consists of all the organisms living in a particular area as well as all the nonliving physical components of the environment with which the organisms interact, such as air, soil, water, and sunlight.
Characterized by the cycling of chemical nutrients from the atmosphere and soil to producers to consumers to decomposers and back to the environment.
- Energy only flows one way through an ecosystem from sun- to producers- to consumers- then exiting
- as heat.
plants and other photosynthetic organisms that provide food for a typical ecosystem
eat other plants and other animals
bateria, fungi, and small animals in the soil that decompose wastes and the remains of dead organisms. Act as recyclers, changing complex matter into simpler mineral nutrients that plants can use.
what you think will happen in the experiment- statement of expected outcome “if…. Then…. “If the battery is dead, then the lights wont come on”
- a proposed explanation for a set of observations. A
- good hypothesis leads to predictions that scientists can test by recording additional observations or by designing experiments.
totality of an organism’s chemical reactions
the steady state of body functioning; a state of equilibrium characterized by a dynamic interplay between outside forces that tend to change an organism’s internal environment and the internal control mechanisms that oppose such changes.
the variable being tested is present.
the variable being tested is absent
the theory that species living today are descendants of ancestral species. “descent with modification”.
is designed to compare an experimental group with a control group. Ideally they will differ in only one factor that the experiment is designed to test
simple and usually much smaller than a eukaryotic cell. Have DNA but no nucleus
subdivided by internal membranes into many different functional compartments, or organelles, including the nucleus that houses the cell’s DNA
Bacteria-consists of prokaryotes, are the most diverse and widespread prokaryotes and are now divided among several kingdoms.
Archaea- many live in extreme environments, also includes multiple kingdoms.
Eukarya- All have nucleus and other internal structures called organelles.
4 divisions of Eukarya
Protista- diverse collection of mostly single celled organisms. Some like algae bake their food by photosynthesis. Some are animal like in that they eat other organisms.
- Plantae- multicellular, plants which produce their own
- food by photosynthesis and have cells with rigid walls made of cellulose.
Fungi- diverse group that includes molds, yeasts, and mushrooms. They are decomposers and help break down the remains of dead organisms and organic wastes.
Animalia- obtain food by ingestion which means they eat other organisms. Most are motile and are made of cells that lack rigid walls.
goal is to apply scientific knowledge for some specific purpose. Technology is driven by necessity.
is much broader in scope than a hypothesis. Explains a great diversity of observations and is supported by a large and usually growing body of evidence. Most continue to generate new hypothesis which can be tested.
Explain how the web of relationships gives an ecosystem its structure
The hierarchy of organization says that with each step upward, new properties emerge as a result of interactions among components of the lower levels.
Describe the seven features that are common to all living organisms
- Order, complex organization
- Regulation, homeostasis of some sort
- Growth and development
- - Energy processing, must take in energy to
- perform activity
- Responds to environment,
- Reproduction, must reproduce their own kind.
- - Evolutionary adaptation, evolving over many
- generations to best suit their environment
Compare prokaryotic and eukaryotic cells
- - Similarities, enclosed by a membrane that regulates
- passage of materials between the cell and its surroundings. Use its DNA as its genetic information.
- Differences- pro, usually much smaller, no nucleus. Eukaryotic, subdivided by internal membranes into different functional compartments, has a nucleus.
that you see or can record that can be used to develop your hypothesis
we are actually testing the factor we are manipulating. Usually prefaced with an “if”
the thing that actually can change in response to the changes in the experimental variable.
steps in the scientific
- Test or experiment
anything that occupies space and has mass, or an object’s weight
indivisible, smallest unit of matter that still retains the properties of an element.
two or more atoms held together by covalent bonds
Element- is a substance that cannot be broken down to other substances by ordinary chemical means.
Proton- subatomic particle with a single positive electrical charge
Neutron- has no electrical charge
atomic number- the unique number of protons in an atom, also the number of electrons unless noted.
Atomic mass- approximately equal to its mass number- sum of its protons and neutrons
Electron shell- energy levels surrounding the nucleus of an atom. Size depends on the amount of electrons orbiting the nucleus.
Chemical bond- when two atoms with incomplete outer shells react, each either shares, donates, or receives out electrons so that both end up with completed outer shells. This helps the atoms stay close together.
Ionic bond- two ions with opposite charges attract each other, when the attraction holds them together its called an ionic bond.
Ions- atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons.
Covalent bond- strong chemical bond where two atoms share one or more pairs of outer shell electrons.
Polar- has an unequal distribution of charges and is slightly negative at the oxygen end of the molecule and slightly positive at each of the two hydrogen ends. H2O is polar.
Nonpolar- when two identical atoms exert an equal pull in the electrons- sharing electrons equally
Electronegativity- an atoms attraction for shared electrons
Hydrogen bond- weak sharing of electrons which happens when molecules are polar, always on the hydrogen, helps structure and orient the molecules because of the charges
Cohesion- tendency of the molecules to stick together- occurs with hydrogen bonding.
Surface tension- measure of how difficult it is to stretch or break the surface of a liquid. Hydrogen bonds give water unusually high surface tension.
Temperature- measures the intensity of heat- the average speed of molecules rather than the total amount of heat energy
Heat- amount of energy associated with the movement of atoms and molecules in a body of matter.
Isotope- an atom of an element that has the same atomic number, but some may differ in mass number
Radioisotope- an atom in which the nucleus decays spontaneously giving off particles and energy.
Chemical reaction- making and breaking of chemical bonds,leading to changes in the composition of matter.
Compound- a substance containing two or more elements in a fixed ratio like table salt- one sodium to one chlorine
Aqueous solutions- solution where water is the solvent
Solution- liquid consisting of a uniform mixture of two or more substances.
Solvent- dissolving agent
Solutes- substance dissolved in the solvent
pH- used to describe how basic or acidic a solution is, each unit is a tenfold change in concentration of hydrogen in the solution.
Acid- a compound that donates hydrogen ions to solutions
Base- compound that accepts hydrogen ions and removes them from solution
Buffer system- minimize shifts in pH, ex: carbonic acid and bicarb in the blood stream
Buffer- substances that minimize changes in pH
What important elements make up the human body?
Calcium for bones and nerve function, phosphorus for bones, potassium for muscle and nerve function, sulfur for proteins, trace elements like iron and others are less than 1% of body weight