Notes

Variation- any trait that makes an individual different than the rest of the species

Adaptation- any trait that makes an organism better suited to its environment

Selective pressure - Any factor that alters the behavior and fitness of living organisms within a given environment
Driving force of evolution and natural selection
Can be biotic (living) or abiotic (nonliving)

Niche - a position or role taken by a kind of organism within its community
May be occupied by different organisms in different places

1. Gradualism - slow, ongoing process in which one species changes into a new one



2. Punctuated equilibrium - long periods without change punctuated by periods of rapid change

Generally faster than gradumalim






Fossils- petrified remains of past life

Types of fossils
Mineralized fossils - minerals replace wood or bone to create a fossil made of rock
Carbonized - formed when pressure removes liquids and gases leaving only the carbon outline
Molds and cast-minerals fill an impression left by organisms
Trace fossils - preserved evidence of the activity of an organism
Original material - -ancient organisms in a substance
B. sedimentary rock - layer of sand silt and clay are compacted together
11. Determining fossil age
Relative age dating- the deeper dig the older the rocks and fossils get


10g of u-238 will become 5g after 4.5 billion year.
The other 5g will be lead-206
If a rock sample contains 25% potassium-40 and 75% argon-40 how old is the rock
How many half lives 2
How long is a half life. 2.6 billion years


lll. more clues about evolution
Embryology - similarities among embryos of different species show that there are evolution links
Homologous structures - body parts that are similar between different spies
Vestigial structures - structures that do not to seem to have a function


hominids - human like primates
Lived 4-6 million years
Ate meat and plante
Walk upright on two lags

Australopithecus - oldest hominid fossil ever
Discovered in 1974 in africa
Lived 3 million years ago
Nickname ‘’lucy’’
Homo habilis- lived 2 million years ago
It's name means “handy man” because it was discovered with stone tools
Homo erectus- lived 1.8 million years ago
Made simple hand axes
First to use fire
Homo neanderthalensis - lived 400,000 years ago
Shorts bodies thick bones
Living in caves with families
Homo sapiens lived 40,000 years ago today

Homo habilis made tools
Cro-magnon made cave drawings

a.Nucleus - central part of the atom
Contains (+) and neutrons (neutral)
B. Electron cloud - area around the nucleus
Contains electrons (-)
Isotopes - atoms of the same element with different numbers of neutrons
Electrons are arranged in energy levels within the cloud
If the outer is full the atom is stable. It will not react with any thing protons=Atomic number
Neutrons= atomic mass- atomic number
Electrons = protons

Element
Proton
Neutrons
Electrons
Oxygen
8
8
8
Calcium
20
20
20
Lithium
3
4
2















Groups - vertical columns on the periodic table
All elements of a group share certain properties



Periods- horizontal rows on the table
Predictable patterns of changes occur as you read from left to right across a period


Metals - left side of the ´stair line´
Nonmetals - right side if the ¨stair line¨
Metalloids - touchings the ¨stair line¨












Group 1 - alkali metals - include lithium sodium and others
> these need to lose one electron to be stable, so they are highly reactive
Group two - alkaline earth metals - include magnesium, calcium and others
> these need to lose two electron to be stable, so they are highly reactive also
Nonmetal element groups to know:
Group 17-halogens - include chlorine. Fluorine and others
> these need one more electron to be stable, so they are highly reactive
>group 1 elements will bond very easily with group 12 elements


these need to lose one electron to be stable, so they are highly reactive a











Valence electron- electrons in the outer energy level
-Determine how elements bond




Lewis structure / electron dot diagrams - represents valence electron as dots around chemical symbol




Covalent bond - occurs when electrons are shared



Ionic bonding practice
1.Walwncwe electrons




Physical change - only the appearance changes
*The basic materials are unchanged

Chemical changes- The basic materials have changed into new substances with different properties
Chemical reaction - process in which atoms of substances rearrange to form new substances
Reatances- substances the enter a reaction produces - substances that fit during the reaction
Sighns of a chemical reaction 1. Color change (not from a dye or stain)
2.oder change
3.bubbles
4.Precipitate - a solide that forms when 2 liquids are mixed
5 Temperature change
6.Light