evol first 6 lecs

What is biological evolution?

Changes in inherited traits of populations over generations.

What is the difference between microevolution and macroevolution?

Small changes within populations versus large evolutionary changes over time.

What did Aristotle propose?

Life forms belong in a fixed hierarchy called the Great Chain of Being.

What did Linnaeus contribute?

Created a system for naming and classifying organisms.

What did Lamarck propose?

Traits gained during life could be passed to offspring.

What is uniformitarianism?

The natural processes we see today also operated in the past.

What did Darwin mean by descent with modification?

Species change over generations and share common ancestors.

What are Darwin's four postulates?

Variation, inheritance, excess offspring, and unequal reproductive success.

What is natural selection?

Individuals with advantageous inherited traits tend to leave more offspring.

What did Mendel discover?

How traits are inherited from parents to offspring.

What is the Modern Synthesis?

Combining genetics with Darwin's theory of evolution.

What does a phylogenetic tree show?

Evolutionary relationships between organisms.

What do nodes and branches represent?

Nodes show common ancestors; branches show evolving lineages.

What is a clade?

A common ancestor and all its descendants.

How do you identify the closest relatives on a tree?

Find which species share the most recent common ancestor.

Does rotating branches around a node change relationships?

No. The branching pattern stays the same.

Can one living species be assumed to be another living species' ancestor?

No. They may instead share a common ancestor.

What are homologous characters?

Traits inherited from a common ancestor.

What are analogous characters?

Similar traits that evolved independently.

What is the difference between ancestral and derived traits?

Ancestral means older; derived means changed from the ancestral form.

What is a synapomorphy?

A derived trait shared by multiple groups through common ancestry.

What is an outgroup used for?

To identify which trait states are ancestral and which are derived.

What is parsimony?

Choosing the evolutionary tree requiring the fewest changes.

What is homoplasy?

Similar traits caused by independent evolution or evolutionary reversals.

What is an evolutionary reversal?

When a trait changes back to its ancestral form.

What is a molecular clock?

Using DNA differences to estimate when species separated.

What is the difference between monophyletic and paraphyletic groups?

One includes all descendants of an ancestor; the other leaves some out.