Download THE SCOPE OF LIFE The Properties of Life THE SCOPE OF LIFE

9/7/2012
THE SCOPE OF LIFE
The Properties of Life
(a) Order
(b) Regulation
(c) Growth and development (d) Energy utilization
THE SCOPE OF LIFE
The Properties of Life
(f) Reproduction
(e) Response to the environment
(g) Evolution
Life at Its Many Levels
– Biologists explore life at levels ranging from the
biosphere to the molecules that make up cells.
Biosphere
Ecosystems
Communities
Populations
Organisms
Organ Systems
and Organs
Tissues
Organelles
Nucleus
Molecules and Atoms
Atom
Cells
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Life in Its Diverse Forms
– Diversity is the hallmark of life.
• The diversity of known life includes 1.8 million species.
• Estimates of the total diversity range from 10 million to over
100 million species.
Grouping Species
– Biodiversity can be beautiful but overwhelming.
– Taxonomy is the branch of biology that names and
classifies species.
The Three Domains of Life
•
The three domains of life are
– Bacteria
B
i
– Archaea
– Eukarya
Chemistry of Life
– Matter is anything that occupies space and has mass.
– Matter is found on the Earth in three physical states:
• Solid
• Liquid
• Gas
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Chemistry of Life
– Matter is composed of chemical elements.
• Elements are substances that cannot be broken down
into other substances.
Change the number of PROTONS in the nucleus and you
change the ELEMENT
Atoms
– Each element consists of one kind of atom.
• An atom is the smallest unit of matter that still retains the
properties of an element.
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Protons
2
Neutrons
2
Electrons
Nucleus
Nucleus
Cloud of negative
charge (2 electrons)
Chemistry of Life
– Elements differ in the number of subatomic particles
in their atoms.
• The number of protons, the atomic number, determines which
element it is.
• An atom’s mass number is the sum of the number of protons
and neutrons.
j
• Mass is a measure of the amount of matter in an object.
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Periodic Table of the Elements
Legend
Solid
Liquid
Gas
Synthetic
Alkali metals
Alkali earth metals
Transition metals
Rare earth metals
Other metals
Noble gases
Halogens
Other nonmetals
Atomic number = number of protons within the nucleus
Chemistry of Life
– Twenty-five elements are essential to life.
– Four elements make up about 96% of the weight of
Carbon (C): 18.5%
the human body:
• Oxygen
Calcium (Ca): 1.5%
Phosphorus (P): 1.0%
Oxygen (O):
• Carbon
65.0%
Potassium (K): 0.4%
Sulfur (S): 0
0.3%
3%
• Hydrogen
Sodium (Na): 0.2%
Chlorine (Cl): 0.2%
• Nitrogen
Magnesium (Mg): 0.1%
Trace elements: less than 0.01%
Hydrogen (H):
9.5%
Boron (B)
Chromium (Cr)
Cobalt (Co)
Copper (Cu)
Fluorine (F)
Iodine (I)
Iron (Fe)
Nitrogen (N):
3.3%
Manganese (Mn)
Molybdenum (Mo)
Selenium (Se)
Silicon (Si)
Tin (Sn)
Vanadium (V)
Zinc (Zn)
Chemical Properties of Atoms
– Electrons determine how an atom behaves when it encounters
other atoms.
First electron shell
(can hold 2 electrons)
Electron
Outer electron shell
(can hold 8 electrons)
Hydrogen (H)
Carbon (C)
Atomic number = 1 Atomic number = 6
Nitrogen (N)
Atomic number = 7
Oxygen (O)
Atomic number = 8
© 2010 Pearson Education, Inc.
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