chapter 22 biology notes

What is gradualism (uniformitarianism)?

The idea that Earth's geological changes happen gradually over time through consistent processes.

What is catastrophism?

The belief that Earth's geological features formed suddenly due to catastrophic events.

Compare gradualism and catastrophism.

Gradualism: Slow, continuous processes (e.g., erosion). Catastrophism: Rapid, dramatic changes (e.g., volcanic eruptions).

What is evolution?

The process by which species accumulate differences from their ancestors as they adapt to different environments over time.

What is descent with modification?

The passing of traits from parent to offspring with changes over generations, explaining both unity and diversity in life.

What is natural selection?

A process where individuals with advantageous traits survive and reproduce at higher rates.

What is artificial selection?

Human-driven selection of individuals with desired traits for breeding purposes.

How do natural and artificial selection differ?

Natural selection: Driven by environmental pressures. Artificial selection: Driven by human preferences.

What are Darwin’s four observations about nature?

Variation exists in inherited traits. All species produce more offspring than the environment can support. Unequal survival leads to differential reproduction. Over generations, favorable traits accumulate in populations.

What are homologous structures?

Similar structures in different species inherited from a common ancestor.

What are vestigial structures?

Remnants of features that served a function in an organism's ancestors (e.g., human tailbone).

What is comparative embryology?

The study of embryonic development, showing similarities that suggest common ancestry.

What is convergent evolution?

Independent evolution of similar features in distantly related species due to similar environmental pressures.

What are analogous traits?

Similar traits in unrelated species, arising from convergent evolution rather than common ancestry.

What is biogeography?

The study of the geographic distribution of species, supporting evolution (e.g., species on islands).

What is the importance of Pangaea in evolution?

The supercontinent that explains the distribution of species before it split into separate continents.

What are strata?

Layers of sedimentary rock where fossils are found; deeper strata contain older fossils.

What are adaptations?

Inherited traits that increase an organism’s chances of survival and reproduction.

Why is genetic variation important?

It ensures populations can adapt to changing environments over time.

Why do individuals not evolve?

Evolution occurs in populations over generations, not in individual organisms.

What is MRSA?

Methicillin-resistant Staphylococcus aureus, an example of natural selection where bacteria evolved resistance to antibiotics.

What are the four types of data used to document evolutionary change?

Direct observations (e.g., MRSA). Fossil record (e.g., transitions between species). Homology (e.g., shared anatomical structures). Biogeography (e.g., species distribution).

What is the fossil record?

Historical remnants of organisms that document the progression of life through Earth's history.

What is paleontology?

The study of fossils.

What did Darwin mean by "survival of the fittest"?

Organisms with traits best suited to their environment are more likely to survive and reproduce.

What is adaptive evolution?

Evolutionary changes that result in a better fit between organisms and their environment.

What are three key observations of life?

Organisms are adapted to their environments. There are shared characteristics (unity of life). There is diversity of life.

What is the unity of life?

All organisms share DNA and common ancestry.

What is the diversity of life?

Differences among species due to adaptation to various environments.

What role do fossils play in understanding evolution?

Fossils provide evidence of how species have changed over time.

What is the origin of species?

Darwin's book explaining natural selection as the mechanism for evolution.

Why did Darwin delay publishing his ideas?

His ideas challenged prevailing theological beliefs.

Compare gradualism (uniformitarianism) and catastrophism.

Gradualism: Earth's changes occur slowly over time through consistent processes. Catastrophism: Earth's features formed suddenly due to catastrophic events.

How does descent with modification explain adaptations and the unity and diversity of life?

Descent with modification explains how traits are passed from parent to offspring with changes over generations, leading to adaptations in organisms and explaining the unity (common ancestry) and diversity of life (adaptation to different environments).

How do natural and artificial selection differ?

Natural selection is driven by environmental pressures, while artificial selection is driven by human preferences in choosing desirable traits for breeding.

What are Darwin’s four observations about nature?

1. Variation exists in inherited traits. 2. Species produce more offspring than the environment can support. 3. There is unequal survival leading to differential reproduction. 4. Favorable traits accumulate in populations over generations.

Summarize the main ideas of natural selection.

Natural selection is the process where individuals with advantageous traits have higher survival and reproductive rates, leading to the accumulation of these traits in a population over time.

What role do individuals versus populations play in evolution?

Individuals do not evolve; evolution occurs in populations over generations through changes in the frequency of traits.

List two direct observations of evolutionary change and explain.

1. MRSA (Methicillin-resistant Staphylococcus aureus): Bacteria evolved resistance to antibiotics. 2. Fossil records: Show transitions between species over time.

What are homologous structures?

Similar structures in different species that have been inherited from a common ancestor.

What are the four types of data used to document evolutionary change?

1. Direct observations (e.g., MRSA). 2. Fossil record (e.g., transitions between species). 3. Homology (e.g., shared anatomical structures). 4. Biogeography (e.g., species distribution).