Evidence for Evolution
Aligned to HS-LS4 — Next Generation Science Standards.
What this lesson teaches
Natural selection drives evolution: heritable traits that improve survival become more common. Fossils, anatomy, and DNA provide evidence.
Worked examples
Example 1
Antibiotic-resistant bacteria evolve because resistant individuals survive treatment and reproduce, passing resistance on.
Example 2
Whale skeletons carry a pelvis and leg bones with nothing attached to them — leftovers from ancestors that walked.
Example 3
Evolution has no goal. A trait spreads because it worked in one environment, and the same trait can be fatal when the environment changes.
Practice questions
- How does natural selection lead to change over time?
- Name two kinds of evidence for evolution.
- Why do antibiotics become less effective over time?
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Evidencia de la evolución
La selección natural impulsa la evolución: los rasgos heredables que mejoran la supervivencia se vuelven más comunes. Los fósiles, la anatomía y el ADN aportan evidencias.
Ejemplo 1: Las bacterias resistentes a antibióticos evolucionan porque los individuos resistentes sobreviven al tratamiento y se reproducen, transmitiendo esa resistencia.
Ejemplo 2: Los esqueletos de ballena conservan pelvis y huesos de pata sin nada unido a ellos — restos de ancestros que caminaban.
Ejemplo 3: La evolución no tiene meta. Un rasgo se extiende porque funcionó en un ambiente, y ese mismo rasgo puede ser mortal cuando el ambiente cambia.
More Life Science lessons
Teach this lesson today
An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.
Start free — no card required