Early Study of Evolution
Who is the scientist famous for proposing the theory of evolution by natural selection and who wrote "On the Origin of Species"?
Charles Darwin
What is "natural selection" in one short sentence?
Natural selection is the process where organisms better suited to their environment tend to survive and have more offspring.
What does "evolution" mean for a population over time?
Evolution is change in the traits of a population over many generations.
What is a fossil?
A fossil is preserved remains or traces of ancient organisms (e.g., bones, shells, imprints).
What are homologous structures? Give one easy example.
Homologous structures are body parts with similar structure from a common ancestor (e.g., the limb bones of humans, bats, whales).
On which island group did Darwin make many of his important observations about species and variation?
Galapagos Islands
In natural selection, which individuals are more likely to survive and reproduce? (Give the key trait of those individuals.)
Individuals with advantageous traits (better adapted) are more likely to survive and reproduce.
True or False: Evolution changes individual organisms during their lifetime. (Answer and briefly explain.)
False — evolution is change in populations over generations, not change within an individual's life.
How can fossils show that life on Earth has changed over time?
Fossils from older layers are different from newer layers, showing changes in organisms over time.
What are analogous structures? Give one simple example.
Analogous structures are body parts that serve similar functions but evolved independently (e.g., wings of insects vs. wings of birds).
What is the name of the ship Darwin traveled on during his voyage where he collected observations?
HMS Beagle
What role does the environment play in natural selection?
The environment "selects" which traits are beneficial; traits that help survival/reproduction become more common.
Define "adaptation" and give one simple example animals might have.
An adaptation is a trait that increases an organism's chance to survive and reproduce (e.g., camouflaged fur).
What is a transitional fossil and why is it important? Give a simple example
A transitional fossil shows features intermediate between groups (e.g., Archaeopteryx showing bird and reptile traits).
How can similarities in DNA and proteins between species be used as evidence for common ancestry? (short explanation)
DNA and protein similarities show that species with more similar sequences share a more recent common ancestor; the closer the match, the closer the relationship.
Darwin noticed that finches on different islands had different beak shapes. What idea about species did this observation support?
That species can change over time and adapt to different environments; common ancestry with modification
Name and briefly define the three main requirements for natural selection to occur (variation, inheritance, and differential survival/reproduction).
Variation (individual differences), inheritance (traits passed to offspring), differential survival/reproduction (some leave more offspring).
Describe how mutation and genetic variation contribute to evolution.
Mutations create new genetic variation; this variation can be acted on by natural selection, leading to evolutionary change.
What does the order of fossils in sedimentary rock layers generally tell scientists about age (older vs. younger)?
Older fossils are usually found in deeper layers; younger fossils are nearer the surface.
What is embryology and how can comparing embryos of different animals provide evidence for evolution?
Embryology studies early development; similar stages in embryos of different animals suggest common ancestry (e.g., vertebrate embryos share features like pharyngeal pouches).
Explain how Darwin used variation and competition in nature to build his idea of natural selection
Darwin explained that individuals in a species vary; those with traits better suited to their environment are more likely to survive and reproduce, passing those traits on so the population changes over time
A population of moths lives in a forest where tree bark becomes darker due to pollution. Describe how natural selection could change the moth population over several generations.
Darker tree bark makes lighter moths more visible to predators; darker moths survive and reproduce more, so over generations the population becomes darker.
Explain, in simple terms, how isolation of populations (like being separated on different islands) can lead to the formation of new species.
When populations are isolated, they accumulate different mutations and adapt to different environments; over time these differences can become great enough that they become separate species.
Describe how comparing fossils from different layers can support the idea that species have changed gradually over long periods.
Fossils show gradual changes in form across layers, consistent with species changing over long time spans.
Give two different kinds of evidence (not fossils) that support the theory of evolution, and briefly explain how each supports it.
Examples: (a) Comparative anatomy — similar bone structures suggest common ancestry; (b) Molecular evidence — DNA/protein similarities show relationships and common descent.