The Origin of Species

Presentation about the different theories which tries to explain this

phenomenon

Introduction

• There are two big groups in which the origin of species are divided:

Non-evolution theories: Creationism and Fixism

Evolution ones theories: Lamarckism. Darwinism and Neo-Darwinism

Creationism

• Creationism is the religious belief that humanity, life, the Earth, and the universe are the creation of a supernatural being, most often referring to the Abrahamic God.

Fixism

• They are beliefs that affirm the different species of the planet have remained invariable throughout the time.

• All the alive beings were created as we see them at present. The Nature does not change, it was ended and unaltered from his formation.

Cuvier, to the thelft, and Linneo, to the right, supported this theory

Cuvier thought that changes were produced by huge catastrophes; this theory is called: “Catastrophism”

Lamarckism

• Living beings are distributes from simple (appeared by spontaneus generation) to more complex ones (by progresive transformations)

• Evolution is explained due to the function creates the organ.

• Transformations suffered by an organism are transmited by heredity to their offspring

A good example are the famous case of the girafe´s neck

Darwinism

• Current species are originated by ancient, common ones.

• It explains the evolution with the next steps: -Species suffer variations, which can cause advantages

or disavantages. -Natural selection will choose the “good” ones and

they will be transmited to their offspring.• Darwin know nothing about genetic

Neo Darwinism

• It´s the synthesis of: -Genetic discoveries of Mendel, that explains

how variations are produced. -Natural selection theory formuled by Darwin

Mendel rules Natural selection Neo Darwinism

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