Theories of Evolution

Flashcards about the theories of evolution. Includes the definition of terms, the process of evolution, and information about Darwin and Lamarck.

What is the definition of a scientific theory?

An idea about how something in nature works that has gone through rigorous testing through observations and experiments.

What is speciation?

Occurs when a group within a species separates from other members of its species and develops its own unique characteristics.

What is a species?

A group of organisms that can breed with one another and produce fertile offspring.

What is evolution?

The process by which different kinds of species change over time; descent with modification.

What does 'descent' imply in the context of evolution?

Inheritance.

What does 'modification' refer to in the context of evolution?

Changes in traits from generation to generation.

What is a gene pool?

The entire collection of genes and their alleles in a population.

How is allele frequency calculated?

The number of copies of that allele, divided by the total number of alleles in a population.

What is the theory of evolution?

A theory that all living species have developed as a result of changes in their genetic material over time.

What is microevolution?

Small, generation-by-generation changes occurring in every population or species.

What is macroevolution?

The appearance of new species over long periods.

Who was Jean Baptiste de Lamarck?

The first evolutionist to believe that organisms change over time.

What are Lamarck’s Three Theories?

The Theory of Need, The Theory of Use and Disuse, and The Theory of Acquired Characteristics.

What is the Theory of Need?

Organisms change in response to their environment.

What is the Theory of Use and Disuse?

Organs not in use will disappear, while organs in use will develop.

What is the Theory of Acquired Characteristics?

Acquired characteristics are inherited by their offspring and propagated by the next generation.

How was Lamarck's Theory of Evolution disproven?

August Weismann amputated the tails of mice and bred them, producing new generations of mice who had perfectly healthy tails; The discovery of DNA which was static and did not change over a person's lifetime.

Who is Charles Darwin?

Popular for his theory of evolution based on Natural Selection.

What book did Charles Darwin publish in 1859?

On the Origin of Species that signifies the survival of the fittest.

Who is Alfred Russel Wallace?

Proposed that evolution occurs due to the phenomenon called natural selection.

What is the Darwinian Theory?

Just like people are not of the same height, not all giraffes were born with the same neck length. Some were born with longer necks. As food became scarce, those with longer necks could reach food and survive, those with shorter necks starved and died. Since only long neck giraffes are reproducing, eventually overtime, all giraffes came to have long necks. Given enough change and time, new species could evolve.

What is the Theory of Natural Selection?

The survivors will pass on their better genes to their offspring who will also show this beneficial variation; It is the process whereby organisms better adapted to their environment tend to survive and produce offspring - the survival of the fittest.

What are the five key points of Natural Selection?

Overproduction, Variation, Competition, Adaptation, Speciation

What challenges did Darwin encounter?

Darwin’s theory of evolution by natural selection wasn’t very popular that time as it went against the God’s creation model that the church is teaching and the society believed in; Darwin failed to explain the source of variations in organisms since genes and chromosomes were not yet discovered that time.