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In this video, we look at genetic and environmental causes of variation. First we explore what is meant by interspecific and intraspecific variation. We then look at how variation can have genetic causes such as alleles, independent assortment of chromosomes and crossing-over during meiosis and random fertilisation of gametes. Finally, we look at how variation can be caused by the environment.
Image credits
Astronotus ocellatus
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Jón Helgi Jónsson (Amything), CC BY-SA 3.0 creativecommons.org/licenses/b..., via Wikimedia Commons
Fungus
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Simon Burchell, CC BY-SA 4.0 creativecommons.org/licenses/..., via Wikimedia Commons
Hyena
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Charles J. Sharp, CC BY-SA 4.0 creativecommons.org/licenses/..., via Wikimedia Commons
Peacock
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Magnus Johansson, CC BY-SA 2.0 creativecommons.org/licenses/..., via Wikimedia Commons
Mamba
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Holger Krisp, CC BY 3.0 creativecommons.org/licenses/..., via Wikimedia Commons
Snail
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Lauren, CC BY 3.0 creativecommons.org/licenses/..., via Wikimedia Commons
Black cat
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Sage Ross, CC BY-SA 3.0 creativecommons.org/licenses/b..., via Wikimedia Commons
Orange tabby
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Orange_tabby_cat_sitting_on_fallen_leaves-Hisashi-01.jpg: Hisashi from Japanderivative work: Caspian blue, CC BY-SA 2.0 creativecommons.org/licenses/..., via Wikimedia Commons
Black and white cat
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Hisashi from Japan, CC BY-SA 2.0 creativecommons.org/licenses/..., via Wikimedia Commons
Orange, black and white cat
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Fquestier, CC BY-SA 3.0 creativecommons.org/licenses/..., via Wikimedia Commons
Ob mouse
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The original uploader was Bigplankton at English Wikipedia.Later versions were uploaded by Sunholm at en.wikipedia., Public domain, via Wikimedia Commons
Melanoma
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See page for author, Public domain, via Wikimedia Commons
Havanese litter
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Cartman0052007 at English Wikipedia, CC BY 3.0 creativecommons.org/licenses/..., via Wikimedia Commons
Meiosis
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Doc. RNDr. Josef Reischig, CSc., CC BY-SA 3.0 creativecommons.org/licenses/..., via Wikimedia Commons
Fertilisation
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www.pdimages.com/web9.htm, Public domain, via Wikimedia Commons
Scar
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Starvee44 at English Wikipedia, Public domain, via Wikimedia Commons
Blue hydrangea
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I, MJJR, CC BY 2.5 creativecommons.org/licenses/..., via Wikimedia Commons
Pink hydrangea
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Basketball
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Christopher Johnson, CC BY-SA 2.0 creativecommons.org/licenses/..., via Wikimedia Commons
Blood
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Alden Chadwick from Leeds, UK, CC BY 2.0 creativecommons.org/licenses/..., via Wikimedia Commons