Ch 3 The Biosphere Studying Our Living Planet

Ch 3: The Biosphere

Studying Our Living Planet l Biosphere: all life on Earth and all parts of the Earth in which life exists l Eco = oikos, meaning house l Ecology: study of interactions among & between living organisms and their physical environment

Levels of Organization l Ecologists have organized the interactions an organism takes part in into different levels according to complexity.

Ecological Levels of Organization

1 st Level of Organization l Organism/Individual: A living that is made of cells, uses energy, reproduces, responds, grows, and develops—is part of a species l Species: group of similar organisms that can breed & produce fertile offspring

2 nd Level of Organization l Population: A group of organisms, all of the same species, which interbreed and live in the same place at the same time.

3 rd Level of Organization l Biological Community: All of the populations of different species that live in the same place at the same time.

4 th Level of Organization l Ecosystem: Populations of organisms that interact with each other and with the environment of a given area.

5 th level of Organization -Biomes are a group of ecosystems with similar climates and typical organisms.

6 th Level: The Biosphere l Life is found in air, on land, and in fresh and salt water. l The BIOSPHERE is the portion of Earth that supports living things.

Biotic and Abiotic Factors l Biotic factor – living components of the environment with which an organism may interact; all of the biological influences on organisms --Ex: Plants, Animals, Fungi, Protists, Bacteria l Abiotic factor – any nonliving part of the environment that affects the organism --Ex: Sunlight, heat, precipitation, humidity, wind, water currents, soil type, etc.

Abiotic or Biotic? Biotic

Abiotic or Biotic? Abiotic

Abiotic or Biotic? Abiotic

Abiotic or Biotic? Biotic

Energy, Producers, & Consumers l Living systems operate by using energy l Need energy for: growth, reproduction, metabolism, etc. l Organisms can only use energy from other sources l Where do you get your energy from? ? l Where does the energy in food come from? ? ?

What is our Planet’s Energy Source? l. For most life on Earth, sunlight is the ultimate energy source l. For some organisms energy stored in chemicals in rocks, soil, etc. , serves as their primary energy source

Primary Producers (Autotrophs) l • • Organisms that produce their own food supply Cells of most autotrophs contain chlorophyll & can use energy directly from the sun Ex: plants, attached algae, freefloating algae (phytoplankton), & some bacteria May be photoautotrophs using light energy (e. g. plants) May be chemoautotrophs using chemical energy (e. g. some bacteria)

Photosynthesis l Chemical reaction where producers use water and carbon dioxide to store the sun’s energy as glucose. 6 H 2 O + 6 CO 2 + Sun C 6 H 12 O 6 + 6 O 2

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Chemosynthesis l Chemical reaction where producers use chemicals and carbon dioxide to store energy as glucose.

Consumers (Heterotrophs) l Eat other organisms to obtain energy. Ex: animals, fungi, protists, & many bacteria l Herbivores --Eat only plant products (leaves, roots, seeds, or fruits) --Ex: Cows, caterpillars, deer l Carnivores --Eat only other animals --Ex: Snakes, dogs, cats, otters l Omnivores --Eat plant products & animals --Ex: Humans, bears, pigs, raccoons l Scavengers --Eat carcasses of other animals killed by predators or died of natural causes --Ex: Vultures l Decomposers --`feed’ by chemically breaking down organic matter; produces detritus (small pieces of dead & decaying plant & animal remains) --Ex: Bacteria & fungi l Detritivores --Consume detritus & the decomposers that live on/in detritus --Ex: Earthworms, mites, snails, shrimp, crabs

Feeding Relationships Energy flows through an ecosystem in one direction: from producers to various levels of consumers l Food Chain l Series of steps in which organisms transfer energy by eating & being eaten l Food Web l More realistic path through an ecosystem—made of many food chains (because organisms may eat more than one kind of food!)

Food Webs l Are interconnected food chains l They show the feeding relationships in an ecosystem

Food Chain 1 st Order Consumer Producer (trapped sunlight & stored food) 2 nd Order Consumer 3 rd Order Consumer 4 th Order Consumer

Trophic Levels l Levels through which energy flows in an ecosystem l Each step taken in a food chain or web is called a trophic level l 1 st level: Primary producers l 2 nd level: Primary consumers l 3 rd level: Secondary consumers l 4 th level: Tertiary consumers

Food Chains Show Available Energy

What happens to the energy? l Most of the energy the primary consumer gets from the producer is used by the consumer l Some of the energy moves into the atmosphere as heat. l Rule of 10: Only about 10% of energy is transferred from one trophic level to the next. The rest is used for life functions (growth, reproduction, etc)! l Example: l It takes 100 kgs of plant materials (producers) to support 10 kgs of herbivores l It takes 10 kgs of herbivores to support 1 kg of 1 st level predator

Ecological Pyramids Another way of showing the relative amount of energy or matter contained in each trophic level l 3 different types: --Energy --Biomass --Numbers l

Ecological Pyramids Show Energy Pyramids: Amount of available energy at each trophic level l Only 10% of energy is transferred from one level to the next. l Biomass Pyramids: l Amount of living organic matter available at each trophic level (grams/kg) Numbers Pyramids: l Number of individual organisms at each trophic level (population size) 30

Ecosystem Recycling: Cycles of Matter l All ecosystems must have cycles of systems to reuse raw materials (there is not an infinite amount of resources!!!) l Matter is recycled within & between ecosystems l Biogeochemical Cycles: closed loops that allow matter to be recycled through biological, geological, & chemical (physical) processes l Water Cycle l Carbon Cycle l Nitrogen Cycle l Phosphorus Cycle

Water Cycle • • • Evaporation Transpiration Precipitation Runoff Groundwater

Steps of the Water Cycle Water vapor in the air condenses and falls as rain or snow. 2 A. Some rain/snow seeps into soil and becomes part of groundwater. 2 B. Most rain/snow falls into the ocean. 3 A. Water is heated by the sun and evaporates. 3 B. Plants absorb water that is in the ground. 4. After going through the plant, the sun and wind pulls water out by evaporation – process called transpiration. 1.

Nitrogen/Phosphorus Cycle • Found in atmosphere, runoff, fertilizersdue to decomposition • Nitrogen & phosphorus are used in the synthesis of amino acids (proteins), nucleic acids (DNA), & energy molecules (ATP) • Nitrogen/Phosphorus fixing (converting): done by bacteria/fungi; change nitrogen/phosphorus compounds into a usable form for plants • Nitrogen/Phosphorus in soil is then absorbed by plants and becomes part of the plant’s tissues • Plants are consumed by herbivores or omnivores & these organisms are then consumed by another consumer or decomposed of when they die

Carbon Cycle • • • Combustion Photosynthesis Respiration Decomposition Fossil fuels

Steps of the Carbon Cycle CO 2 in the air is used by producers for photosynthesis. They become part of the producers in the form of sugar. 2 A. Respiration – most organisms (plants, animals, etc) breathe in O 2 created by producers. They breathe out CO 2. 2 B. Combustion – burning of fossil fuels increase CO 2 in the air. 2 C. Decomposition – Decay of dead organic wastes by bacteria/fungi create CO 2. 1.

l Primary Nutrient Limitation Productivity: rate at which organic material is produced by autotrophic organisms l With ample sunlight & water, primary productivity may be limited by the nutrients available l Limiting nutrient: nutrient whose supply limits productivity l Limitations can occur in soil or in aquatic habitats