Name: 【TED-Ed】動物生殖器演化，比你想像得複雜多！(The evolution of animal genitalia - Menno Schilthuizen)
Uploaded: 2017-08-06T21:59:58.000Z
Duration: 5 min 36 s

The evolutionary tango of animal genitalia.

If you answered "duck vagina," you'd be right.

若你回答「鴨子陰道」，那你就對了

Although the bird's outward appearance may not strike you as especially odd,

cork-screw shaped contraption to reproduce.

We see similarly unbelievable genitalia in insects,

類似的奇特生殖器同樣存在於昆蟲

Apparently, no organs evolve faster and into more variable shapes

很顯然比起其他器官，生殖器官演進速度更快

Superficially, it makes sense because evolution works via reproduction.

表面看來這不難理解，畢竟演化就是透過生殖進行

When an animal leaves more offspring, its genes will spread.

當一種動物擁有更多後代，基因也隨著傳撥出去

And since genitalia are an animal's tools for reproduction,

而既然生殖器是動物賴以繁衍的工具

any improvement there will have immediate effect.

任何相關的改進都會立即產生效果

And yet, what's the point of having such decorative nether regions?

然而，有著如此花俏的下半身有何用意？

After all, the function of genitalia seems simple.

and a vagina receives it  and delivers it to the egg.

and a funnel-like gizmo on the female should do just fine for any animal.

雌性擁有漏斗型的構造，這樣對任何動物而言照樣能生殖

The penis of a chicken flea, for example, looks nothing like a pipette,

舉例來說，雞蚤的陰莖一點也不像滴管

resembles something you'd find in a Dr. Seuss book.

則形似你在蘇斯博士書裡可能會看到的東西

much more complicated than seems necessary for what they're meant to do.

比起單單為了繁殖還要繁瑣許多

That's because genitalia do more than just deposit and receive sperm.

那是因為生殖器的功用遠多於只是保存精子還有受精

Many male animals also use the penis as courtship device, like crane flies.

許多雄性動物使用牠們的陰莖來求偶，比如大蚊

males have a tiny washboard and scraper on their penis,

which produces a song that reverberates throughout the female's body

It's thought that if female crane flies enjoy this unusual serenade,

人們猜想要是母大蚊喜歡這首奇特的小夜曲

they'll allow the male to father their offspring.

This way, the genes of the most musical penises spread,

這樣看來，保有最具音樂性陰莖的基因得以延續

leading to rapid evolution of insects' phalluses.

Similarly, some beetles have two little drumsticks on either side of the penis.

類似的還有某些甲蟲在陰莖的兩側會有小鼓槌

During mating, they'll rub, slap, or tap the female with these.

在交配過程，它們會摩擦、拍打、或是敲打母甲蟲

And some hoofed mammals, like rams and bulls,

還有一些有蹄哺乳類動物，像是公羊和公牛

use a whip-like extension on the penis's left side

會運用陰莖左側形似鞭子的延伸物

But how can females really choose between males

if she can only assess them after mating?

又該如何在眾多雄性間做出抉擇？

This is where the power of female adaptation comes into play.

這就是雌性擇偶能力浮出檯面的時候

In fact, insemination is different to conception,

事實上，接了精子並不等於受精

and the female genitalia exploit this distinction.

the vagina contains pockets for separating sperm from different males

設置有口袋可以分放來自不同雄性的精子

這全取決於不同的精子有何優勢

and females controlling their own sperm management

are two reasons why genitalia evolve into such complex shapes.

這是為何生殖器演變成複雜形狀的兩個原因

because genitalia are also where a sexual conflict is played out.

因為生殖器也是交配抗爭上演的地方

A female's interests are best served if she fertilizes her eggs

對於雌性來說，用來源最好的精子使卵受精

and creates genetic variability amongst her offspring.

For a male, on the other hand, this is bad news.

For him, it would be best if a female used his sperm

對雄性而言，最好的情況是牠所有的精子

So we see cycles of adaptation in an evolutionary arms race

我們因而看到在自然選擇淘汰下

Black widow spiders have a disposable penis tip

that breaks off inside the vagina blocking the attempts of his rivals,

會斷裂在陰道內，擋住對手精子前進的道路

and bed bug males bypass a female's genitalia altogether

using a syringe-like penis to inject sperm cells directly into her belly.

繞過母床蝨的生殖器，將精子直接注入腹腔

females have evolved their own countermeasures.

the females have evolved an entirely new set of genitalia

on their right hand flanks where the males usually pierce them.

位於公床蝨通常會刺穿的右腹部

That allows them to maintain the power to filter out unwanted sperm

讓她們保有透過生殖器篩選精子

And duck vaginas are shaped like a clockwise spiral

鴨子的陰道則是順時針的螺旋狀

so that when the male inflates his long, counterclockwise coiled penis into her,

所以當公鴨挺入逆時針的捲曲長陰莖時

all she needs to do  is flex her vaginal muscles

So, genitalia differs so much, not just to fascinate us,

生殖器之所以型式多變，並非為了驚豔他人

they're the result of  a furious evolutionary tango of sex

這些生殖器是透過如此激烈的演化過程而來

that has been going on for millions of years

and will continue for millions  of years to come.

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【TED-Ed】動物生殖器演化，比你想像得複雜多！(The evolution of animal genitalia - Menno Schilthuizen)

apparently

conflict

sensation

instance