Reproductive cycles

[lifesagift]

So why is gestation 9 months?

[BrianSoddingBoru4]

So why is gestation 9 months?

Why should it be anything else? Gestation periods cover a very wide range, depending on the organism. Humans have a 9-months gestation period because that is what works for humans.

Instead of asking these questions here, perhaps you could pick up a book on basic evolutionary biology. I'm sure you could find one with short words and colourful pictures.

Boru

[lifesagift]

So why is gestation 9 months?

Why should it be anything else? Gestation periods cover a very wide range, depending on the organism. Humans have a 9-months gestation period because that is what works for humans.

Instead of asking these questions here, perhaps you could pick up a book on basic evolutionary biology. I'm sure you could find one with short words and colourful pictures.

Boru

I ask a question like why is a lemon yellow, and you reply "because it is", and I'm at fault?!

[BrianSoddingBoru4]

Why should it be anything else? Gestation periods cover a very wide range, depending on the organism. Humans have a 9-months gestation period because that is what works for humans.

Instead of asking these questions here, perhaps you could pick up a book on basic evolutionary biology. I'm sure you could find one with short words and colourful pictures.

Boru

I ask a question like why is a lemon yellow, and you reply "because it is", and I'm at fault?!

Yes, you're at fault for asking idiotic questions.

And enough with the private messages. If you want to talk to me, do it out here. If you don't want to talk to me, thank you in advance.

Boru

[lifesagift]

No question is idiotic... any quest for knowledge is surely valid? and only idiotic in your 'superior' mind?

Feel free to avoid the thread, and let others discuss..

[Whateverist]

More importantly, why are some aphids born pregnant with their granddaughters?

Some aphids have telescoping generations, that is, the parthenogenetic, viviparous female has a daughter within her, who is already parthenogenetically producing her own daughter.

http://en.wikipedia.org/wiki/Aphid

Just saying I could do with about 10,000 or so fewer aphids.

Geez, I've heard of kids having kids but embryos having embryos? Madness.

[Heywood]

Why should it be anything else? Gestation periods cover a very wide range, depending on the organism. Humans have a 9-months gestation period because that is what works for humans.

Instead of asking these questions here, perhaps you could pick up a book on basic evolutionary biology. I'm sure you could find one with short words and colourful pictures.

Boru

I ask a question like why is a lemon yellow, and you reply "because it is", and I'm at fault?!

Lemons are yellow because the skins contain xanthophyll and carotene pigments. Those pigments reflect yellow light and absorb the rest. Hence when you view a ripe lemon, it is yellow.

I do not know why human gestation is 9 months. I doubt the question could be answered as easily as why are lemons yellow.

[The Grand Nudger]

Just saying I could do with about 10,000 or so fewer aphids.

If you're into biological controls....you can buy bulk ladybugs, lacewings, soldier beetles, or syrphid fly. There are some species of parasitic wasp that are even more effective....but that might be a step too far into cruelty, lol. Other times, managing any ants will solve your aphid issue (if they;re being tended). In prevention, you could manage nitrogen levels down to their bare minimum (high N favors aphid developement). Silver muclhes are, apparently, a legitimate repellent for reasons unknown but statistically present - and of course viscious culling, pruning...and believe it or not just spraying the plants vigorously with water will help control them (it;s rare that a dislodged aphid returns to the roost. They don't survive long on the ground.

All that said, if nothing else works. Burn your garden/lawn to the ground and start over....lol. Fucking aphids.

(just tossing all of that out there in case you'd been looking - just poisoning them is also an option...lol. That'd be what I would do, just poison the shit out of them and anything they ate or that ate them. Systemics. There are plenty of bugs in the world, they'll be back.)

[Anomalocaris]

Why are our reproductive cycles so short?
Given that the solar system is 4.6 billion years old... why do we produce offspring in just 0.75 of a year? and not 170 years?

Why is a day 24 hours and 3546.13 years?


The gestation period is a compromise between several competing demands: Survival of the mother, survival of the fetus and survival of the infant. They each conflict with the others. The survival of the mother demands the shortest gestation period, the smallest demand upon metabolism, and the smallest fetus at moment of birth. The survival of the fetus demands substantial metabolic contribution from the mother, and the survival of the infant demand considerable size and level of development at birth without killing the mother-ie lengthy gestation. 8-9 month was apparently the best compromise between survival of the mother and survival of the fetus and infant in common ancestor of the great apes. Great apes all share roughly the same gestation period of 8-9 months

The reason why human gestation is 9 and half months is simply that during the 6 million years or so since human ancestors branched off of other great apes, there had not been sufficient selection pressure, or not enough time for the pressure to act, to change our gestation period substantially from our common ancestors with the apes.

[Jenny A]

Like everything else concerning biology there are physical constraints. For gestation the greatest physical constraint on how fast a gestation period can be is the ultimate size of the newborn. Starting from a single cell, it simply takes longer to grow larger organisms. Thus in general larger animals have longer gestation periods. However animals that live concealed underground or raise their young in nests or burrows give birth to initially smaller and less developed offspring and therefore have shorter gestation periods than animals who raise their offspring out in the open. Marsupials who raise their young in pouches for a extended development period after birth have extremely short gestation periods.

There are some other factors. Some species breed during one part of the year and then the embryo lies dormant for some time before resuming growth. These anomalies tend to result in offspring born at the peak season for feeding the particular species young. For a general discussion see:http://www.britannica.com/EBchecked/topi.../gestation; For a comparative chart of mammalian gestation periods see: http://www.vaughns-1-pagers.com/biology/...eriods.htm

Beyond these factors, evolution works on random mutations to existing animals rather than sculpting animals from whole cloth. Thus chance plays a role.

---

Just saying I could do with about 10,000 or so fewer aphids.

If you're into biological controls....you can buy bulk ladybugs, lacewings, soldier beetles, or syrphid fly. There are some species of parasitic wasp that are even more effective....but that might be a step too far into cruelty, lol. Other times, managing any ants will solve your aphid issue (if they;re being tended). In prevention, you could manage nitrogen levels down to their bare minimum (high N favors aphid developement). Silver muclhes are, apparently, a legitimate repellent for reasons unknown but statistically present - and of course viscious culling, pruning...and believe it or not just spraying the plants vigorously with water will help control them (it;s rare that a dislodged aphid returns to the roost. They don't survive long on the ground.

All that said, if nothing else works. Burn your garden/lawn to the ground and start over....lol. Fucking aphids.

(just tossing all of that out there in case you'd been looking - just poisoning them is also an option...lol. That'd be what I would do, just poison the shit out of them and anything they ate or that ate them. Systemics. There are plenty of bugs in the world, they'll be back.)

I'm really just complaining to complain.

I stray vigorously with water, soapy water if I'm desperate. I haven't bought ladybugs for years. Mostly they were fun for the kids. Getting the good bugs to stick around is the main problem. I've found planting things that ladybugs like to eat when they can't get aphid is the best long term method for aphid control.