Charles Darwin

• A naturalist considered the father of evolution due to his contributions in that subject area.

Homologous Structures

Structures that share a common ancestry for example a bat wing, a whale fin, a cat arm and a human arm.

Vestigial Structures

Vestigial structures are anatomical structures which have lost all of their original function through evolution.

TAIL FOUND IN 6 YEAR OLD GIRL.

WHAT DO THEY MEAN WHEN THEY

SAY - HUMANS

AND APES – NOT THAT

FAR APART!

Example of a VESTIGIAL Structures

What conclusion can you draw about humans, cats, whales, and bats?

Humans, cats, whales, and bats have a common

ancestor.

These are examples of homologous structures.

Natural Selection

NATURAL SELECTION LAB

Natural selection has no intentions or senses; it cannot sense what a species “needs.” If a population happens to have the genetic variation that allows some individuals to survive a particular challenge better than others, then those individuals will have more offspring in the next generation, and the population will evolve. If that genetic variation is not in the population, the population may still survive (but not evolve much) or it may die out. But it will not be granted what it “needs” by natural selection.

NATURAL SELECTION

NATURAL SELECTION

MOTH POPULATION IN POLLUTED FOREST

0

100

200

300

400

500

600

700

800

Yr. 1 Yr. 3 Yr. 5 Yr. 7 Yr. 9

YEAR

NU

MB

ER

OF

MO

TH

S

RE

CA

PT

UR

ED

DARK MOTHS

LIGHT MOTHS

CAPTURE OF

1. According to the graph, in year 1 how many more dark moths were captured than light moths?

2. Draw a graph that would communicate results of the elimination of the pollution?

NATURAL SELECTION

Half-Life

Describes how long it takes for half of the radioactive atoms in a sample to decay. For example a half-life of Carbon 14 is the equivalent of 5730 years.

HALF - LIFEWORK IN TEAMS OF 2 AND FIND THE PAGE IN YOUR BOOK THAT TELLS YOU ABOUT “HALF-LIFE”. YOU HAVE 10 MINUTES TO ANSWER THESE QUESTIONS BY FINDING THE INFORMATION ON THAT PAGE.

1.WHAT IS THE HALF-LIFE OF CARBON-14?

2.HOW LONG WOULD IT TAKE A 12g (gram) SAMPLE OF CARBON-14 TO DECAY TO 3 GRAMS?

3.WHAT DOES THE TERM HALF-LIFE DESCRIBE?

AFTER WE DISCUSS OUR FINDINGS:

CREATE A GRAPH THAT WOULD REPRESENT 12G OF CARBON-14 DECAYING DOWN TO 3 GRAMS – DON’T FORGET THAT THE DECAYED CARBON-14 DOES NOT DISAPEAR – IT BECOMES THE “DAUGHTER MATERIAL”. THE DAUGHTER MATERIAL FOR CARBON-14 IS NITROGEN.

1. WHAT IS THE HALF-LIFE OF CARBON-14? 5,730 YEARS

HALF – LIFE: ANSWERS

2. HOW LONG WOULD IT TAKE A 12g (gram) SAMPLE OF CARBON-14 TO DECAY TO 3 GRAMS?

11460 YEARS

3. WHAT DOES THE TERM HALF-LIFE DESCRIBE? HOW LONG IT TAKES FOR ONE-HALF OF

THE RADIOACTIVE ATOMS IN A SAMPLE TO DECAY AND TURN INTO ANOTHER TYPE OF ATOM.

Radioactive Dating

• Using the amount of a radioactive element left on a fossil or rock to determine its age.

Adaptation

• Any change in a trait that increases the likelihood that an organism will survive or reproduce.

Balancing Selection

• This term is used by scientists to refer to the situation in which two opposing selective forces affect the frequency of an allele in a population.

Directional Selection

• This is how biologists call unopposed selection where the frequency of alleles in one direction.

Ecological Races

• Are populations of the same species that differ genetically because they have adapted to different living conditions

Divergence

• Often ecological races become increasingly different due to accumulation of differences. It happens because natural selection favors different survival strategies.

Gradualism

• It’s a hypothesis that states that evolution occurs at a slow constant rate.

Punctuated Equilibria

• Is the hypothesis that evolution occurs at such irregular rates for example short periods of rapid species formation followed by long periods during which little evolution occurs.