Subscribe

9th grade · Science · Unit 5 of 14

Evolution & Selection

Variation, adaptation and how populations change over time.

What your child practices

Practices variation, adaptation, natural and artificial selection, mutations, the evidence for evolution from fossils and rock layers, and how new species can form.

Texas Essential Knowledge and Skills (TEKS) teks student expectation: B.10(A); B.10(B) · natural selection acting on populations through inherited variation and competition

How we explain it

Children can open this short lesson before they practice.

  1. Variation and mutations give individuals different traits. Adaptations help them survive where they live.
  2. Natural selection lets well-suited individuals reproduce more; in artificial selection, people choose.
  3. Fossils and rock layers show life changed over time, starting with single-celled organisms.

Example: A cactus stores water in its thick stem. This is an adaptation to what? Storing water helps when rain is rare. Answer: dry climates

Evolution & Selection in Texas

In the Texas Essential Knowledge and Skills (TEKS), this is unit 5 of 14 in 9th grade Science, after Infectious Disease and before Photosynthesis & Respiration.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Texas Education Agency (TEA)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    A difference between natural and artificial selection is that…

    • in natural selection, humans choose
    • in natural selection, the environment does the selecting
    • only artificial selection involves traits

  2. Question 2

    If a climate becomes colder, the selective pressures on a population of animals will…

    • change
    • stay exactly the same
    • disappear

  3. Question 3

    Which of these must be true for natural selection to occur?

    • every organism is the same
    • traits cannot be passed on
    • traits vary and can be inherited

  4. Question 4

    Variation within a species means…

    • individuals have different traits
    • no individuals reproduce
    • all individuals are identical

  5. Question 5

    Fossils give evidence of evolution because they…

    • show what organisms looked like long ago
    • are alive today
    • are made in laboratories only

  6. Question 6

    Sexual selection is when…

    • traits that help attract mates become more common
    • traits that help with digestion are lost
    • animals avoid all mates

More 9th grade