Not all species share a common sex-determination system. In most animals, including humans, sex is determined genetically, but in some species it can be determined due to social, environmental or other factors. For example, Cymothoa exigua changes sex depending on the number of females present in the vicinity.
The existence of two sexes seems to have been selected independently across different evolutionary lineages (see convergent evolution). The repeated pattern is sexual reproduction in isogamous species with two or more mating types with gametes of identical form and behavior (but different at the molecular level) to anisogamous species with gametes of male and female types to oogamous species in which the female gamete is very much larger than the male and has no ability to move. There is a good argument that this pattern was driven by the physical constraints on the mechanisms by which two gametes get together as required for sexual reproduction.
Plant reproductive morphology is concerned with the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction.
Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants (green algae, mosses, liverworts, hornworts, ferns and gymnosperms such as conifers) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwin's theories of natural selection utilized this work to build his theory of evolution, which includes analysis of the coevolution of flowers and their insectpollinators.
"Even a moderate Republican such as Sen ... Filipovic notes that "caustic tweets…. ... As long as we expect women to be accommodating while rewarding male leaders who are aggressive and even cantankerous, 'temperament,' exemplified by some impolitic tweets, will remain an embarrassing and transparent justification for keeping women out of power." .
PUBLISHED ON FEB 22, 2021 11.30 PM IST... A decision in this regard was taken during a special review meeting held at the MCG’s Sector 34 office on Monday. At the meeting, the status of all MCG projects costing more than ₹5 crore was reviewed ... In addition, MCG had also decided to build a hostel for accommodating over 100 male and female athletes ... ....
Alicia Petska ...The new fire station, built on the same RaleighCourt site that the prior station occupied, offers more space to accommodate facilities for male and female firefighters and is better laid out for the size of today's fire engines. The building officially went into service Tuesday ... .
MASSILLON CommQuest's adolescent inpatient and intensive outpatient services are moving to Massillon... The facility for teens 14 to 19 was housed on Faircrest Street in Canton Township ... The co-ed unit will allow for five girls and 11 boys, Hochadel said, but it can easily be switched to accommodate more females and less males ... On Twitter ... .
He said the new location has accommodated a total of four people since it opened ... The space for the shelter includes four single rooms, and then one larger room that can accommodate two to three people ... We can accommodate males and females, because we have individual rooms.
Can’t we support transgender youth in better ways than making extraordinary sports accommodations for a small percentage of society? If exclusively male or female teams have to admit those transitioning, the spirit of 1972’s Title XI legislation – to provide equal opportunity to compete in sports – will be completely turned on its head.
DPWH/ MANILA BULLETIN ... Villar added that the facility consists of a “2-storey accommodation building, 2-storey infirmary building, laundry area, male and female toilets, materials recovery facility (MRF) and provision of generator set and transformer.” ... .
The smallest known reptile in the world can fit on your fingertip ... Before 2012, biologists didn't know it existed ... +10 ... 1 ... While the male was just over 2 centimeters long -- a bit over ¾ inch -- the female was 2.89 centimeters, over an inch long. The females are likely larger than the males to accommodate the eggs they lay, Glaw and Hawlitschek said ... .
... and the Biden administration to limit the participation of transgender girls and women who have experienced all or part of male puberty (which is the scientific justification for separate sex sport), while accommodating and honoring their sports participation in other ways.
Over the last two weeks in January, Woods and the shelter staff were able to secure funding to run the emergency shelter, clean out the building on Washington Street that use to be home to the women’s shelter and hire the male staff needed to run the overnight accommodations.
Devon and Cornwall Police said Ismail, who worked for a care group in London supporting vulnerable young adults, had a specific interest in working with young male gang members. The court heard she was a deputy care manager providing supported accommodation for teenagers and young adults, and became Nixon's key worker in 2018 ... He added ... .
The woman has been offered other accommodation and arrangements have been made for her support, police said. Images of another male, also thought to be a teenager who police wish to speak to in connection ...