evolution quiz 1

darwins theory

Natural Selection: Organisms with traits better suited to their environment survive and reproduce more. Over time, those traits become more common in the population.

Explain evolution of a trait using 4 steps of natural selection:

variation, competition, survival advantage, reproduction

weaknesses in darwin’s theory

didnt know about genes and dna, couldnt explain varation, and slow to explain sudden changes

where did darwin make these observations

galapagos islands

lamarcks theory

Use and Disuse – If you use a body part a lot, it gets stronger. If you don’t, it shrinks or disappears.

Inheritance of Acquired Traits – Traits you get during your life can be passed on to your kids.

Explain evolution of a trait using Lamarck’s theory (giraffes)

• Giraffes stretch their necks to reach high leaves.

• Their necks get longer from stretching.

• They pass on those longer necks to their babies.

• Over generations, giraffes have super long necks

modern theory of evolution

based on the recognition that it is POPULATIONS that evolve, not individuals.

population

A group of the same species living in the same area that can interbreed.

gene pool

All the genes and variations (alleles) in that population.

biogeography

The study of where species live now and where their ancestors lived.

How & where do most fossils form?

Fossils usually form in sedimentary rock (like mud or sand) where dead organisms are buried quickly

relative dating

Fossils are dated based on layer order

absolute dating

Uses radioactive decay (like carbon-14 or uranium) to find the actual age in years.

limits of fossil record

• Fossils don’t form for all organisms (soft stuff decays).

• Most are missing, destroyed, or undiscovered.

• Doesn’t show every step — we’re often piecing together a puzzle with gaps.

homologous structures

same structure different function

analogous structures

same structure different function

vestigial structures

Leftover body parts that once had a function but don’t anymore. ex appendix

How can a DNA sequence of a gene be used to determine the relatedness of two species?

Compare gene sequences — the more similar, the more closely related.

What are pseudogenes?

Genes that used to work but are now "turned off" by mutations.

How can amino acid sequences be used to determine the relatedness of two species?

If two species have similar amino acid sequences, their DNA is also similar.

How can embryology be used to determine the relatedness between two species?

Early embryos of different species often look super similar, showing they came from a common ancestor.

carolus linnaeus

• Father of taxonomy.

• Created the binomial nomenclature system (Genus species).

• Organized species into groups, laying groundwork for understanding relationships, but did not support evolution.

georges cuvier

• Developed the theory of catastrophism.

• Studied fossils and established extinction as a fact.

• Believed species did not change over time; they were wiped out and replaced.

thomas malthus

• Wrote about population growth and limited resources.

• Proposed that more individuals are born than can survive, leading to competition.

• Inspired Darwin’s concept of natural selection.

charles lyell

• Developed the theory of uniformitarianism.

• Proposed that Earth changes slowly over long periods through natural processes.

• Supported the idea that Earth was old enough for evolution to occur.

jean baptiste de lamarck

• Proposed that organisms change over time through use and disuse of traits.

• Believed acquired traits could be passed on to offspring (incorrect).

• First to propose a full theory of evolution.

charles darwin

• Developed the theory of natural selection.

• Argued that species evolve over time due to variation, competition, and survival of the fittest.

• Published "On the Origin of Species."

alfred wallace

• Independently developed a theory of natural selection similar to Darwin’s.

• His work encouraged Darwin to publish his own theory.

• Studied species in Southeast Asia.

gregor mendel

• Father of genetics.

• Discovered how traits are inherited using pea plants.

• Explained inheritance through dominant and recessive alleles, supporting modern evolution theory.

hugo de vries

• Proposed the mutation theory of evolution.

• Suggested that mutations create variation and drive evolution.

• Helped connect Darwin’s ideas with genetics.

erasmus darwin

• Charles Darwin’s grandfather.

• Believed in the idea of common descent.

• Wrote about evolution before Charles but lacked scientific evidence.

georges louis-leclerc

• Proposed that species could change over time.

• Suggested the Earth was much older than previously believed.

• Believed in common ancestry but didn’t fully embrace evolution.

august weismann

• Disproved Lamarck’s idea of inherited acquired traits.

• Showed that only changes in reproductive (germ) cells are inherited, not body (somatic) cells.

• Strengthened the role of genetics in evolution.

james hutton

• Founder of modern geology.

• Proposed gradualism: Earth’s geological features formed slowly over time.

• Suggested Earth was ancient, supporting time needed for evolution.