The
Fossil Record
Fossil Record
What is a fossil? How old must an organism be to become a fossil?
Remains or traces of ancient organisms preserved in rock.
10thousand years old
What is a homologous structure?
Structures with similar anatomy due to common ancestry, even if function differs.
What does "analogous structure" mean?
Structures that serve similar functions but evolved independently.
What is embryology?
The study of development of embryos from fertilization to later stages.
what is evolution
Change in organims over time
Using the Law of Stratification : How can fossils show the existence and extinction of organisms on earth. Give one short example.
Fossils appear in different rock layers showing older forms in deeper layers and newer forms above;
Give one simple example of homologous structures in different organisms.
Example: forelimbs of mammals (human arm and bat wing) or bone patterns in vertebrate limbs.
Give one simple example of homologous structures in different organisms.
Example: wings of insects vs. wings of birds.
What is one reason scientists compare embryos of different species?
To find developmental similarities that indicate common ancestry.
Which Scientist is known as the Father of Evolution
Charles Darwin
What does the term "transitional fossil" mean? Name one example (common example is fine).
Ex Tiktaalik
A fossil that shows intermediate traits between groups (example: Archaeopteryx between dinosaurs and birds; Tiktaalik between fish and tetrapods).
Why do homologous structures support the idea of common ancestry? (one-sentence answer)
They show shared inherited structures from a common ancestor.
Why do homologous structures support the idea of common ancestry? (one-sentence answer)
hey show shared inherited structures from a common ancestor.
How can comparing DNA sequences between species provide evidence for evolution? (short answer)
200: Similar DNA sequences indicate shared ancestry; greater similarity usually means a closer relationship.
What is divergent evolution ?
Divergent evolution is when related species evolve different traits from a common ancestor to fit new environments (like Darwin's finches with varied beaks), leading to homologous structures
Explain how radiometric dating is used to estimate the age of fossils (one or two sentences, mention decay of isotopes).
Radiometric dating measures decay of radioactive isotopes .(e.g., carbon-14 for recent, uranium-lead for older) to estimate absolute ages.
Describe how the forelimbs of mammals (for example, human arm, whale flipper, bat wing) are considered homologous — what is shared?
Name 2 specific structures of the arm.
Shared bone arrangement (humerus, radius, ulna, carpals, metacarpals, phalanges) across these limbs indicates common origin.
What is a vestigial structure then, give one example of a vestigial structure in humans.
Reduced or nonfunctional organs/traits leftover from ancestors.
Example: human appendix or tailbone (coccyx), wisdom teeth.
What does it mean when two species have a LOW percent similarity in their DNA sequences? (one-sentence)
It means they share a LESS recent common ancestor and more differences have accumulated between the two species.
More distantly related
What is Convergent Evolution ?
convergent evolution is when unrelated species develop similar traits (like sharks, dolphins, and ichthyosaurs) because of similar environmental pressures, resulting in analogous structures.
if you have a isotope with 100g of Carbon-14 with a half life of 20 years . How much will be left of
Carbon -14 in 80 years ?
6.25 grams left
4 half lives
20-20-20-20 = 80 years
50g-25g-12g-6.25g
Explain how homologous structures together strengthen evidence for common ancestry by divergent evolution.
Homologous structures arise from divergent evolution indicate recent common ancestry. Different environments influenced changes in triatis for various organisms.
How do analogous structures differ from homologous structures in what they tell us about evolution?
Analogous structures are similar structures with same functions but different internal anatomy. organimss arise from convergent evolution and do not indicate recent common ancestry.
Homologous structures are similar in internal anatomy but have different functions and indicate recent common ancestry.
Name one organ or structure that begins forming very early in animal embryos (simple answer).
Example: neural tube, heart, limb buds, or somites.
Head, tail, gills pharyngeal pouches, eyes
Describe three types of evidence for Evolution and explain how each supports the theory of evolution.
Fossil Record, Comparative Anatomy , EMbryology, DNA Molecular Evidence