Bryan Lawlor
bryan-lawlor.bsky.social
Bryan Lawlor
@bryan-lawlor.bsky.social
I'm happy to share the info! I think it helps to be literate about sex in other animals and plants.

Gender is a different discussion - I leave it to psychology. My focus will be to share what we know about biological sex. :-)
March 28, 2025 at 5:20 AM
This constitutes the core scientific definition of the sexes, grounded in our understanding of how reproduction works.
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March 27, 2025 at 5:51 PM
March 27, 2025 at 5:51 PM
The answer: the relative size and function of their gametes. All sexed species produce two types of gametes.

The male gamete is smaller and optimized for mobility. The female gamete is a larger and more complete cell. Reproduction can occur when one of each meet.
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March 27, 2025 at 5:51 PM
It depends. If they break a window to steal a loaf of bread, they should go to prison for 20 years. It makes for a great Broadway musical.
March 26, 2025 at 11:56 PM
Climate change is a concern for these species. Many have begun to nest earlier and earlier in the year to preserve the sex ratio. While the pivotal temperature is heritable, it is expected that climate change will outpace the ability of many animals to adapt, and some will likely go extinct.
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March 26, 2025 at 7:54 PM
This follows one of three patterns, depending on species. In Pattern Ia, warmer temperatures favor female development, and in Pattern Ib, it is the reverse. In Pattern II, there’s a middle sweet spot that favors male development, and females develop at warmer or cooler temperatures.
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March 26, 2025 at 7:54 PM
Instead of genetics, incubation temperature determines their sex during the middle 1/3 of development, called the thermosensitive phase. Once this phase is over, sex is irreversible and the critter will develop testes or ovaries.
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March 26, 2025 at 7:54 PM
Most fungi cycle through diploid and haploid stages, and can reproduce in some way in either stage.
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March 25, 2025 at 10:55 PM
Heterothallic species have mating types which determine compatibility, mostly avoiding the pitfalls of self-fertilization. In some systems, this may resemble a male-female dichotomy, while in others, each individual is compatible with >50% of the population.
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March 25, 2025 at 10:55 PM
Homothallic species are not picky about their sexual partners and frequently self-fertilize. While this strategy is bad for genetic diversity, it can be helpful in high stress environments.
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March 25, 2025 at 10:55 PM
Wow, that's fascinating! Ginkgo is truly a special plant, one of my favorite trees.

I found a video of their giant sperm swimming. I wonder why they are so large?
youtu.be/QqWrlWUoRBU?...
THE SEA IN THE SEED-Sperm of Ginkgo biloba and Reproductive Evolution in Plants-
YouTube video by NPO法人科学映像館
youtu.be
March 25, 2025 at 10:45 PM
It's worth noting that plants evolved a two-sex system independently from animals. Eukaryotes evolved sexual reproduction about 1.5 billion years ago, alongside mitochondria and the cell nucleus. However, the two-sex system ("anisogamy") evolved much later. Fungus do not share this system.
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March 24, 2025 at 8:30 PM
Something different about plants is the sperm cells, found in pollen. Unlike animals, the cells don't have propulsive tails (flagella). Instead, pollen grains develop a pollen tube to guide the sperm to the egg cells.
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March 24, 2025 at 8:30 PM
Plants like this are called monoecious ("one house"). Without sex chromosomes, their sperm and eggs have the same mix of genetics.

Fewer plants do have a single sex each. These are called dioecious ("two houses"). These may have sex chromosomes that determine the sex of an individual plant.
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March 24, 2025 at 8:30 PM
In some animals, the Y or W chromosome has disappeared entirely, so sex is determined by whether there are one or two of the remaining sex chromosome.
XX = F, X = M,
ZZ = M, Z = F.
March 23, 2025 at 10:55 PM
The W chromosome is like a female version of the Y chromosome. Both of these are degenerate, because they doesn't have a pair to swap/recombine alleles with during meiosis. That means evolution "sees" the chromosome as one indivisible unit, and deleterious mutations accumulate over time unchecked.
March 23, 2025 at 10:55 PM
Drones live only for a single purpose: to mate with a queen from a different hive.

They fly out to a mating site called a "drone congregation area" which will attract a virgin queen. The queen will mate with a dozen or so drones, who explode upon delivering their payload.

Honey. Nut. Cheerio.
March 22, 2025 at 2:01 PM
So females have a mother and father, but males only have a mother. (They do have a grandfather, though).

Queens are females that are fed royal jelly as larvae, which makes them fertile and live longer.
March 22, 2025 at 2:01 PM