Chapter 3: Matter, Energy, and Life
Define matter, atoms, moleculesDefine energy and energy flowDefine basic fundamentals of Ecology
I. From Atoms to Cells
A. General Information 1. Ecology – The study of the
relationships between organisms and their environment Studies the life histories, distributions, and
behaviors of individual species Studies the structure and function of
naturals systems at the level of populations, communities, ecosystems, and landscapes
I. From Atoms to Cells A. General information
2. Holistic approach to ecology Uses systems to study interactions Observe the interconnected nature of
systems and organisms within B. Atoms, Molecules, and Compounds
1. Matter – everything that has mass and takes up space It exists in 3 distinct states
Solid, liquid, and gas
I. From Atoms to Cells B. Atoms, Molecules, and Compounds
Atoms have unique chemical forms called Elements Cannot be broken down into simpler forms
by ordinary chemical reactions 4 elements make up 96% of the mass of all
organisms The elements are O, C, H, N
2. Atoms - the smallest particles that exhibit the characteristics of the element Composed of electrons, protons, and
neutrons
I. From Atoms to Cells Atomic number is the number of protons
and is used to form the periodic table The number of neutrons may differ creating
isotopes Atoms can join together to form molecules
Molecules are any two atoms joined together Compounds are molecules created with
different types of atoms Chemical bonds hold atoms together
2 major types of bonds are ionic and covalent
I. From Atoms to Cells 3. Ions
Make up acids and bases Unequal numbers of electrons and protons
Positive ions form acids (give up electrons readily, i.e. electron donors)
Negative ions form bases (can bond easily with hydrogen ions, i.e. electron acceptors)
The number of free hydrogen (hydronium) ions and hydroxide ions in solution is used to create the pH scale
I. From Atoms to Cells 4. Organic Compounds
Some elements are used, by organisms, in abundance
Some elements are used, by organisms, in trace amounts
Any compound containing carbon is called an organic compound
4 major categories of organic compounds Carbohydrates
Sugars, instant energy
I. From Atoms to Cells Lipids
Fats and oils Also called hydrocarbons Long chains of carbon with 2 Hydrogen
atoms attached Proteins
Made up of amino acids Composed of amine group and carboxyl
group
I. From Atoms to Cells Nucleic acids
Made up of deoxyribose, phosphate group and a nitrogen base
DNA
5. Cells Fundamental units of life Some are single-celled
Bacteria, algae, protozoa Some are multi-celled
Plants, animals, fungi
I. From Atoms to Cells
5. Cells (cont.) Chemical reactions occur because of
enzymes Otherwise cells would burn up due to the
combustion of metabolism Energy transfer is called metabolism in
cells For example, sugar to ATP
II. Energy and Matter 1. General Information
Essential constituents of all living organisms
Energy provides the force to hold structures, tear apart structures, and move materials
2. Energy Types and Quantities Energy is defined as the “ability to do
work” Kinetic Energy – is the energy of movement
II. Energy and Matter Potential Energy – is stored energy, the
energy of position Chemical Energy – is the energy stored in
the food you eat, energy of chemical bonds Measured as Joules (physics), BTU’s
(propane), and Calories (food) Power is the rate of doing work Heat describes the total energy not used
in the movement of an object; lost energy
II. Energy and Matter Temperature is the speed of motion of
an atom 3. Conservation of Matter
Matter, like energy, is neither created nor destroyed
Called the Conservation of Matter Matter is transformed and combined
II. Energy and Matter
4. Thermodynamics and Energy Transfers Organisms use gases, water and
nutrients Metabolism – waste products are returned
to the environment in a different form (by-products)
Energy is not recycled (in the biosphere) Must provide energy from an external
source
II. Energy and Matter Energy has a one-way path that
eventually ends up in a low-temperature sink
First Law of Thermodynamics Energy is conserved Cannot be created nor destroyed, only
transferred from one form to another form Second law of Thermodynamics
As energy is transferred or transformed, there is less energy to do work Energy is ‘lost’ to the environment
II. Energy and Matter Recognizes a tendency of all natural
systems to go from a state of order toward a state of increasing disorder Entropy – “Entropy Rules!” Also called the ‘Chaos Theory’
For example: Life to Death
III. Energy for Life
1. Solar Energy: Warmth and Light Organisms survive at different
temperature ranges Low temps affect metabolism negatively,
not enough energy produced to survive High temps break down molecules
rendering them non-functional Photosynthesis converts sunlight into
organic compounds that can be used as energy
III. Energy for Life
1. Solar Energy: Warmth and Light Cellular respiration converts the organic
compounds of photosynthesis into ATP
IV. From Species to Ecosystems 1. Populations, Communities and
Ecosystems Species are all of the organisms that are
genetically similar enough to reproduce viable offspring
Populations consist of all of the members of a species living in a given area at a given time Extinctions can be large scale (complete)
and small scale (local)
IV. From Species to Ecosystems 1. Populations, Communities and
Ecosystems A community is all of the populations of
organisms living and interacting in a particular area
An ecosystem is the biological community and its physical environment
Boundaries between communities and ecosystems may be difficult, but must occur
Ecosystems are separated based on communities, climate, and productivity of the communities
IV. From Species to Ecosystems 2. Food Chains, Webs, and Trophic Levels
Primary Productivity is the amount of biomass produced in a given area Higher productivity ecosystems – TRF, TSF, and
Wetlands Lower productivity ecosystems – Deserts, Tundra
Net Primary Productivity includes decomposition and can change the scale of productivity TRF is no longer a high productivity ecosystem
IV. From Species to Ecosystems 2. Food Chains, Webs, and Trophic Levels
Consumption of plants is considered Secondary productivity
Food Chains are a linking of feeding series between organisms For example, Grass Grasshopper Frog Or Grass Cow Man (steak, yeah baby!) In communities, consumers have primary food
sources Will eat that food source first Some consumers have secondary food sources
Don’t compete as well for this food source
Food Chain
Food Web
IV. From Species to Ecosystems 2. Food Chains, Webs, and Trophic
Levels Some consumers are opportunistic
Stumble on food (not the norm) Will eat primary food source, but will anything it
happens across Typically are called omnivore Examples are bears, raccoons
A Trophic Level is an organisms ‘feeding’ status Producers are the first trophic level (autotroph)
IV. From Species to Ecosystems Primary consumers are the second trophic
level (herbivore) Secondary consumers are the third trophic
level (carnivore) There is energy ‘loss’ at each trophic level
Typically the consumer receives 1/10th of the energy… 9/10th is lost
Most food chains are 3 trophic levels, some are 4, very few are 5 Due to the energy loss during each
consumption
IV. From Species to Ecosystems Tertiary consumers are either top
carnivores or scavengers (third, fourth, or fifth trophic level)
Detritovores consume leaf litter, debris, and dung (third, fourth, or fifth trophic level)
Decomposers finish the break-down process of materials (third, fourth, or fifth trophic level) Turns the material into very elemental
forms
IV. From Species to Ecosystems
3. Ecological Pyramids Number of organisms (by percent) in
each trophic level Can be used to describe the available
energy for habitats, communities, or ecosystems
V. Material Cycles and Life Processes
1. The Carbon Cycle Has 2 purposes for organisms
Structural component of organic molecules Energy storage in the chemical bonds
Starts with CO2 intake by producers Carbon is incorporated into sugar Sugar is burned in all organisms through
Cellular Respiration, releasing CO2 into the ecosystem
V. Material Cycles and Life Processes
1. The Carbon Cycle (cont.) Some carbon is lost to ‘carbon sinks’
Ex. Coal, Oil, and Trees Carbon is not released until combustion Calcium Carbonate (CaCO3) is incorporated
into shells of organisms Very difficult to break down, especially in
anoxic conditions at the bottom of lakes and oceans
V. Material Cycles and Life Processes
2. The Nitrogen Cycle Organisms can not exist without organic
compounds comprised of Nitrogen Ex. Proteins, nucleic acids, amino acids, etc.
Inorganic forms of Nitrogen are utilized by plants to form organic compounds
Nitrogen is the most abundant element in the atmosphere, but it is unusable as N2
V. Material Cycles and Life Processes
2. The Nitrogen Cycle (cont.) The nitrogen cycle provides usable N for
plants Nitrogen-fixing bacteria turn the N2 into
usable N for plants (NH3 : ammonia) Nitrite forming bacteria change NH3 into NO2
(nitrite) Nitrate forming bacteria converts NO2 into
NO3 (nitrate) NO3 is used by the plants
V. Material Cycles and Life Processes
2. The Nitrogen Cycle (cont.) Plants convert NO3 into NH4 (ammonium) NH4 is used to create amino acids Nitrogen re-enters the system when
organisms die through decomposition Nitrogen, also, re-enters the system
through metabolic waste (uric acid) Urination dumps nitrogen (called pulses) into
streams, rivers, and soil Bacteria consume and turn the waste into NH3
Root Nodules containing N-fixing bacteria
N-fixing bacteria
V. Material Cycles and Life Processes
3. The Phosphorus Cycle Phosphorus is used by organisms for
energy transfer processes Major component of fertilizers Begins with phosphorus leaching from
rocks into groundwater Inorganic phosphorus is absorbed by
producers Turned into organic compounds
V. Material Cycles and Life Processes
3. The Phosphorus Cycle Reintroduced to the environment
through decomposition of organic material
V. Material Cycles and Life Processes
4. The Sulfur (Sulphur) Cycle Used in proteins Determine acidity of rainfall, surface
water, and soil Most is in the form of rocks and minerals
Iron disulfide (FeS2), calcium sulfate (CaSO4)
Inorganic sulfur is released into the atmosphere as SO2 and SO4 (Sulfate)
V. Material Cycles and Life Processes
4. The Sulfur (Sulphur) Cycle (cont.) Sulfur has many oxidative states
Ex. Hydrogen Sulfide (H2S), Sulfur Dioxide (SO2), Sulfate ion (SO4-), and S (elemental)
Human activities release sulfur Ex. Burning of fossil fuels
Phytoplankton release large quantities of sulfur to the atmosphere (especially during warming trends) DMS SO2 SO4 (DMS is Dimethylsulfide) Increases the earth’s albedo
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