Ecology: Energy and Matter

Introduction to Ecology

• Ecology is the scientific study of interactions among organisms and between organisms and their physical environment.
• Biotic factors are the living parts of the environment.
• Abiotic factors are the nonliving parts of the environment.

Energy and Matter in Ecology

• Understanding energy and matter is critical to the study of ecology.
• Energy flow and matter cycles are two big ideas summarizing the role of energy and matter.
• Energy flows through ecosystems.
• Matter cycles through ecosystems.

Unit 1 Energy and Matter Review

• Photosynthesis stores energy from sunlight in the bonds of glucose molecules, which is chemical energy.
• Cellular respiration releases the chemical energy in the bonds of glucose to create a usable form of energy, ATP.
• Organisms that perform photosynthesis AND cellular respiration are called producers, which can produce and consume their own matter for energy.
• Consumers are organisms that can only perform cellular respiration.
  • Consumers must consume the biological matter of other organisms for energy.
• In an ecosystem, energy flows from the sun, to producers, and then to consumers.
• Energy flows because it is lost as it moves from abiotic to biotic factors in an ecosystem.
• According to the 90-10 rule, 90% of the energy an organism consumes is used for metabolic processes and lost as heat.
• 10% of the energy an organism consumes is stored in their biological tissues.
• Energy is a limiting factor, meaning that factors in an ecosystem that limit the population size of species.
• The availability of energy limits the population size of species.
• Population size decreases as energy flows through higher trophic levels because it is lost as heat.
• Matter that makes up life includes four major macromolecules made up of five major elements.
• The major elements are Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and Phosphorous (P).
• The major macromolecules are carbohydrates, lipids, proteins, and nucleic acids.
• Carbohydrates are made of carbon, hydrogen, and oxygen
  • Monomers of glucose form complex carbohydrates like starch and glycogen.
  • Glucose is the main source of energy for cells.
  • Starch (plants) and glycogen (animals) provide structural support and energy storage.
• Lipids have a structure of carbon, hydrogen, and oxygen
  • Lipids function as long-term energy storage, insulation and protection for organs, and as major components of cell membranes.
• Proteins are made of carbon, hydrogen, oxygen, and nitrogen in long chains of amino acids
  • Proteins are used as enzymes to speed up chemical reactions, used to provide structural support, and provide transport, cell signaling, and immune defense.
• Nucleic Acids (DNA and RNA) are made of carbon, hydrogen, oxygen, nitrogen, and phosphorous.
  • Nucleic Acids are a long chain of double-stranded (DNA) or single-stranded (RNA) nucleotides.
  • Nucleic Acids function to store and transmit genetic information (DNA), contain instructions for building proteins (DNA), and helps in protein synthesis (RNA).
• Producers combine the atoms of inorganic molecules with atoms of glucose to create the major macromolecules. For example, the atoms of glucose combine with the atoms of inorganic nitrogen compounds to create amino acids.
  • Proteins contain the atoms C, H, O, and N.
• Consumers consume the organic matter of other organisms, digest them into simpler molecules, and then synthesize their own organic macromolecules.
• Unlike the one-way flow of energy, matter is recycled within and between ecosystems.
• Decomposers return matter to the environment by consuming the dead and decay matter of life, for example, fungi (mushrooms) and bacteria.
• Photosynthesis and cellular respiration are examples of the cycle of matter in ecosystems.
  • The inputs of photosynthesis are the outputs of cellular respiration.
  • The inputs of cellular respiration are the outputs of photosynthesis.

Cycles of Matter

• Elements of matter pass between the biosphere, atmosphere, hydrosphere, and geosphere in a cyclical manner through biological, geological, and chemical processes.
  • Biosphere includes all living things on Earth.
  • Atmosphere is the layer of gas that surrounds Earth.
  • Hydrosphere includes all water on Earth in any form.
  • Geosphere is the solid part of Earth from surface to core.

The Carbon Cycle

• The carbon cycle has biological, geological, and chemical processes.
• Photosynthesis and cellular respiration are examples of biological processes.
• The formation of fossil fuels is a geological process.
  • Over millions of years, dead organisms get buried and compressed into coal, oil, or natural gas.
• Carbonate formation is a chemical process.
  • Marine organisms use dissolved carbon dioxide to form calcium carbonate shells.
• The burning of fossil fuels (combustion) releases large amounts of carbon dioxide into the atmosphere.

The Coevolution of Life and Earth

• Approximately 4.6 to 3.8 billion years ago, the earth's atmosphere was rich in carbon dioxide (CO2) and water (H₂O) vapor but little to no oxygen (O2).
• Heavy volcanic activity created land mass with no soil, just bare rock, which is know as the geosphere.
• Oceans were forming from condensed water vapor in an environmental stage known as the hydrosphere.
• Early oceans lacked oxygen during this period.
• Cyanobacteria (blue-green algae) began using photosynthesis, which uses carbon dioxide (CO2) and releases oxygen (O2) as a byproduct.
  • Oxygen levels increased slowly in the atmosphere and carbon dioxide decreased in the atmosphere.
• Oxygenate water allows for the development of more complex life as cyanobacteria (blue-green algae) began using photosynthesis, which released oxygen (O2) as in the water.
• Life alters ocean chemistry by absorbing carbon dioxide.
• Microorganisms, fungi, and early plants broke down rock into smaller particles so that decayed organic matter created nutrient-rich soil on the geosphere.
• Ecological succession is the natural process by ecosystems change and develop over time.
  • During ecological succession, the types of plants, animals, and other organisms in an area gradually change as the environment becomes more suitable for different species.

Engineering and Science

• Engineering is problem-solving with a purpose.
• Engineers analyze criteria (what the solution should do) and constraints (what it can't do – like cost or time).
  • Engineers break down complex problems into smaller measurable parts.
• Engineers makes tradeoffs by sometimes choosing between two good options or sacrificing one feature to get another.
• Criteria are rules, goals, or standards for the solution.
• Constraints are what the solution can't do.
  • Criteria being durable and stylish constraints may be cost and weight.
• Breaking down complexity involves turning a large, vague goal into smaller, measurable parts.
  • A big goal is to design a backpack, and a broken down constraint to use recycled materials to make it durable, inexpensive, and stylish.
• It's not always possible to have the perfect solution - but you can make the best decision by weighing tradeoffs.
  • Where a more durable backpack is more expensive and a stylish backpack is less durable.
  • Which criteria are prioritized and which tradeoffs are acceptable depends on design criteria.