorb food to obtain energy

Herbivores Eat only plant life ex. cows, deer, insects

Carnivores- Feed on other consumers Ex: snakes, dogs, anteaters

Omnivores Eat both producers and other consumers Ex: humans, bears, crows

Detritivores and Scavengers: Feed on dead materials Ex: mites, earthworms, crabs

Decomposers Break down organic matter and return it to the earth as inorganic matter Ex: bacteria, fungi, fungus-like protists

Detritivorevs.Decomposer Break down dead organic materialsBreak down dead organic materials Only break down some moleculesOnly break down some molecules Break down dead organic materialsBreak down dead organic materials Can break down more complex moleculesCan break down more complex molecules Break down matter more fullyBreak down matter more fully

13.4 Food Chains And Food Webs TEKS 11C, 12,C Consumers are not all alike. –Herbivores eat only plants. –Carnivores eat only animals. –Omnivores eat both plants and animals. –Detritivores eat dead organic matter. –Decomposers are detritivores that break down organic matter into simpler compounds. carnivore decomposer

13.4 Food Chains And Food Webs TEKS 11C, 12,C Trophic levels are the nourishment levels in a food chain. –Primary consumers are herbivores that eat producers. –Secondary consumers are carnivores that eat herbivores. –Tertiary consumers are carnivores that eat secondary consumers. –Omnivores, such as humans that eat both plants and animals, may be listed at different trophic levels in different food chains.

13.4 Food Chains And Food Webs TEKS 11C, 12,C A food web shows a complex network of feeding relationships. An organism may have multiple feeding relationships in an ecosystem. A food web emphasizes complicated feeding relationships and energy flow in an ecosystem.

Producer Primary consumer Secondary consumer Tertiary consumer Put this one in your notes

Food Webs Link together several food chains within the same ecosystem.

Purpose of food webs and chains: Show how energy flows in an ecosystemShow how energy flows in an ecosystem Direction of the arrow is the direction of the flow of energy- do NOT mix this up!Direction of the arrow is the direction of the flow of energy- do NOT mix this up!

Energy Flow Energy flows in one direction through an ecosystem: Sun  Producers  Consumers  Decomposers Along the way, some energy is “lost” as heat (thermal energy)

What do you mean “lost as heat”? Energy cannot be created or destroyed, only converted from one form to another Light energy is converted to chemical energy stored in food (during photosynthesis) –Is all of the energy this plant makes available to the organism that eats it?

What do you mean “lost as heat”? No! The plant USES some of it to grow, to reproduce, to help make food, etc. Remember back to biochemistry, what happens when we break chemical bonds? –Energy is released as HEAT –Hence through a food chain, much of the energy is lost to the environment as heat.

Energy from the sun enters the first trophic level

Energy goes from the Producers to the first level consumers But how much energy? ONLY 10% of the total energy available goes to the next level

What happens to the other 90%? It’s used for life processes or lost to the atmosphere as heat (thermal energy)

Section 5 Biogeochemical Cycles

Biogeochemical Cycles While energy is transferred in one direction in an ecosystem, matter is cycled through the ecosystem in the biogeochemical cycles

Biogeochemical Cycles Water cycle- how water moves through the air, land, and organisms –Evaporation- water  vapor from surface of bodies of water –Transpiration- water  vapor from plants –Condensation- vapor  water in clouds

Biogeochemical Cycles Water cycle- how water moves through the air, land, and organisms –Precipitation- clouds become too full and rain, snow, etc. fall to the earth –Runoff- water collects into bodies of water –Infiltration/Seepage- water from the surface sinks into ground water storage

13.5 Cycling of Matter TEKS 11C, 12E Water cycles through the environment. The hydrologic, or water, cycle is the circular pathway of water on Earth. Organisms all have bodies made mostly of water. precipitation condensation transpiration evaporation water storage in ocean surface runoff lake groundwater seepage

13.5 Cycling of Matter TEKS 11C, 12E fossil fuels photosynthesis carbon dioxide dissolved in water decomposition of organisms respiration carbon dioxide in air photosynthesis combustion respiration Carbon is the building block of life. –The carbon cycle moves carbon from the atmosphere, through the food web, and back to the atmosphere. –Carbon is emitted during the burning of fossil fuels. –Some carbon is stored for long periods of time in areas called carbon sinks.

13.5 Cycling of Matter TEKS 11C, 12E nitrogen in atmosphere animals denitrifying bacteria nitrifying bacteria nitrifying bacteria ammonium ammonification decomposers plant nitrogen-fixing bacteria in soil nitrogen-fixing bacteria in roots nitrates nitrites The nitrogen cycle mostly takes place underground. –Some bacteria convert gaseous nitrogen into ammonia through a process called nitrogen fixation. –Some nitrogen-fixing bacteria live in nodules on the roots of plants; others live freely in soil.

13.5 Cycling of Matter TEKS 11C, 12E –Ammonia released into the soil is transformed into ammonium. nitrogen in atmosphere animals denitrifying bacteria nitrifying bacteria nitrifying bacteria ammonium ammonification decomposers plant nitrogen-fixing bacteria in soil nitrogen-fixing bacteria in roots nitrates nitrites –Nitrifying bacteria change the ammonium into nitrate. –Nitrogen moves through the food web and returns to the soil during decomposition.

Biogeochemical Cycles Nitrogen Cycle: -Nitrogen fixation- bacteria take nitrogen (N 2 ) from the atmosphere and change it into a form that plants can take up from the soil called ammonium (NH 4 ). -Nitrification- ammonium not taken up by plants are converted to nitrates and nitrites by bacteria which other plants can take up

Biogeochemical Cycles Nitrogen Cycle: -Consumers then eat and take in N in order to make proteins. -Dead organisms can return N to the soil or to the atmosphere with the help of bacteria -Denitrification- bacteria can turn the ammonium back to atmospheric nitrogen

13.5 Cycling of Matter TEKS 11C, 12E geologic uplifting rain weathering of phosphate from rocks runoff sedimentation forms new rocks leaching phosphate in solution animals plants decomposers phosphate in soil The phosphorus cycle takes place at and below ground level. –Phosphate is released by the weathering of rocks. –Phosphorus moves through the food web and returns to the soil during decomposition. – Phosphorus leaches into groundwater from the soil and is locked in sediments. – Both mining and agriculture add phosphorus into the environment.

Nutrient Limitations An ecosystem needs a particular amount of each nutrient to thrive. A single nutrient can limit its success. An excess of a particular nutrient can cause over production of algae and plant growth

Human Effects on Biogeochemical Cycles Carbon- burning fossil fuels releases previously isolated carbon back to the atmosphere Nitrogen and Phosphorus- we add fertilizers to assist crop growth and much of it gets washed away into rivers, lakes and oceans

Eutrophication- overgrowth of photosynthetic organisms in a body of water due to an excess of nitrates and phoshates from urban or agricultural runoff In oceansIn lakes

Eutrophication- overgrowth of photosynthetic organisms in a body of water due to an excess of nitrates and phoshates from urban or agricultural runoff In estuaries Can choke the waters of gas exchange

Section 6

Ecological Pyramids The direction of energy flow through the trophic levels can be shown through food chains and food webs. To show relative amounts of matter and energy per trophic level, we can use a pyramid

13.6 Pyramid Models TEKS 12C energy transferred energy lost An energy pyramid shows the distribution of energy among trophic levels. Energy pyramids compare energy used by producers and other organisms on trophic levels. Between each tier of an energy pyramid, up to 90 percent of the energy is lost into the atmosphere as heat. Only 10 percent of the energy at each tier is transferred from one trophic level to the next.

If 5600 kCal were available at the producer level, how much would be available at each of the other trophic levels?

5.6 kCal 560 kCal 56 kCal 5600 kCal 5600 kCal x 10% = 560 kCal 560 kCal x 10% = 56 kCal 56 kCal x 10% = 5.6 kCal

13.6 Pyramid Models TEKS 12C Other pyramid models illustrate an ecosystem’s biomass and distribution of organisms. Biomass is a measure of the total dry mass of organisms in a given area. tertiary consumers secondary consumers primary consumers producers 75 g/m2 150g/m2 675g/m2 2000g/m2 producers 2000g/m2

13.6 Pyramid Models TEKS 12C A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers secondary consumers primary consumers producers ,000 5,000,000 producers A vast number of producers are required to support even a few top level consumers.