Questions involving the study of sex and reproduction, mating systems, sexuality, sex determination, gender, the evolution of sex, and other topics in the context of sex.

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1answer
33 views

How can I determine the gender of a tree seedling?

I would like to plant some home grown female mulberry trees in a circle, with a male plant in the center for pollination. How do I determine the gender of a tree seedling? I know it's possible, ...
3
votes
1answer
275 views

Do hormones make men think of sex?

I remember hearing a saying that goes like "men think of sex every 7 minutes (or seconds?)". I take this saying to mean that men have sex related thoughts more often than women. I'm interested if ...
3
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0answers
36 views

Electrodes in the brain and 'repetitive orgasms' [on hold]

The advent of chlorpromazine in 1955 put an end to one of the more bizarre chapters in American psychiatry.$^1$ Dr. Robert Heath implanted wires or delivered injections of acetylcholine (a ...
0
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1answer
33 views

Two-fold cost of sex and r/K selection theory

This article cites a bunch of articles (I haven't been through them) that the effect of the two-fold cost of sex is "reduced" in stable environment or in K-selected environment. It says: [..] the ...
2
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3answers
72 views

Does any animal species have two sexes and more genders?

Does it exist any animal species that have two sexes and a kind of different internal diversification in two genders or more? I mean no something like different-task-based diversity but something ...
2
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1answer
33 views

Advantages of bisexual reproduction over asexual one toward species promotion? [duplicate]

Are there any advantages of bisexual reproduction over asexual one towards species conservation and promotion? Do animals that have two or more sexes have more chances to reproduce? Does anybody had a ...
6
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2answers
199 views

How Sex Evolved ? and when?

As I know evolution comes bit by bit mutation by mutation How sex evolved which requires a major change in at least two individuals one to become male and one to become female ? When that happened ...
1
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2answers
144 views

Were early human beings (about 100 - 200 K years ago) far more promiscuous than we are now?

I found that many friends of mine are quite easy in sexual relationship. Ex, I knew a lot of girls went to the night club & met a stranger & brought home to sleep with him even she had never ...
1
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1answer
56 views

Does recombination increase the additive genetic variance for fitness?

On this article, first column, eighth line of the introduction: By bringing together favourable alleles from different chromosomes, sex and recombination increase the additive genetic variance for ...
2
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1answer
48 views

Evolution from Mating types to different sexes

Imagine a lineage of multicellular organisms that had mating types and evolved their mating types into sexes. What are the possible mechanisms that might have brought this lineage to evolve sexes from ...
5
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1answer
77 views

Hill-Roberston effects and effective population size

From this article, first page, middle of the second column: Even if harmful alleles do not become fixed, they can still reduce the efficacy of selection on neighbouring loci through a process ...
1
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1answer
48 views

What is the current theory of sexual orientations in Biology?

What is the current explanation of what causes the different sexual orientations in humans.
1
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1answer
23 views

Could mating/recombination be responsible for evolution of entirely novel features?

The diploid chromosomal architecture is rather interesting. For example, because of diploidy we Humans have to mate. Of course in that sense, because diploid organisms often have mate, this has led to ...
4
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1answer
101 views

Sexual Differentiation in Monoecious plants with unisexual flowers

In monoecious plants having unisexual flowers (eg Zea Mays, Ricinus Communis etc), there must be some mechanism as to produce two sexually distinct flowers from the same genotype. Since both the type ...
0
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0answers
36 views

Why do gay people exist? [duplicate]

I mean no disrespect to gay people - this question isn't intended to be judgemental or homophobic at all. I also know nothing about biology so please excuse my ignorance if this question ends up ...
1
vote
1answer
45 views

Pseudosexual reproduction

Research projects with artificial life generally use creatures that are haploid. The offspring randomly inherit some genes from one parent, and some genes from the other parent. Q1: Are there any ...
2
votes
2answers
121 views

Can diploidy evolve in absence of sexual reproduction?

Theoretical question Can diploidy (or polyploidy) evolve from a haploid lineage in the absence of sexual reproduction ? For what theoretical reason? How can such evolution take place? Empirical ...
5
votes
2answers
99 views

Can you tell the sex of a white willow when it's not flowering?

Can you tell whether a salix alba tree will produce male flowers or female flowers by looking at it, touching it or generally using your unaided senses? If not, is there any way to do that without ...
2
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2answers
235 views

How to know if a woman is fertile without actually making her pregnant?

How to know if a human female is fertile (can give birth to child in future) without making her pregnant? Any signs, tests?
4
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0answers
125 views

Genetic expression in interspecific hybrids

Referring to interspecific hybrids, I have the following two questions:- Quoting from wikipedia:- The offspring of an interspecific cross are very often sterile; thus, hybrid sterility ...
0
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1answer
73 views

The probability of indirect human fertilization (follow-up)

This question is a follow-up to this one. I've been wondering how small that probability is. As we all know, "safe" sex, that is (correctly) using a condom and all that, isn't perfectly safe. So, in ...
3
votes
1answer
4k views

What is the standard deviation of adult human heights within sexes?

The wikipedia article on human height reports mean height for many different countries by sex but it does not report standard deviations. What is the standard deviation of adult human heights within ...
1
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3answers
506 views

Can animals, like monkeys, be homosexual?

I heard that some monkeys can be homosexual? a friend of mine was saying that he saw a male monkey having sex with another male monkey in the zoo, I honestly didn't believe him, I think he just got ...
2
votes
1answer
183 views

How do fully dioecious plants determine sex?

I know that a minority of plants are fully dioecious, with adult plants producing either only male or only female flowers. When is this sexual differentiation determined? Is the seed of such a plant ...
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0answers
156 views

Does sexual arousal inhibit functions of prefrontal cortex in human females as well as males?

I've read somewhere, that when a human male experiences sexual arousal, his prefrontal cortex and, hence, his ability to reason and make rational decisions, is being heavily inhibited. Sounds pretty ...
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0answers
52 views

Why did animals evolve genders? [duplicate]

The majority of animals have two genders, and both are needed in reproduction. It seems like it would be more advantageous for creatures to be hermaphrodites, since they could mate with any member of ...
1
vote
1answer
134 views

are female bonobos “always” pregnant?

Given that bonobo chimps are more sexually active then humans, are the females almost always pregnant? if not how not? also are they so sexually active in the wild as well or is it just in captivity? ...
11
votes
1answer
270 views

How do members of cryptic species know who to mate with?

According to Wikipedia: In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each ...
13
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1answer
391 views

How do porcupines keep from pricking each other while mating?

How do porcupines keep from pricking each other while mating? It seems like they would constantly be scratching each other.
4
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1answer
108 views

How does sex differentiation work in Paracerceis sculpta, the sexually tetramorphic isopod?

Paracerceis sculpta is a marine isopod species known for its unusual reproductive strategy: female: medium-sized; lives in harems run by an α male α male: large; keeps a harem of females β male: ...