chapter 1 biology exploring life. chapter 1: biology: the study of life what is life?
TRANSCRIPT
Chapter 1
Biology Exploring Life
Chapter 1: Biology: the study of life
What is Life?
Section 1.1Levels of Organization
BIOSPHERE ECOSYSTEM COMMUNITY
POPULATION ORGANISM
ORGAN SYSTEM
ORGANS TISSUES
CELL ORGANELLE MOLECULE
ATOM
Cover the broad scope of biology
Section 1.2 Living organisms and their environment for interconnecting webs
Food Web Producers Consumers Decomposer
Dynamic of an Ecosystem
Energy Flow Recycling
chemical nutrients
Section 1.3 Cells are the structural and functional units of life
Perform all activities required for lifeProkaryotic cell
Simpler, smallEukaryotic cell
More complex largerNucleus
(contains DNA)
Eukar yotic cell
Prokar yotic cell
DNA(no nucleus)
Organelles
25,0
00
1.4 The unity of life: All living things have common characteristics
All living things have common characteristics DNA Order Regulation
homeostasis Growth and Development Energy utilization
metabolism Response to environment Reproduction Evolution
mutation
1.5 Diversity of Life
Extent of diversity has led to classification schemes
K-P-C-O-F-G-S Six Kingdoms
Eubacteria Archeabacteria Protista-one-celled organisms Fungi-mold and mushrooms Plantae- multicellular plants Animalia; multicellular animals
1.6 Evolution explains the unity and diversity of life
Charles Darwin Artificial
selection
Natural Selection Observation # 1
Individual variation Observation # 2
Overproduction and Competition
INFERENCE Unequal reproductive success Those with heritable traits best fit the environment
will survive and reproduce
Accumulation of favorable variation in a population over time
The Galapagos Islands
Finches Beak size
1
2
3
Populations with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors
Teddy Graham Lab
1.7 The Nature of Science
Science is way of knowing Seeks causes for natural phenomena
Discovery Science Inductive reasoning
Hypothesis Based ScienceDeductive reasoning
1.8 The Scientific Method
Make an observation Ask a Question Make a Hypothesis using all known information Predict what the outcome would be if the hypothesis is
valid Test the hypothesis by experiments, models, and
observations Repeat the tests for consistency Examine alternative hypotheses in the same manner Report objectively on the tests and conclusions
Scientific Method
Independent VariableThe variable you have control over
Dependent VariableChanges in response to the independent
variableControlled Variables
Remain constant so results of the experiment are valid
What is a scientific theory?
A theory is a related set of hypothesis that for a broad-ranging explanation of many phenomena
Theories are rejected and accepted on the basis of tests and are subject to revision
Scientists must be content with relative certainty the theory is valid
Theories can change if new scientific evidence is provided
Does Science have Limits?
It is limited to questions that can be tested
Subjective questions cannot be addressed
Science may be controversial when it offers an explanation for something previously thought the be supernatural
Chapter 2
The Chemical Basis of Life
Nature’s Chemical Language The rattlebox moth
Produces chemicals important for mating and defense
2.1-2.2 The human body, as all of nature, is made of chemical elements.
element: cannot be broken down to other substances by ordinary chemical means
Most common in human body (96%)Oxygen (O)Carbon (C)Hydrogen (H)Nitrogen (N)
Trace element: small amount is essential
2.3 Elements can combine to form compounds
Compound: a substance containing two or more elements in a fixed ratioMore common than pure elements
ex. Vitamin A, Proteins
Sodium Chlorine Sodium Chloride
Trace elements are common additives to food and water
Dietary deficiencies in trace elements Can cause various physiological conditions
Figure 2.2A
2.4 Atoms consist of protons, neutrons, and electrons
Atom: the smallest unit of matter that still retains the properties of an element
Three subatomic particles
Protons (p+) atomic nucleus single positive charge
Neutrons part of the atomic nucleus they have no charge
Electrons (e-) have a negative charge; they circle around the nucleus # of e = # of p
Atomic Number
Defines the elementequal to the number of of protonsIs equal to the number of electrons in a
neutral atomAlways the whole number
Mass number: equal to the number of protons plus the number of neutrons in its nucleus
Atomic Mass
Is equal to the number of protons and neutrons in the nucleus of the atom (mass number)
May not be a whole number on the periodic table
In biology you may round the atomic mass to a whole number
2.5 Radioactive isotopes can help or harm us
Isotopes: different forms of atoms Atoms with the same number of protons
and electrons but a different number of neutrons
Radioactive isotopes Nucleus decays spontaneously giving off
particles of energy Research/Medicine
Radioactive tracers Dangers
Damage molecules (DNA)
2.6 Electron arrangement determines the chemical properties of an atom
electron shells: certain energy levels where electrons occur Each shell holds up to a certain # of e-
the # of e- in the outermost energy level determines the chemical properties of an atom
(how it will bond w/other atoms)
Chemical bond: attractions holding atoms together
Ion – charged atom
Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)
Transferof electron
Protons +11Electrons -11Charge 0
Protons +17Electrons -17Charge 0
Protons +11Electrons -10Charge +1
Protons +17Electrons -18Charge -1
Section 2-1
Figure 2-3 Ionic Bonding
Ionic bonding
Transfer of Electrons from one atom to another
Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)
Transferof electron
Protons +11Electrons -11Charge 0
Protons +17Electrons -17Charge 0
Protons +11Electrons -10Charge +1
Protons +17Electrons -18Charge -1
Section 2-1
Figure 2-3 Ionic Bonding
Transfer of electrons
Covalent Bond
Sharing of electronsElectrons are not completely transferred
to another atom
Rules for drawing covalent bonded molecules
2 electrons 1 bond 1 line You can form more than one bond between
atoms Carbon 4 bonds Oxygen always has 2 bonds and 2 lone pairs Hydrogen always has 1 bond Nitrogen has 4 bonds or 3 bonds and a lone
pair of electron
some organic molecules
Methane Acetylene Butadiene Benzene Isooctane
Section 2-3
Figure 2-11 Carbon Compounds
Go to Section:
2.9 Unequal electron sharing creates polar molecules
Atoms in a covalent bond are in a constant tug-of-war for the shared electrons
Electronegativity: an atom’s attraction for its electrons, including shared electrons
Nonpolar: atoms exert an equal pull on the electrons
Polar: unequal sharing of electrons
Waterpolar molecule
Hydrogen Bonding
In a hydrogen bond, an atom or molecule interacts weakly with a hydrogen atom already taking part in a polar covalent bond
Hydrogen Bonds
Hydrogen bonds form any time a hydrogen atom is bonded to an F, O, N
They are weak bonds between to molecules
Hydrogen bonds make liquid water cohesive
Properties of water
Water is polar Hydrophilic; water
loving Hydrophobic; water
hating Cohesive properties
due to hydrogen bonding
Universal solvent
2.12 Water’s hydrogen bonds moderate temp.
Heat The amount of energy associated with the movement of
atoms and molecules in the body
Warming Disrupts (H) bonds then speeds up molecules Store large amounts of heat while warming a few degrees
Cooling Heat energy is released when (H) bonds form, slowing
the cooling process
2.13 Ice is less dense than liquid
2.14 Water is the solvent of life
Solution: liquid consisting of a uniform mixture of two or more substances
Solvent: dissolving agentSolute: substance that is dissolved
Water as a Solvent
Cl-
Water
Cl-
Na+
Water
Na+
Section 2-2
Figure 2-9 NaCI Solution
Go to Section:
NaCl as the solute
Acids, Bases and Salts
Acid is a proton donor (H+), have a pH less than 7
Base is an proton acceptor; has a pH greater than 7
A salt is formed when and acid reacts with a base
Buffer is a solution that is resistance to pH change
The pH scale
pH is a measure of the H+ concentration in a solution
The greater the H+ the lower the pH