Evolution -What’s up with that?

SPECIES A group of organisms that share similar characteristics and can reproduce among themselves to produce fertile offspring. In other words, a group of living things that are alike and that can have babies that can have babies.

EvolutionChange through time.

Theory of Evolution

New species are formed as they change over a period of time.

An early theory of evolution that was proposed in 1809 by Jean Baptise de Lemarck was the Theory of the Inheritance of Acquired Characteristics. Characteristics (traits) that are acquired (obtained) by an organism during their lifetime can be passed on to their offspring. We now know that this is not what happens.

Example: If a person gets big, bulky muscles, they should pass these on to their children.

CHARLES DARWINBorn 1809 in EnglandDied 1882 in England

Education:Edinburgh 2 terms to study medicineChrist’s College in Cambridge to study as a clergy

Known as the Father of Evolution

HMS BEAGLE1831 Darwin took a job as a naturalist on the survey ship the HMS Beagle . While in the Galàpagos Islands off the coast of South America, he noticed animals that were similar to but uniquely different from animals on the mainland. This made him wonder where new species come from and allowed him to formulate his theory of natural selection.

NATURAL SELECTION AND EVOLUTION

Natural selection occurs when organisms with traits best suited to their environment are more likely to survive and reproduce; and these traits are passed on to their offspring. In order to have natural selection, you must have variation in a species. Variation is when you have some inherited trait that makes an individual different from other members of the species. If that trait makes an organism better suited for its environment, it is called an adaptation. Camouflage coloring could be an example of an adaptation.

Conditions Required for Natural Selection

Overproduction of offspring

+ Inherited variation

+ Struggle to survive

= Differential reproductive success

DARWIN’S FINCHESBy studying the Galàpagos finches, Darwin theorized the animals must have originally come from the mainland. However, because they were isolated, the ones best suited to survive were the ones who reproduced and passed those helpful traits on to their offspring. After many generations, a separate species was formed.

ORIGIN OF THE SPECIESAfter more than 25 years, Darwin finally published his theory in 1859 in a book called On the Origin of Species by Means of Natural Selection. His theory become known as the theory of evolution through natural selection.

FOSSIL EVIDENCEToday, many evidences are used to support the theory of evolution, including fossils. Types of Fossils:mineralized fossils - petrified wood and fossilized bonesfrozen fossils - frozen wooly mammothsimprint fossils – leaves or bodies that leave an imprint in mud that becomes hard rockcast fossils – a fossilized footprintamber – insects get trapped in hardened resin

Phylogenetic Tree shows the theoretical evolutionary history of an organism.

MISCONCEPTIONS1. Evolution’s main focus is

not the origin of life. It deals primarily with how life changed after its origin.

2. Evolution does not state that humans evolved from apes, but rather that we shared a common ancestor.

3. Natural selection does not always lead to greater complexity.