Uploaded February 2025 | Updated September 2026, 7 hours ago

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In this video, we look at variation and inheritance. First we explore how an individual's phenotype can be controlled by genetic and environmental factors. We then look at how sexual reproduction can lead to genetic variation within a species. Finally, we explore continuous and discontinuous variation.

Image credits:

Overweight cat
commons.wikimedia.org/wiki/File:Big_Fat_Red_Cat.jpg
Tripp, CC BY 2.0 creativecommons.org/licenses/by/2.0, via Wikimedia Commons

Obese mouse
commons.wikimedia.org/wiki/File:Fatmouse.jpg
The original uploader was Bigplankton at English Wikipedia.Later versions were uploaded by Sunholm at en.wikipedia., Public domain, via Wikimedia Commons

Chlorosis
commons.wikimedia.org/wiki/File:Banksia_integrifolia_02_ies.jpg
Frank Vincentz, CC BY-SA 3.0 creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons

Etiolated plants
commons.wikimedia.org/wiki/File:Nalaswan_barley_shoots.jpg
Kamal Ratna Tuladhar, CC BY-SA 3.0 creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Meiosis
commons.wikimedia.org/wiki/File:Meiosis_(261_35).jpg
Doc. RNDr. Josef Reischig, CSc., CC BY-SA 3.0 creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Fertilisation
commons.wikimedia.org/wiki/File:Sperm-egg.jpg
pdimages.com/web9.htm, Public domain, via Wikimedia Commons

Blood bag
commons.wikimedia.org/wiki/File:Blausen_0086_Blood_Bag.png
BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436., CC BY 3.0 creativecommons.org/licenses/by/3.0, via Wikimedia Commons

Ginger cat
commons.wikimedia.org/wiki/File:Ginger_house_cat.jpg
Carrolquadrio, CC BY-SA 4.0 creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons