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how did evolution create male and female

how did evolution create male and female插图

This implies that when humans transitioned to farming, changes in the human body (like weaker bones) reflected that adaptation. Maleand femalebodies, in turn, evolvedto be more similar to each other because of farming — or so goes the theory.

How did the first sexually reproducing organisms evolve?

But the first sexually reproducing organisms were a form of single-celled bacterium which thus had no organs at all. As sexually reproducing organisms evolved into multicellular forms and their cells began to specialize, some cells began specializing for male and female reproductive function, both evolving at the same time, by small gradual steps.

Could heredity provide evidence for the first stages of Sex Evolution?

Research from the University of Pittsburgh published in the Nov. 20 edition of the journal Heredity could finally provide evidence of the first stages of the evolution of separate sexes, a theory that holds that males and females developed from hermaphroditic ancestors.

Do evolutionists answer questions like “where did males and females come from?

When pressed to answer questions such as, “Where did males and females actually come from?,” “What is the evolutionary origin of sex?,” evolutionists become silent.

How did mammals evolve to have fixed genders?

Thus, the very first mammals were already genetically evolved to have fixed genders, and already had matched gendered organs in place, as those organs had evolved long before (from fish through reptiles).

What happens when you are isogamous?

But if you’re isogamous, you’re exchanging same-sized gametes instead of sperm and eggs. So to keep mitochondria in check many organisms kill the ones from their mates.

How many sexes do mushrooms have?

Some organisms do expand their sexual options by having many sexes — 100 for some pond-swimming protozoans. Mushrooms use 30,000 and can mate with any but their own. Oddly, however, most sexual beings have just two sexes — the loneliest number when it comes to finding a mate.

What are the little engines that help us convert food to energy?

One leading theory goes back to the bizarre nature of certain machinery we all carry around in our cells — little engines known as mitochondria that help convert food to energy.

When was sex invented?

That’s because sex was invented before heterosexuality — before males or females, for that matter. The first sexual beings to emerge perhaps 2.5 billion years ago were what biologists call isogamous — which is a little like being gay, except everyone is somewhere between male and female.

Can mitochondria mutate?

And while they seem to be working for us, they have no binding contract to continue to do so. Because they carry their own DNA, they can mutate, the scientists say, so you could in theory get a new strain of mitochondria that’s very good at replicating, but not very good for you.

Is pickiness a paradox?

Such pickiness is an enormous paradox, says Laurence Hurst, a biologist at the University of Bath in England. Without sexes, you wouldn’t have to limit your choice of a mate to half the population. Anyone would be fair game.

Who is Faye Flam?

Faye Flam is a Bloomberg Opinion columnist and host of the podcast "Follow the Science."

WHY SEX?

Why, then, does sex exist? In his 2001 book, Evolution: The Triumph of an Idea, Carl Zimmer admitted:

What is the process of sporulation?

A single parent is all that is required. Sporulation (the formation of spores) is one method of asexual reproduction among protozoa and certain plants. A spore is a reproductive cell that produces a new organism without fertilization.

What is asexual reproduction?

Asexual reproduction is the formation of new individuals from cells of only one parent, without gamete formation or fertilization by another member of the species. Asexual reproduction thus does not require one egg-producing parent and one sperm-producing parent.

How can DNA be damaged?

DNA can be damaged in at least two ways. First, ionizing radiation or mutagenic chemicals can alter the genetic code. Or, second, a mutation can occur via errors during the replication process itself. Most mutations are deleterious (see Cartwright [ 22] ).

What is the survival of the fittest?

As it turns out, the common “survival of the fittest” mentality cannot begin to explain the high cost of first evolving, and then maintaining, the sexual apparatus. Sexual reproduction requires organisms first to produce, and then maintain, gametes (reproductive cells-i.e., sperm and eggs).

Why is sexual reproduction so difficult?

The difficulty is that sexual reproduction creates complexity of the genome and the need for a separate mechanism for producing gametes. The metabolic cost of maintaining this system is huge, as is that of providing the organs specialized for sexual reproduction (the uterus of mammalian females, for example).

What are the organisms that evolved from amoebas?

iology texts illustrate amoebas evolving into intermediate organisms, which then give rise to amphibians, reptiles, mammals, and, eventually, humans. Yet, we never learn exactly when or how independent male and female sexes originated.

Why do stags have antlers?

Stags use their antlers to fight other stags over mates; the buck with the biggest and strongest antlers is likely to have his choice of mate. In humans, those sexually differentiated traits exist but are much more subtle. (For example, females tend to be shorter than males of the same population.)

What is the inverse analysis?

The Inverse analysis —There’s so much we don’t know about how male and female humans evolved. Researchers were able to debunk a longstanding hypothesis about natural selection and farming through genetic analysis. Perhaps the answers will be found in the most complex set of instructions on earth: the human genome.

Why did males and females evolve to be more similar to each other?

Male and female bodies, in turn, evolved to be more similar to each other because of farming — or so goes the theory.

Who is Audrey Arner?

How they did it — Co-author Audrey Arner is a research technologist at Penn State University. She tells Inverse her team used data from the UK Biobank, a huge database comprised of genetic and health information, to “identify genetic variants in the genome that are differentially associated with trait variation between females and males for five different body size and shape phenotypes.”

Do deer have antlers?

For example, while both male and female deer have antlers, stags and bucks (male deer) have antlers that are much bigger than the females. Stags use their antlers to fight other stags over mates; the buck with the biggest and strongest antlers is likely to have his choice of mate.

What is the function of sex chromosomes in plants?

Sex chromosomes in these plants have two loci-or positions of genes on a chromosome-one that controls sterility and fertility in males and the other in females. Offspring that inherit both fertility versions are hemaphrodites capable of self-breeding. Plants that possess one fertility and one sterility version become either male or female.

What is the theory of separate sexes?

20 edition of the journal Heredity could finally provide evidence of the first stages of the evolution of separate sexes, a theory that holds that males and females developed from hermaphroditic ancestors. These early stages are not completely understood because the majority ...

Why are early stages of heredity not fully understood?

These early stages are not completely understood because the majority of animal species developed into the arguably less titillating separate-sex state too long ago for scientists to observe the transition. Research from the University of Pittsburgh published in the Nov. 20 edition of the journal Heredity could finally provide evidence ...

Do strawberry plants have hermaphrodites?

For the current study, Ashman and Pitt postdoctoral research associate Rachel Spigler worked with a wild strawberry species in which the evolution of separate sexes is not complete, so hermaphrodites exist among male and female plants.

Can a single sex plant reproduce?

Plants that possess one fertility and one sterility version become either male or female. Those with both sterility versions are completely sterile, cannot reproduce, and, thus, die out. The single-sex plants breed not only with one another but also with hermaphroditic plants and pass on the mutation, which can result in single-sex offspring. ...

Can males mate with females?

Mar. 20, 2019 — In nature, males eager attempts to mate with females can be so extreme that they will harm females. Such negative impact of mating interactions has been suggested to promote the emergence of new ...

Who is Tia Lynn Ashman?

However, Tia-Lynn Ashman, a plant evolutionary ecologist in the Department of Biological Sciences in Pitt's School of Arts and Sciences, documented early separate-sex evolution in a wild strawberry species still transitioning from hermaphroditism.

What are the two branches of amniotes?

Amniotes split in two branches, Synapsida and Sauropsida. The synapsida group eventually gave rise to modern mammals, while the sauropsida group eventually lead to modern day turtles, reptiles and birds.

What would happen if the sexes developed at the same time?

If the sexes developed at the same time over millions of years, they would have had to exist for the same time. They could not have passed it on to their offspring. I love the way the Evolutionist, hurl their numbers of 1, 10, 100, 200, million years around. They never bring up probability numbers tho. So sad..

Why are mutations bad for organisms?

For people both with both body parts, that is the result of mutations that are generally bad for the organism that tend to be the result of the way certain genomes interact with certain environmental factors. In nature they would be filtered out and the ones that tend to help the organism survive long enough to reproduce in that specific environment will not be filtered out and will reproduce those genes and outcompete the organisms that don't have those genes.

Did sexual reproduction begin without sexually distinct organs?

They didn't. Sexual reproduction began without sexually distinct organs, and then such organs evolved in tandem over time. Many plants, for example, are hermaphroditic: each plant has both male and female sexual organs. But the first sexually reproducing organisms were a form of single-celled bacterium which thus had no organs at all. As sexually reproducing organisms evolved into multicellular forms and their cells began to specialize, some cells began specializing for male and female reproductive function, both evolving at the same time, by small gradual steps.

Is the evolutionary distance between humans and reptiles the same as the evolutionary distance between humans and modern birds?

The evolutionary distance between humans and modern reptiles is just as large as the evolutionary distance between humans and modern birds.

What mammals have Y chromosomes?

By studying samples from several male tissues -- in particular testicles -- from different species, the researchers recovered the Y chromosome genes from the three major mammalian lineages: placentals (which include humans, apes, rodents and elephants), marsupials (such as opossums and kangaroos) and monotremes (egg-laying mammals, such as the platypus and the echidna, a kind of Australian porcupine). In total, the researchers worked with samples from 15 different mammals, representing these three lineages, as well as the chicken, which they included for comparison.

Why did scientists eliminate all sequences common to both sexes?

Instead of sequencing all Y chromosomes, which would have been a " colossal task " according to Diego Cortez, researcher at CIG and SIB and main author of the study, the scientists " opted for a shortcut ." By comparing genetic sequences from male and female tissues, they eliminated all sequences common to both sexes in order to keep only those sequences corresponding to the Y chromosome. By doing so, they established the largest gene atlas of this " male " chromosome to date.

What is the difference between a man and a woman?

Man or woman? Male or female? In humans and other mammals, the difference between sexes depends on one single element of the genome: the Y chromosome. It is present only in males, where the two sexual chromosomes are X and Y, whereas women have two X chromosomes. Thus, the Y is ultimately responsible for all the morphological and physiological differences between males and females.

How many genes does the X have?

It then progressively shrank to such an extent that, nowadays, it only contains about 20 genes (the X carries more than one thousand genes).

When did the sex determining gene appear in placentals?

The study shows that the same sex-determining gene, named SRY, in placentals and marsupials had formed in the common ancestor of both lineages around 180 million years ago . Another gene, AMHY, is responsible for the emergence of Y chromosomes in monotremes and appeared some 175 million years ago.

When did sex genes first appear?

They have established that the first " sex genes " appeared concomitantly in mammals around 180 million years ago.

When did sex determine genes?

First sex-determining genes appeared in mammals some 180 million years ago . The Y chromosome, which distinguishes males from females at the genetic level, appeared some 180 million years ago. It originated twice independently in all mammals.

how did evolution create male and female
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