Episode 25: Dr. Ryan Earley and “Why are there males”?

On this week’s episode Kelly and Zach talk to Dr. Ryan Earley about why so many species reproduce sexually rather than asexually. We then talk to Elizabeth Lee and Robert Denton, whose #SciFund projects focus on animals with uncommon reproductive systems.


Dr. Ryan Earley and “Why are there males?”

Two-fold cost of sex

Red Queen Hypothesis (check out this great book for more information on this topic)

Court Jester Hypothesis


Mangrove rivulus

Video of mangrove rivulus jumping from the lab of Dr. Gibbs

Mangrove rivulus hangs out in logs


Kin selection

Genetic drift

Founder population/founder effect

Scientific article: Best of both worlds? Association between outcrossing and parasite loads in a selfing fish 

SciFund project bringing Daphnia back to life to study long-term effects of pollution

Elizabeth Lee and endocrine disrupters

Endocrine disrupters

Ethinyl estradiol disrupts sexual selection in sand gobies

Intersex smallmouth bass in the Potomac

Ethinyl estradiol

Liz’s SciFund project page

Robert Denton and unisexual salamanders

Mole salamanders

Rob’s SciFund project page

2 thoughts on “Episode 25: Dr. Ryan Earley and “Why are there males”?

  1. Pingback: 9 Days and Counting! « redrhizos

  2. Morris Keesan

    You covered the issue of sexual vs. asexual reproduction, but an interesting question that wasn’t addressed is “Why are there males?” I understand the benefits of gene-sharing, conferred by sexual reproduction, but why does this require sexual dimorphism? One can easily imagine a system where two individuals can share genes without having to be of different sexes. Ursula K. Le Guin envisioned one such possibility in her 1969 novel The Left Hand of Darkness, where individuals can change gender, but especially if we don’t restrict ourselves to viviparous reproduction, why does there even have to be gender? Why does one partner have to contribute the “egg”, and the other the “sperm”? Why not have two equivalent (non-gendered) haploid cells which combine to form a merged offspring (and, speaking of haploid cells, it took me a while to figure out that the word you were tossing around was “ploidy”; a mention of the words “haploid” and “diploid” in the explanation would have helped.)? This ought to double your chances of finding a mate.


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