Question

1. dna evidence

• the definition of being related to someone is sharing ____, or hereditary material.
• the video states that the strongest and ____ evidence for common ancestry is the dna that all life on earth shares.
• the more __ two organisms have in common, the more closely they are considered __.
• even complex organisms, like humans, share genes for basic cell functions with simple life forms, like ____.

1. the fossil record

• the __ is our greatest source of evidence for evolution because it shows that species from the past were very __ than they are today.
• the fossil record is considered ____ because we only have fossils for a fraction of species that have existed.
• to determine the age of fossils, scientists analyze structural evidence and use ____ evidence.
• new fossil evidence led scientists to conclude that the closest living relative of dinosaurs are ____, not reptiles.

exit ticket (dok 3)
in your own words, explain why dna evidence is considered the most compelling (strongest) evidence for common ancestry when compared to structural evidence (like comparing bones).

• (explain your reasoning here):

Explanation:

3. DNA Evidence (Filling the Blanks)

Step 1: First Blank (Definition of Related)

The definition of being related in terms of DNA is sharing DNA (genetic/hereditary) material. So the first blank: DNA (genetic/hereditary) material

Step 2: Second and Third Blanks (Strongest and Evidence Type)

The video states that DNA is the strongest and most common evidence for common ancestry (since all life shares DNA). So second blank: most common; third blank: common ancestry

Step 3: Fourth Blank (Relatedness of Organisms)

The more similarities (or traits/characteristics) two organisms have in common, the more closely they are considered related. So fourth blank: similarities (traits/characteristics)

Step 4: Fifth Blank (Simple Life Forms)

Even complex organisms share genes with simple life forms like bacteria (or prokaryotes, or single - celled organisms). So fifth blank: bacteria (prokaryotes, single - celled organisms)

4. The Fossil Record (Filling the Blanks)

Step 1: First Blank (Fossil Record as Evidence)

The fossil record is our greatest source of evidence for evolution because it shows that species from the past were very different than they are today. So first blank: different

Step 2: Second Blank (Incompleteness of Fossil Record)

The fossil record is considered incomplete because we only have fossils for a fraction of species that have existed. So second blank: incomplete

Step 3: Third Blank (Dating Fossils)

To determine the age of fossils, scientists analyze structural evidence and use radiometric (or relative/absolute) evidence. So third blank: radiometric (relative/absolute)

Step 4: Fourth Blank (Dinosaur Relatives)

New fossil evidence led scientists to conclude that the closest living relative of dinosaurs are birds, not reptiles. So fourth blank: birds

Exit Ticket (DOK 3)

DNA evidence is the strongest for common ancestry because DNA is the genetic blueprint passed down through generations. When we compare DNA sequences between organisms, the more similar their DNA is, the more recently they shared a common ancestor. Structural evidence (like bone comparisons) can show similarities in anatomy, but it can be misleading in some cases (e.g., convergent evolution where different species evolve similar structures independently). DNA, however, is a direct record of genetic inheritance, so shared DNA sequences (especially for highly conserved genes) provide a more precise and quantifiable measure of how closely related organisms are. For example, humans and chimpanzees share about 98% of their DNA, which is a strong indicator of a recent common ancestor, and this is more definitive than just looking at bone structures.

Answer:

DNA evidence is the strongest for common ancestry because it directly reflects genetic inheritance. DNA sequences are passed from parent to offspring, so similarities in DNA between organisms indicate a shared evolutionary history. Structural evidence (like bone comparisons) can be less precise, as convergent evolution can create similar structures in unrelated species. DNA provides a quantifiable, molecular - level measure of relatedness (e.g., high DNA similarity between humans and chimps shows close ancestry), making it more compelling than structural evidence.