Bio- Evolution

What are two ways scientists determine the age of fossils?

Relative dating (older layers are deeper) and absolute dating using radioactive decay (e.g., Carbon-14).

What are vestigial structures?

Structures with little or no function, left over from an ancestor (e.g., leg bones in snakes).

What are homologous structures?

Structures with a common origin but different functions (e.g., whale flipper and human arm).

What are analogous structures?

Structures with similar function but different origin (e.g., bird wing vs. insect wing).

What evidence does embryo development provide for evolution?

Similar embryonic stages in different species suggest common ancestry.

Who was Charles Darwin?

He developed the theory of natural selection and published 'On the Origin of Species' in 1859.

What is natural selection?

Organisms with traits best suited to the environment survive and reproduce more successfully.

What is artificial selection?

Humans select for desirable traits in organisms (e.g., crops, pets).

Who was Jean-Baptiste de Lamarck and what was his incorrect theory?

He believed organisms could change through use/disuse and pass acquired traits

What are the 5 key ideas of Darwin’s theory?

Variation, overproduction, struggle for survival, survival of the fittest, inheritance of traits.

What is speciation?

The formation of new species due to reproductive isolation.

What are four isolating mechanisms in speciation?

Morphological, behavioral, geographic, and temporal isolation.

What defines a species?

A group of organisms that can interbreed and produce fertile offspring.

What is a niche?

An organisms role and environment; no two species share the exact same niche.

What are the steps of speciation in Darwin’s finches?

1. Founders arrive

2. Isolation

3. Gene pool changes

4. Reproductive isolation,

5. Competition.

What causes genetic variation?

Mutations and meiosis.

What does the Hardy-Weinberg Principle state?

Allele frequencies remain constant if 5 conditions are met.

What are the 5 Hardy-Weinberg conditions?

Large population, no mutation, random mating, no migration, no natural selection.

What are the Hardy-Weinberg equations?

Allele frequency: p + q = 1; Genotype frequency: p² + 2pq + q² = 1

What did Kettlewell’s moth experiment show?

In polluted areas, dark moths survived better; in rural areas, light moths did. This supports natural selection.

Why did dark moths increase in polluted areas?

They were better camouflaged against soot-covered trees, so they were less likely to be eaten.