BIOL 1307 Darwin and The Origin of Species

What is the best description of the theory of evolution?

An explanation regarding what happened after life appeared and how it has changed and diversified over billions of years once it appeared.

Hypotheses

Tentative and testable explanations about the natural world

Theory

A well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses

What are the 3 striking observations regarding life?

Organisms are incredibly well suited to their environments, there are many shared characteristics among life forms, and there is extraordinary diversity even among shared characteristics

Biological evolution refers to the cumulative changes that occur in a ______________ over time

population

Microevolution

Changes in gene frequency in a population from one generation to the next

Macroevolution

The descent of different species from s common ancestor over many generations

Endemic

Animals that live in a certain region are found nowhere else on earth

Gene flow

Exchange of genetic information between regions

The beaks of the finches were __________ to the specific foods available on their island

adapted

Natural selection

A process by which individuals who have inherited certain traits survive and reproduce because of those traits

What are the 2 observations Darwin made when studying evolution?

Members in a population often vary in inherited traits and species can produce more offspring than their environment can support, and many of these fail to survive and reproduce

what 2 inferences did Darwin make?

Individuals whose inherited traits give them a higher probability of surviving and reproducing (higher fitness) in a given environment tend to leave more offspring than do other individuals and the unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

____________ _____________ is the mechanism that selects for advantageous traits and increases their frequency within a population

Natural selection

____________ ___________ is a change in species over time due to that natural selection of favorable traits

Biological evolution

What did Darwin believe about unity among species?

That it indicated different species share common ancestors

Beak shape is controlled by __________ _______

heritable genes

What are the requirements for evolution by natural selection?

1. Individuals vary in some traits

2. Some of the differences in traits are passed along to offspring: this requires a genetic basis to the trait i.e. heritability

3. Different individuals produce different numbers of surviving offspring: produce different numbers or different numbers survive'

4. The particular value of a trait is connected to the number of offspring produced: traits that allow for more offspring to be produced are said to be “naturally selected”

Individuals ___ _____ evolve in their lifetime because they cannot change their inherited genes

do not

Natural selection can only act upon…

traits that vary within a population

What is considered a “favorable trait” depends on…

the existing environment

Definition of evolution

A change in the frequency of an allele within a population from one generation to the next

Natural selection can occur ________ heritability, but evolution by natural selection _________!

without; cannot