8.2 Explore Male and Female

Sex and gender are not binary

In the first few sections of this chapter, we’ll be exploring differences between “males” and “females” in non-human organisms and how biologists define those categories. However, sex and gender are not strictly binary — there is an astounding and beautiful array of sex-related traits across species that don’t fit into male vs. female categories. Additionally, as described in the Introduction to Chapter 1, sex and gender are not the same thing, and we use the term gender only for humans. We’ll explore topics like intersex characteristics and gender non-conformity in humans later in this chapter. We also recognize that the authors of this textbook are cisgender and cannot fully explain the experiences of trans, non-binary, genderfluid, two-spirit, and other non-cisgender people. We welcome feedback about our discussion of sex and gender.

 

Each image below contains one male and one female. For each one, determine which individual is the male and which is the female. As you are deciding, take note of the criteria you are using to make your decision.

 

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Figure 8.4 Golden Orb-weaver spiders (Nephila pilipes) [1]

[1]

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Figure 8.5 Pygmy seahorses (Hippocampus japapigu) (A) a pregnant seahorse (B) this seahorse is the sex that does not experience pregnancy [2]

[2]

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Figure 8.6 Pair of mating marsh fritillaries (Euphydryas aurinia) [3]

[3]

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Figure 8.7 Two grass snakes (Natrix natrix) coiling around each other. [4]

[4]

Each pair includes one male and one female. If you were asked to definitively determine which is the male and which is the female in each of these examples, how would you do it? What sort of information would you need? Basically, how do we distinguish males from females?

Points to Ponder

Is there one unifying characteristic that sets males and females apart, in all organisms—plants, animals, protists, etc.—that have male and female individuals?

 

  1. Image "Golden Orb-weaver and suitor" by Graham Winterflood. Shared with CC-BY-SA 2.0 license. ↵
  2. Image "Hippocampus japapigu" by Hiroyuki Motomura. Shared with CC-BY 4.0 license. ↵
  3. Image "Marsh fritillaries (Euphydryas aurinia) mating" by Charles J. Sharp. Shared with CC-BY-SA 4.0 license. ↵
  4. Image "Grass snakes (Natrix natrix) mating coil" by Charles J. Sharp. Shared with CC-BY-SA 4.0 license. ↵

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Introduction to the Evolution & Biology of Sex Copyright © by Katherine Furniss and Sarah Hammarlund is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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