Sexual Reproduction Activity Build a Karyotype with Chromosomes from Gametes

Description

Kids LOVE this activity! This karyotyping activity clearly shows that gametes have half the number of chromosomes as the parent, and they combine to make a complete zygote. Students are excited to find out if their baby koala is a male (called a buck) or a female (called a doe)! This is a fun – and minimally awkward – way to teach sexual reproduction!

This activity reinforces:

• Sexual reproduction requires two parents.
• Gametes have half the number of chromosomes as the parents.
• Gametes combine to make a zygote in the process of fertilization.
• Chromosomes have homologous pairing and differ based on size and banding pattern.
• A karyotype is an organized map of chromosomes.
• Different organisms have different numbers of chromosomes.
• XX makes a female koala offspring and XY makes a male koala offspring.

In this activity, students will:

• Read background information about sexual reproduction, including the terms gametes, zygote, fertilization, sperm, egg, and homologous chromosomes.
• Obtain a koala egg and a koala sperm. (We do this activity in pairs, so one student gets the male gamete and the other gets a female gamete.)
• Cut out the chromosomes and match the homologous pairs using a provided key. (Koalas have 16 total chromosomes, so the cutting is minimized compared to a human karyotype.)
• Paste the homologous chromosome pairs onto their karyotype page and identify whether it is male or female.
• Answer follow-up questions on a worksheet.

Includes:

• Introductory reading passage with koala chromosome key
• Koala egg and koala sperm (2 versions to make male and female babies)
• Blank koala karyotype
• Follow-up questions worksheet
• Helpful teacher notes

NGSS Standards:

• MS-LS3-2
• Science & Engineering Practice: Developing and using models

Teacher Notes:

• You may also find our Asexual & Sexual Reproduction Test helpful.
• Please note: This resource is NOT editable.
• Answer key included.
• Check out more resources in the asexual and sexual reproduction section of our shop!