[古生物/多圖] 有無人對古代生物有興趣?一齊傾下

744 回覆
742 Like 7 Dislike
2017-04-27 23:54:41
推一推
2017-04-28 08:14:13
啱喘追完,幫推
2017-04-28 09:35:10
有冇人睇過以前明珠台 套史前逃龍
Primeval
好撚好睇

Primeval爛尾呀屌佢
2017-04-28 21:29:34
PS4出過一隻叫Birthdays the Beginning既GAME

玩法係俾個世界你培養的生物出黎,由古生物慢慢養到有人類恐龍出黎真係幾正

仲要有中文版好好玩


太Q版,不了
2017-04-29 11:20:27
比較想知眼呢種感光器官的演化
以前讀developmental biology已經覺得好神奇,complex eye果d直頭想像唔到係點develop出黎
2017-04-29 12:35:22
比較想知眼呢種感光器官的演化
以前讀developmental biology已經覺得好神奇,complex eye果d直頭想像唔到係點develop出黎


趁假期 答下你


係好耐,好耐之前............
有一D單細胞小生物,佢地身上開始有一種感光器官,叫 eyespots (眼點)
佢地只可以感應周圍既光暗
例如呢隻眼蟲藻(學名:Euglena)是生物裡的一個屬,屬於裸藻綱。
佢又唔係動物,又唔係植物。
其名字的來源是因為它們有眼點,它與趨光性有關。





2=眼點

眼點令眼蟲可以走去有光既地方,有趨光性。
跟住眼蟲有葉綠體,會進行光合作用。



-------------------------------------------



後來既生物有多細胞eyepatch,
但平旦既設計,分唔到D光由邊度來,
因為邊度射來,都係sense到咁多光,
你只會知有無光射過來,唔知邊一度射過來

之後有D生物既eyespot有更多既感光蛋白質同發色團,又漸漸進化為一個凹洞,
唔同方向射過來既光,會刺激凹洞 (一個"cup"咁)既一部份,
咁就知道D光邊度射過來了
呢種原始既眼,一開始係原始既無脊椎生物上可見到,
例如原始蝸牛
今日既渦蟲 (Planarian) 上都可以見到


今日既渦蟲 (Planarian) 有 "cup"狀 eyespot,可以略為分到光既方向。

早期既凹洞eyespot都係唔太發達,色素不夠,又唔夠凹,
Feel下周圍光暗都係主要功能,分方向既能力未算好強
到將來色素再多D,再凹D,呢個能力先會變勁

發色團收到可見光,會放出訊號,射去神經系統,多數會去腦部
水母都有神經系統,但無腦部,所以訊號會直接去水母既肌肉

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到左寒武紀大爆發 (Cambrian Explosion) [詳情請睇前面第8頁]
寒武紀(5 億 4100 萬年前 ~ 4 億 8500 萬年前 )時,
大部份生物既門都出現
眼睛發展一日千里,色素更多,形狀更凹,視覺能力更強
漸漸,生物隻眼再凹都無咩用,
因為佢地需要既,
更準確既分光方向能力,同認形物件形狀能力,!
佢地需要隻眼既opening細D

呢種眼,今日可以係鸚鵡螺身上搵到


佢地未有角膜,未有晶狀體,但已經進步唔少

後來眼睛外圍長出更多透明既細胞,幫助折射光線,而且保護眼睛不受感染
至於點解我地眼睛只會收到一部份光? (人類眼睛只會見到︰390 to 700 nm的光)
其中一個好可能既原因,係因為早期生物係水中生物,發展出眼睛去幫助光合作用
而只有部份波長既光,先可以係水中穿透,

所以後來生物既眼,都唔會detect所有既光/電磁波,只揀部份

後來生物既眼就出現埋有晶狀體,幫助集中光線,幫助認獵物,睇環境
更有生物有前後移動晶狀體 / 拉扁推圓晶狀體 既能力,隨時調整focus
發展得更好了
2017-04-29 13:29:12
2017-04-29 17:10:58
多謝你咁快手re我
因為得390-700nm入到水,所以眼先detect到呢個range真係第一次聽
不過堆動物上到岸又develop左唔同wavelength的眼,睇到紅外線,紫外線之類
之前睇paper見到,有種蝦的眼可以複雜到睇到plane of polarization of plane-polarized light添,雖然唔知有咩用
一路都覺得眼呢個organ好神奇
2017-04-29 18:24:55

咁岩有化石睇 各位知唔知咩黎?
2017-04-29 18:35:24

咁岩有化石睇 各位知唔知咩黎?


ゴードリセラス <=== Gaudryceras
アンモナイト の一種
<=== Ammonitida (=菊石) 的一種

菊石目
菊石目(學名Ammonitida)是一類已滅絕的頭足類。它們是非常好的指準化石,往往能連結起所在的地層與地質年代。菊石目的近親並非現今外觀相似的鸚鵡螺,反而是八爪魚、烏賊及魷魚等鞘亞綱。
菊石目的化石殼一般呈平旋狀,但也有呈垂直螺旋狀及非螺旋狀。老普林尼稱菊石目為「阿蒙的角」,因其殼的形狀像埃及神話阿蒙所配帶的羊角,其學名亦是以此來取的。[1]其下的屬亦多以希臘文「角」的字根來結尾。

Gaudryceras
一種生活於白堊紀的菊石
2017-04-29 21:38:47
界門綱目科屬種

個SYSTEM 好勁, 有D生物以為近親其實差條街; 相反有D以為無關就其實同源
2017-04-29 21:54:28
lm
2017-04-29 23:56:50

仲有呢個
2017-04-30 01:49:19
十年前有本書叫der Meere
中文叫海
好好睇 介紹左唔少古代生物
宇宙天文地理乜都有
2017-04-30 11:29:32

仲有呢個


第1隻
Diplomoceras
都係菊石目







第2隻
查唔到
2017-04-30 11:30:34
第2隻都係菊石目
但查唔到Solenoceras係邊隻菊石
2017-04-30 18:03:38
第2隻都係菊石目
但查唔到Solenoceras係邊隻菊石

https://en.wikipedia.org/wiki/Ancyloceratina
http://eol.org/pages/4784851/overview
2017-04-30 20:49:09
有無人睇po諗緊既係隻野好唔好食
利申 計劃緊開餐廳
2017-04-30 21:44:11
LM
2017-04-30 22:25:03

仲有呢個


第1隻
Diplomoceras
都係菊石目







第2隻
查唔到

生到彎位點獵槍.....
2017-04-30 22:32:30

仲有呢個


第1隻
Diplomoceras
都係菊石目







第2隻
查唔到

生到彎位點獵槍.....


While most ammonites had shells that wound tightly in a spiral,‭ ‬Diplomoceras was more unusual.‭ ‬The shells starts out straight before making a U-bend,‭ ‬then growing out back the other way before making another U-bend around.‭ ‬The shell then continues growing again until making yet another U-bend and turning back on itself,‭ ‬extending all the way back beyond the extent of the shell before the head opening appears.‭

The exact reason why Diplomoceras grew such an unusual shell is unknown.‭ ‬One reason could be so that species of Diplomoceras could recognise one another apart from the other species of ammonites that were swimming in the oceans at this time.‭ ‬A more streamlined shell may have also allowed for faster swimming similar to that of earlier orthocones,‭ ‬and may have allowed for a greater chance of predator evasion from the large shell crushing mosasaurs such as Proganthodon and Globidens that were common in the Late Cretaceous seas.‭ ‬This might also explain why Diplomoceras did not appear until the Campanian period of the late Cretaceous.

Whatever the reason why Diplomoceras grew such an unusual shell,‭ ‬the genus was clearly very successful.‭ ‬So far fossils of Diplomoceras have been found very common in Antarctica and Australia,‭ ‬but are also known from the Americas,‭ ‬Europe,‭ ‬Africa and also Japan,‭ ‬which combined with the Australian and Antarctic fossils suggest that Diplomoceras were common across most of the world‭’‬s oceans,‭ ‬until finally vanishing in the KT extinction at the end of the Cretaceous.
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