Sexual dimorphism - Wikipedia
With a little imagination, one can readily picture male trilobites crawling along the ancient sea floor, brandishing an array of eye-catching bodily decorations perhaps in a variety of bold colors all done in an attempt to gain the notice of available females. Such behavior, however, is still highly speculative, and pushes us to examine an equally compelling question: if the males of the trilobite class exhibited such ornate ornamentation, then have we possibly misclassified, or at least misidentified, the females of the species?
Judging by the material presented within the fossil record, such a conclusion seems to be a distinct possibility. But while we currently know little about sexual dimorphism in trilobites, there is still hope that we may eventually garner additional knowledge on the subject.
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Each year more trilobites that exhibit soft-body part preservation are being discovered in various locales around the globe. And with improved preparation techniques revealing previously unknown details of trilobite anatomy, perhaps one day we will uncover evidence that will shed additional light upon this most basic of trilo-topics.
The possibility exists, however, that we will never learn how to differentiate male and female trilobites. The world will probably keep spinning even if we don't.
Hen's teeth… unicorn droppings… trilobite eggs… all apparently stuff of myth, mirth and legend. Make no mistake about it; trilobite eggs did indeed exist! The fact is that evidence of trilobite eggs has long been sought yet never previously seen in the fossil record. Some scientists have even referred to any such irrefutable indicator of trilobite reproductive behavior as the Holy Grail of invertebrate paleontology. Advanced search.
Human sexual dimorphism--a sex and gender perspective.
Skip to main content. Search My Account Login. Latest Research and Reviews Research 03 July Whole-animal connectomes of both Caenorhabditis elegans sexes Quantitative connectivity matrices or connectomes for both adult sexes of the nematode Caenorhabditis elegans are presented that encompass all connections from sensory input to end-organ output across the entire animal. Nature , Research 03 June Open Access Sex-specific association between gut microbiome and fat distribution The gut microbiome has been reported to be associated with obesity; here, the authors show that there are sex-specific differences in the relationship between gut microbes and abdominal obesity.
Nature Communications 10 , Lenz , Lindsay A.
Sexual Dimorphism / Trilobite Eggs
Pickett , Christopher L. McCarthy Scientific Reports 9 , Reviews 13 February The neural mechanisms and consequences of paternal caregiving Recent years have seen a growing interest in the neurobiological basis of paternal caregiving.
Nature Reviews Neuroscience 20 , News and Comment Research Highlights 26 February Parental controls The sexually dimorphic responses of male and female mice to their young are regulated by the activity of a specific population of neurons in the medial amygdala. Research Highlights 21 May Some like it hot — sex determination in turtles A recent study in Science reports the mechanism by which temperature affects sex determination in the red-eared slider turtle, Trachemys scripta elegans.
Nature Reviews Genetics 19 , Comments and Opinion 03 November Incorporating sex as a biological variable in neuroscience: what do we gain? See Article History.
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Learn More in these related Britannica articles:. Certain tissues are set aside for the production of sexual reproductive cells, male or female as the case may be. Whether they are testes or ovaries or, as in some animals and plants, both together in the…. The differential effects on the growth of bone, muscle, and fat at puberty increase considerably the difference in body composition between the sexes.
Boys have a greater increase not only in stature but especially in breadth of shoulders; girls have a greater relative….