Environmental Science Chp 3 Notes: Matter, Energy, and Life

Ecology

The scientific study of the relationship between organisms and their environment

• The core of the study of ecology is about how matter and energy are exchanged between organisms and their surroundings

Matter

anything that has mass and takes up space

3 States of Matter:

• Solid

• Liquid

• Gas

Matter is neither…

created nor destroyed but rather recycled over and over

Conservation of matter

The idea that matter cannot be destroyed but is simply transformed from one form to another

What are elements composed of?

Atoms

Atoms

smallest particles exhibiting characteristics of the element

What are atoms composed of?

• Protons (+)

• Neutrons

• Electrons (-)

  • Protons and neutrons are in the nucleus; electrons orbit.

Atomic numbers

number of protons

Isotope

forms of an element differing in atomic mass because they have different numbers of neutrons

Ions

atoms that contain more or fewer electrons than protons and therefore have a positive or negative charge

• Anions have a negative charge

• Cations have a positive charge

Acids

substances that release hydrogen ions in water

Bases

substances that readily bond with hydrogen ions

• 0 to 7 is acidic / 7 is neutral / 8 to 14 is basic

• pH scale: logarithmic; each step is 10X

Energy

ability to do work

Kinetic

energy in moving objects

Potential

stored energy

Chemical Energy

stored in food or fossil fuels

Heat

• Energy that can be transferred between objects of different temperature.

• When a substance absorbs heat, the motion of its molecules increases and it may change state

Thermodynamics

Energy must be supplied (from the sun) to keep biological processes running, because as it flows through the various biological processes, it becomes dissipated

First Law of Thermodynamics

Energy is neither created nor destroyed

Second Law of Thermodynamics

With each successive energy transfer, less energy is available to perform work

• Entropy (disorder) increases

Solar energy is essential for (2) reasons:

• Warmth - Most organisms can exist only in a relatively narrow temperature range

• Photosynthesis in plants

Energy for life

• solar radiation reaching the earth’s surface, about 10% is ultraviolet, 45% is visible, and 45% is infrared

• Most of energy is absorbed by land or water, or reflected back into space

• Only about 1-2% of the sunlight falling on plants is captured for photosynthesis

Photosynthesis

• Occurs in chloroplasts within plant cells

• 6H20+6CO2 + solar energy = C6H12O6+6O2

• Glucose serves as primary fuel for all metabolic processes

• Captures energy

Cellular Respiration: Function

Releases energy

• splits carbon and hydrogen atoms from sugar and recombines them with oxygen to re-create carbon dioxide and water

• opposite of photosynthesis

• This is how animals get all their energy, you need to breathe is to supply this pathway with oxygen

• C6H12O6 + 6O2 = 6H2O +6CO2 + energy

Species

all organisms of the same kind that are genetically similar enough to breed in nature and produce live, fertile offspring

Population

all members of a species living in a given area at the same time

Biological Community

all of the populations of organisms living and interacting in a particular area

Ecosystem

biological community and its physical environment

• The physical environment includes non-living factors such as climate, water, minerals, etc.

Food Chains and Food Webs: Producers

Photosynthesis is at the base of all ecosystems so photosynthesizers (usually plants) are usually called this

Productivity

the amount of biomass produced in a given area in a given period of time

Primary Productivity

Photosynthesis because it is basic to all other growth in an ecosystem

Secondary productivity

manufacture of biomass by organisms that eat plants

Food Chain

linked feeding series

Food Web

Most consumers have multiple food sources

Trophic level

An organism’s feeding status in a food web.

Producer Level

Plants

Consumer

animals

Primary consumers

animals that eat plants

secondary and tertiary consumers

animals that other animals

Omnivores

eat both plants and animals

Herbivores

Plants, deer

Carnivores

meat, wolves

Omnivores

plants, meats: bears

Scavengers

carcasses, crows

Detritivores

debris, ants

Decomposers

all, bacteria

Ecological Pyramids

• If the organisms at various trophic levels are arranged diagrammatically, they form a pyramid with many more producers than consumers

• Second Law of Thermodynamics means energy is lost at each level of the pyramid

  • Energy is lost as heat in metabolic processes