怪物追踪全集怪同学里每一篇内容的感受

自然保育社第六次讀書會心得討論報告
u時間:102年6月6日(星期四)
&&&&& 晚上17:30~21:30
u地點:生二109教室
u導讀人:劉盈昌
u成員:曾文宣、林郁庭、陳佳微、呂昱賢、王品惠、陳以臻、楊家琪、簡榕萱、楊志凱、林芝蘭、曾冠瑜、張捷
u記錄人:曾文宣
u導讀人介紹:劉盈昌(荒野保護協會講師、綠生活店長,專長:野外調查、植辨)
u讀書會進度內容:
1. 第六次課程:分類、親源演化與國際自然保育團體和國際生物貿易組織。
2. 小組成員第六次報告,應翻譯一篇文章並且額外查詢物種相關資料與生態習性,並上台以ppt檔案進行口頭分享。
3. 第六次小組成員討論,就上台報告者之內容討論發問,並且擇一深度問題至下次讀書會討論回答。
u討論記錄:
Part 1. 課程內容,講者:曾文宣
A. 為何我們要學習分類學:就像我們不喜歡被人家叫做猩猩或被戲稱從黑猩猩演化而來一樣,地球上所有的生物都是有分門別類好的,牠們有獨一無二的學名和分類地位。再者,形形色色的生物有了分類階層後才能更有系統細地區分和學習,從最大範圍的域和界,慢慢地將圈圈縮小最後成為一個物種。另一方面更能透過階層性的分類來檢視不同生物之間的親緣關係,例如我們和黑猩猩同屬靈長目,但屬於不同科。最後分類學在現今人類過度破壞大自然的情況下越顯重要,在保育上也許我們原先認為是同一物種的生物共有1000隻,在最新的研究卻發現可能為三個物種,如此一來必定有其一或期二物種的數目少於300種,這樣牠們的保育地位就變得天差地遠了!因此學習分類學必是成功達成保育的關鍵之一。
B. 現今生物的簡易分類:可分成三域五界,真細菌域、古細菌域和真核生物域,原核生物界、原生生物界、植物界、真菌界和動物界。但原生生物界的分類較為複雜凌亂,包括了許多尚無法確切分類的物種。一般認為原生生物最早由真核生物中演化而來,接著再演變出植物界、真菌界和動物界。
C. 分類階層概念:階層越往上囊括越多物種,階層越往下則包含了越少物種。而越高階層的物種之間的親緣關係越疏遠,反隻越低階層生物之間則親緣關係較為接近。
D. 地球上有多少生物:自從林奈提出以二名法命名物種以來,經歷約250年的分類學研究,人類已描述約120萬種生物。其中僅佔海洋生物的9%,陸域淡水域生物的14%。由Camilo Mora團隊最新研究利用分類階層的數量趨勢,推估地球上有870萬種(740萬種-1000萬種)生物。脊椎動物推測以命名物種已佔推估所有脊椎動物物種的3/4;而無脊椎動物(由其是節肢動物門昆蟲綱)所命名的物種不超過1/5。但可惜的是現今物種的絕種速率已大幅超越我們發現新物種的速率,因此有很多新物種在我們還沒發現前就儼然從地球消失。
E. 遙遙無期的成果:以過去20年來的動物新種發表速率推算(平均每年發表6200種新種,平均每位分類學家一生平均發表24.8種新種),需要30.3萬名分類學家,以1200年的時間才能描述完地球上所有動物新種。而總金額需耗費3640億美元。
F. 林奈的二名法:屬名(第一字母需大寫,斜體)+種小名(形容詞,斜體)。形容詞可能為分布地區或是外貌特徵,例如Polypedates megacephalus,意為大頭的泛樹蛙。而亞種或是變種則會在種小名後再加入一個形容詞。另外例如Japalura swinhonis(Gunther,1864)的意思為在1864年由Gunther科學家命名的物種。
G. 種系發生學(phylogeny):藉由DNA最新分子技術建構各生物的親緣演化關係,可以從中得知不同物種之間的親緣關係,亦可以推估某物種是甚麼時候從哪個祖先分化而來的。例如由現今的種系發生研究普遍認為雖然稱做古細菌的生物卻比起真細菌域來得與我們真核生物的親緣關係較為接近。
H. 親緣演化關係樹(phylogeny tree):像是現今對生物所做的檢索表一樣,利用各個物種的分子DNA證據來檢視之間的親緣關係,從共同祖先開始逐次往下(指隨著時間越往現今)分化成各式各樣的物種。其中分化的時間點稱為節點node,上頭開始分化的則是共同祖先存在的時間。在樹枝末梢的則是各個物種或是尚未被往下細分的生物類群,稱為taxon。若兩個taxon的生物有最近的共同祖先,則稱這兩群生物為姐妹群sister taxa。而若一「群」生物在最近的共同祖先往下只有這一群生物則稱為單系群monophyletic group;反之若在最近共同祖先往下仍有其他生物則稱為多系群polyphyletic group。分類上若是某生物類群發現不為單系群(而為多系群),則代表現今的分類方是不合宜,需要重新分門別類,最完美的樹型應是每個節點後所有生物皆為單系群的生物。
I. 註解:從演化關係樹上有時可以看到數字在橫條上,其意思代表了有多少比率其後的生物是被歸類在同一個單系群。而將分類階層套用到樹上可以發現在甚麼時間開始出現了新的分類階層,例如從節點的時間可以推估食肉目在某百萬年前分化成貓科、犬科和貂科,而又可進一步得知犬科和貂科在與貓科分家後還有一個共同祖先。
J. IUCN:國際自然保護聯盟(International Union for Conservation of Nature and Natural Resources),旨在保護大自然環境和野生動植物並且能與人類發展取得平衡解決辦法,是目前世界上最大的,最重要的世界性保護聯盟,是政府及非政府機構都能參與合作的少數幾個國際組織之一。其在1963年發布IUCN紅皮書,將現今生物的受威脅程度進行分級以利生物的永續發展。
J. IUCN red list:區分了九個受威脅級別,分別為絕種(EX,extinction)、野外滅絕(EW,extinction in the wild)、嚴重瀕危(CR,critically endangered)、瀕危(EN,endangered)、易危(VU,vulnerable)、近危(NT,near threatened)、無威脅(LC,least concern)、缺乏數據(DD,data deficient)、未評估(NE,not evaluated)。
K. CITES:華盛頓公約(Convention on International Trade in Endangered Species of Wild Fauna and Flora),於1973年6月21日在美國華盛頓簽署,總共有134個締約國。目的在建立野生物輸出及輸入國間之合作管道,以確實預防及阻止公約指定物種之非法國際貿易行為。將貿易物種分為三類列於三個附錄之中,在寵物、藥材、植栽、實驗動物等市場中是個很重要的公約。
L. CITES三附錄:附錄一的物種為若再進行國際貿易會導致滅絕的動植物,明白規定禁止其國際性的交易;附錄二的物種則為目前無滅絕危機,僅管制其國際貿易的物種,但若仍面臨貿易壓力,族群量繼續降低,則將其升級入附錄一。附錄三是各國視其國內需要,區域性管制國際貿易的物種。各附錄物種之交易皆須合法申請許可證方能進行國際貿易,但CITES只負責管控國際非法交易,無法干涉各國內的國政,因此若是針對保育保護某國本地的物種則須仰賴其他的組織與團體來進行。
Part 2. 小組成員第六次報告(譯本請見附件)
a.王郁傑,弓頭鯨的祕密武器
b.楊志凱,掠奪者怪魚
c.陳以臻,為何我們要直立行走
d.王品惠,魚嘴裡的異型生物
e.林郁庭,海兔的酷炫攻擊
f.林芝蘭,彩虹桉
g.簡榕萱,有看過羚羊帶著象鼻嗎?
h.楊家琪,好狗鼻、偉大的母親
i.張捷,殘酷二選一
j.陳佳微,有看過長獠牙的鹿嗎?、Endling-僅存者的悲哀
Part 3. 第六次小組成員討論,問題一覽
a.呂昱賢:海洋酸化的成因?
Ans. 因為工業過度排放二氧化碳,造成植物無法負荷,所以有部分二氧化碳溶於水,會與水分子結合形成碳酸。碳酸溶於水會釋出氫離子和碳酸氫根離子或進一步解離成碳酸根離子,在水中游離。若以pH值表示水中氫離子濃度,pH值下降一單位,表示水中氫離子濃度增加10倍,代表酸性增強。海水pH值在8~8.3之間,呈微鹼性。吸收二氧化碳會造成水表面pH值下降。
b.陳以臻:如何知道長江年齡?
Ans. 關於長江年齡的說法也是眾說紛紜,有人認為長江形成於距今4500萬年前,而中國學術界普遍認為長江形成於距今100萬至200萬年的更新世。過去科學家們研究長江往往從地理學、地貌學著手,研究過程中遇到一些困擾,比如地貌經過時代的變遷,沒有被完整保留下來。「我們換個思路,從地質學角度,採用比較先進和成熟的沉積物物源示蹤方法,研究長江中下游盆地沉積物的來源,從而判別長江上游的物質何時到達下游,間接指示了長江貫通東流的時限。」
鄭洪波領銜的團隊在長江中下游一帶尋找沉積物,南京六合的雨花石地層讓專家們感到興奮,「我們在位於長江沿岸的六合,發現了很多小山包被玄武岩覆蓋著,玄武岩下藏著雨花石地層。」而玄武岩可以透過放射性測年方法測出岩石的年齡。專家們從雨花石地層中篩選出名叫鋯石的小礦物,別小看了這種只有幾十微米大小的小石子,它分佈於長江流域。「我們在長達10年的實地考察、挖掘中,在長江上游段找到了和南京雨花石地層中相同的小鋯石,這就證明了若干年前這些石頭順流而下,經過幾千公里的打磨漂到了南京。」長江在此時東西貫通。六合桂子山、方山上的玄武岩距今大約2000萬年,從中推算雨花石地層的年齡,大致是2300多萬年,以此推算長江的年齡也是2300多萬年。
c.王郁傑:Corpus Cavernosum Maxillaris (文中介紹的器官)是否為弓頭鯨所獨有?
Ans. 搜尋了網路資料,此器官是前一陣子才第一次在弓頭鯨上被發現,因此其他已經做過詳細解剖學研究的鯨豚應該是沒有,但不能說只有弓頭鯨才有(可能有些尚未做過解剖學研究)。
d.楊志凱:冰淇淋頭痛的生理機制?
Ans. 冰淇淋頭痛是鼻竇毛細血管受到忽冷忽熱的影響而發生的直接原因。低溫會導致鼻竇毛細血管的收縮,而後溫度回升會使鼻竇毛細血管再次急速擴張。上顎上的疼痛感受器感知此擴張並通過一條主要的面部神經&三叉神經傳回到大腦。該神經可以感覺面部疼痛,只要大腦將神經信號識別為來自額頭的痛感即可。這與心臟病發作時導致的牽涉痛是一樣的。冰淇淋頭痛可以同時在熱或冷的外界條件下發生。。
e.曾冠瑜:各個不同氣候裙帶的生物系統為(以台灣為例)?
Ans. 【常綠闊葉林】海拔500~2000公尺的山區,氣候溫暖,溼度高,土壤肥沃,植物茂盛。主要組成是落葉樹與常綠闊葉樹,也就是亞熱帶中部終年常綠的闊葉型森林。台灣闊葉林之森林層次要比典型溫帶林複雜,充滿了各式各樣植物,昆蟲鳥類在比例上也較多,蝴蝶景觀是台灣闊葉林的重要生態特色,鳥類如白耳畫眉、深山竹雞、小鶯等。森林底層落葉堆積得厚,溼度溫度適合蕈類生長。台灣彌猴棲息於此。而不同地區的熱帶闊葉林森林的優勢樹種包括桑科、大戟科、茜草科等熱帶的類別,外觀呈現出熱帶雨林的部份特性,例如幹生花現象、兼具吸收養分與支持作用的支柱根、能增強根部固著作用的板根現象。其他森林中繁盛的天南星科植物、蕁麻科植物、蘭科植物、薑科植物與蕨類植物,包括有地生、著生與攀爬的種類,共同建構台灣熱帶林帶的景觀。
【涼溫帶山地針葉林】此區為台灣森林生態系的過渡地帶,林相為針、闊葉林混合帶,主要的樹種則為屬於檜木林的紅檜、扁柏,在氣候上此區為台灣最大降雨帶,全年雲霧籠罩,樹技上常見量的松蘿,可見此區的溼潤程度,故此區又有「霧林帶」的稱號。
【冷溫帶山地針葉林】此區林相主要由鐵杉與台灣雲杉所構成,其中又以鐵杉佔多數,因此又稱為「鐵杉林帶」。由於鐵杉與台灣雲杉生長所需的濕度不同,因此兩樹種並不夾雜生長,而是各自形成不同的林帶。鐵杉林位高海拔下位,已略與闊葉樹種相混,常見的灌木有台灣茶藨子、小葉莢迷等。棲息於區的動物種類不多,鳥類以煤山雀、火冠戴菊鳥、帝雉、金翼白眉等為主,台灣黑熊和台灣長鬃山羊也偶爾可見。
【亞寒帶高山針葉林】此區氣候寒冷,適合松柏科植物生長,這種單一樹種-冷杉構成的林相,稱之為「冷杉林帶」。這裡常見的植物為玉山箭竹,另外龍膽、圓柏和高山杜鵑也很常見。動物種類不多,大致與高山矮林地分佈的動物種類相似,較為特別的是雪山草蜥與台灣蜓蜥,為台灣特有種,不易於其他林相中見到。
【寒帶高山矮林地】由於高山受風強勁,每年約有四個月的冰雪期,因此適合生長一些耐旱耐寒的草本植物,目前約有三十餘種植物生長在高山矮林地,如玉山圓柏、玉山杜鵑、玉山籟蕭、玉山薄雪草、南湖大山柳葉菜、南湖紫雲英等,這些植物葉片上往往有絨毛或鱗毛籍以保溫,在冬季時且呈現枯乾狀態並進入休眠期以度過冷冽的冬季。原本屬於高大喬木種的玉山圓柏為適應高山氣候與環境,形成盤扎曲張的低矮權木狀,在生態學上稱「矮盤灌叢」。常見的動物有岩鷚、高山白腹鼠、華南鼬鼠與一些直翅目與雙翅目的昆蟲。
f.簡榕萱:蜘蛛蘭和螫蟹蘭的定義與差別?
Ans. 螯蟹蘭並非是蜘蛛蘭的別名,而是蜘蛛蘭這類蘭花的分類屬名。
g.林郁庭:食骨蠕蟲的生活史為何?為什麼演化上雄蟲變得這麼小呢?
Ans. 食骨蠕蟲屬中目前有發現了五種種類。,上次報告的是Osedax mucofloris。牠屬於環節動物門、多毛綱、纓鰓蟲目、西伯加蟲科、食骨蠕蟲屬。一開始食骨蠕蟲被發現時,科學家們就發現這種蟲在不同性別上的形態差異非常大。上次的翻譯有提到在鯨魚骨頭上發現的都是雌性個體,這是因為雄性的食骨蠕蟲體型都小了許多。圖上面看到的這些都是雌性的食骨蠕蟲,他們會把自己埋在骨頭裡吸食膠原和脂質,留下外面很像花的管子在漂。被嵌在骨頭裡面的這部分會有很像根的結構,裡面住著幫助牠消化的共生細菌。另外雌性的食骨蠕蟲會利用質子幫浦來產生酸液滲透骨頭,把骨頭鑽孔後就會一直住在那裡不動,靠吸食骨頭的養分生活。
另一方面,雄性的食骨蠕蟲剛好相反,牠們體型超級小但是具有移動能力,牠們不會長成成熟的成體,外觀上看起來還是和幼蟲的大小一樣,並且依附在雌性的食骨蠕蟲旁邊,住在雌性食骨蠕蟲的管子裡。一隻雌性的食骨蠕蟲可以同時容納好幾百隻的雄性食骨蠕蟲。牠們的繁殖能力非常強,雌性食骨蠕蟲可以一次排出好幾百個卵,接著在一旁的雄蟲就放出精子使卵受精,最後這些卵就會隨著海流漂到新的骨頭展開新的生活史。
最後補充一下,在牠們所排出的卵裡面並沒有發現一起共生的細菌,所以這些細菌都是後來等蟲子住在骨頭後才和牠們一起共生的。那為什麼在演化上雄性的食骨蠕蟲會變成這麼小呢?其實科學家們也還沒有很清楚,有個理論認為因為雌性的食骨蠕蟲不會動,所以雄性一旦變很小又可以住在一起的話,就能克服找不到配偶的問題。
u心得感想:撰寫人為導讀人,劉盈昌。
&&& 這學期自然保育社辦了一個讀書會:生態演化新知與生態保育近況討論及分享。讀書會的成員以翻譯外國的一些相關短文、分享並查閱補充相關資料為主。我在其中擔任導讀人的工作,並會適時的補充一些國內相關的訊息供同學們參考。一學期下來,我學到許多新知,而且同學在自然生態上的常識與知識,都有顯著的提昇。更難能可貴的是同學對生態保育問題方面的關注,大家因此都更關心臺灣這片土地上、自己生活週遭的有關的環境議題。這個讀書會,是由大四的前前任社長曾文宣同學擔任召集人,各年級的社員都人有加入。由學長帶領學弟妹學習,這是一個非常好的傳承方式。
u下一次會更好:
&&& 雖然沒有下一次的讀書會討論了,但是經過了六次的讀書會相信在施行運作上有了很多的經驗,也非常能夠了解會遇到的狀況以及該如何去解決。由衷希望接下來學弟妹若想繼續施辦讀書會,必須要好好思考如何增加讀書會成員向心力這部分,也就是要怎麼做才能讓讀書會成員真得想要透過讀書會學點甚麼,利用讀書會的機會來好好學習,而不是由於活動所逼而難產出來的報告分享,否則學習的效果是很有限的。試著在挑選讀書會成員上先下功夫,要確定小組成員是真得想要學習,並且去了解他們對於參加讀書會的動機和願景,有這番考量之下更能去協調主題和施行方式,達到真正讀書會的學習效果。生態保育上的知識是永遠不枯竭的,這些知識若沒有人去消化、去分享,就不用還倘論保護牠們了!
u其他(附件一):組員譯本
a.王郁傑,弓頭鯨的祕密武器
The bowhead whale's been keeping a strange secret - a huge organ that chills its brain, detects its food and works a lot like a penis.
弓頭鯨(bowhead whale)藏著一個怪異的秘密,它有一個巨大的器官用來冷卻腦袋、偵測食物,而且運作方式像是陰莖。
When dissecting the mouths of bowhead whales, researchers noticed something strange. Each whale had a large rod of tissue (about 12 feet long) running down the centre of its palate. Cutting into this tissue released a deluge of blood - a disproportionate amount, in fact.&
當解剖弓頭鯨的嘴巴時,研究人員發現一件怪異的事。每一隻鯨魚有很大的桿狀組織(大約長12英尺)在牠的直直延伸通過下顎中央。切斷這些組織可以釋放大量的血液(事實上是不成比例的)。
Well, turns out this organ has a similar biological set-up to a penis. Mammalian penises are made up of a spongy tissue, which increases in size and becomes rigid when filled with blood. The organ in the bowhead whale's mouth - named the Corpus Cavernosum Maxillaris - is made of similar spongy tissue.&
原來是這個器官與陰莖有相似的生物結構。哺乳類的陰莖由海綿體構成,當充滿血液時會變大變硬。在弓頭鯨嘴巴裡的這個器官,叫做(Corpus Cavernosum Maxillaris),也是由相似的組織組成!
The first clue of this organ's purpose came from its surprising heat. Though the whales had died hours earlier, this organ was much warmer (sometimes as much as 12 degrees warmer). By pumping hot blood into this organ and opening its mouth, a bowhead whale can keep cool and draw heat away from its brain. It sounds strange to talk of the whale overheating, considering it lives in the Arctic ocean, but their round shape and huge amounts of blubber make this a real danger.
第一個有關這個器官功能的線索是它令人驚訝的熱度。雖然鯨已經在幾個小時前死亡,這個器官比其他部分溫暖許多(通常會比其他部分高出12度)藉由壓縮高溫的血液進入這個器官並張開牠的嘴,弓頭鯨可以保持涼爽並且將腦的熱量帶走。「鯨魚過熱」這件事情聽起來有點怪異,特別當我們想到牠們是住在北極的海洋時,但是他們的球狀的身形以及大量的脂肪組織(blubber)使它成為真實的危險。
But the Corpus Cavernosum Maxillaris has a second job - plankton detection. Bowheads feed by opening their mouths and swimming forward, a strategy requiring a lot of energy. This pays off if it catches a lot of plankton, but is very costly if it doesn't. As the new organ is packed with touch-sensitive nerves, it looks like its second function is to tell the whale whether it should stay feeding or cut its losses and shut its mouth.
但是Corpus Cavernosum Maxillaris有另外一項工作:偵測浮游生物。弓頭鯨藉由張開牠的大嘴並向前游動來捕食,這項策略必須消耗大量的能量。! 如果沒辦法,那代價是非常昂貴的!這個新的器官包含了許多感覺神經,似乎它的第二功能是告訴鯨魚現在是否應該繼續捕食,或是關上嘴巴以減少能量損失。
Source & Reference
下頷的桿狀組織:
b.楊志凱,掠奪者怪魚
Say hello to the sarcastic fringehead, a fish often suggested as &the inspiration for the Predator&.
跟這隻掠奪者怪魚說聲嗨!這種與通常被視之為「外星人的靈感」。
With its mouth closed, the sarcastic fringehead (Neoclinus blanchardi) doesn't look like anything particularly special. It's about a foot (30 cm) long, a mottled brown colour and makes its home inside objects such as mollusc shells or litter, where it positions itself so that only its head is visible. But if something should stray too close it darts out and opens its cavernous maw. If this isn't enough, it starts biting with its needle-like teeth.
當他的嘴巴閉上時,掠奪者怪魚看起來並不特別。他大約有30公分長,帶有棕色的斑點,以軟體動物的殼或枯枝落葉為家,並調整到只有他的頭會被看到的位置。但若有東西誤入他的範圍,他會衝出並打開他海綿體狀的咽喉。若這樣的威脅還不夠,他會開始用針狀的牙齒撕咬。
Being highly aggressive and quite solitary creatures, they don't take kindly to other sarcastic fringeheads invading their territory. If two are too close they display their huge mouths, sometimes making warning bites toward their competitor. If this doesn't solve the dispute (and it probably won't - they have quite poor eyesight), they mouth-wrestle. By forcing their mouths together they can find out who is the bigger fish.
身為一種具有侵略性且有一點孤僻的生物,他們對其他侵略他們領地的掠奪者怪魚並不友善。若兩隻掠奪者怪魚太過靠近,他們會打開他們的大嘴,有時會咬向他們的競爭者作為警告。若是這樣還不能解決紛爭(這通常不太有用,因為他們的視力很差),他們會以嘴巴搏鬥,藉此可以得知誰是比較大的魚。
If you're wondering where the name comes from, it's from the appendages above their eyes. Oh, and the sarcastic part refers to their aggression rather than any cruel wit. &Sarcastic& and &sarcasm& both have their root in the Greek word &&&&&&&?& (sarkasmos), meaning &to tear or rend flesh&.
若你在想他們的名字的由來,這是由於他們眼睛上方的附屬器官。哦,挖苦的部份使指他們的侵略性而不是他們殘忍的機智。&Sarcastic& and &sarcasm&都源自於希臘字&&&&&&&?& (sarkasmos),指的是撕裂或撕開肉體。
Source & Reference
掠奪者角力影片:
c.陳以臻,為何我們要直立行走
Why do we walk upright? In essence, it&s a very basic question. But the answer is more complex than you might think&
為什麼我們是直立的行走著?在本質上,這是非常基本的問題,但答案卻是複雜得超乎你的想像...
The movement of early humans from an arboreal ifestyle to a terrestrial one seems logical. One hypothesis suggests that hominins were forced to move out of the trees because of climate change, which eroded the tree cover. However, recent research done at the University of York challenges this rather traditional view.
早先的人類從樹木生活方式到陸地行動看起來是合理的。有個假設認為人類被迫離開樹木是因為氣候的改變,進而導致樹木的遮蔽處受到侵蝕。然而,約克大學最新的研究挑戰了這個傳統的觀點。
There are many good reasons to come down to earth. There are more opportunities to trap or hunt for prey. Rocky outcrops also gave better shelter and protection. The researchers say that the terrain in which the hominin found itself was steep and rugged. Bipedal motion allowed early man to effectively occupy this niche.
有許多好的理由讓人類來到地面上生活。設陷阱、打獵、補食的機會更多了。岩石凸出處也可做為更好的遮蔽跟保護。研究者指出早先的人類是生活在陡峭、崎嶇不平的陸地上。兩足行動使得早期人類可以有效率的從事之。
Bipedalism also had other benefits. It left the upper limbs free, which in turn led to increased manual dexterity and the development of tools. Furthermore, in response to the varied terrain into which they had moved, hominins developed better locomotor skills that enabled them to cover the uneven ground with ease. The terrain may also account for the development of advanced cognitive skills, such as navigation and communication.
兩足運動也有其他好處。它讓上肢得以解放,增加手的靈巧度及工具的發展。此外,導因於他們必須在各個不同的地形上移動,人類發展了可移動的能力得以在不平坦的地面上輕鬆的行走著。陸地也同樣的促成更佳的認知能力發展,像是導航及溝通。
&Our hypothesis offers a new, viable alternative to traditional vegetation or climate change hypotheses. It explains all the key processes in hominin evolution and offers a more convincing scenario than traditional hypotheses.&, said one of the researchers, Dr Isabelle Winder.
「我們的假設提供了除了傳統植物或氣候假設之外的新及可行的選擇。它解釋了在人類演化上所有關鍵的進程並且提供比起傳統假設更具有說服力的方案。」參與此研究的Isabelle Winder博士如是說到。
Source & Reference
d.王品惠,魚嘴裡的異型生物
Cat got your tongue, or is it Cymothoa exigua?
為何說不出話來了?又或者是因為縮頭魚蝨?
Parasites often alter their host's behaviour or appearance, but Cymothoa exigua goes one further - it is the only parasite known to replace an entire organ. Its unfortunate host is typically the rose spotted snapper, which it enters through the gills and lodges itself at the back of the mouth. It hooks its claws at the base of the tongue and interrupts the blood flow, consuming it instead. Due to the lack of blood the tongue atrophies and falls off, where the isopod parasite attaches itself to the remaining stub. It then &becomes& a functional tongue for the fish, able to be moved as the fish would have moved its original tongue.
寄生蟲經常改變牠們宿主的行為或外觀,但是縮頭魚虱會更進一步-他是所知唯一會替換整個器官的寄生蟲。這個不幸的宿主通常是玫瑰斑笛鯛,縮頭魚虱會經由魚鰓寄宿在牠的嘴巴後面,並且用爪子勾住魚舌的底部並中斷血管的流動並去吸食它。由於缺乏血液,舌頭會逐漸萎縮、脫落,接著縮頭蟲虱(等足類寄生蟲)會將自己貼在舌根的位置並且成為了魚「具有功能性的新舌頭」,當魚移動牠的「舌頭」時,縮頭魚虱就能夠移動。
Like most cymothoid isopods, C. exigua is a hermaphrodite. In one study females were only found in the mouth, whereas males could be found in the gills and the mouth (and in the mouth they were clinging to females, suggesting copulation). A small proportion of extremely unlucky fish were found with females as the tongue and males simultaneously occupying the gills. Despite the &organ-replacement& part, it doesn't appear C. exigua has other adverse effects on the fish.&
就像大多數的等足類動物一樣,縮頭魚虱是雌雄同體。在一項研究指出雌性只在魚嘴被發現,然而雄性可在魚的鰓和嘴裡找到(而且在嘴裡雄性會緊臨雌性來暗示交配)。有極小部分不幸的魚被發現嘴裡有雌性縮頭魚虱然而魚鰓也同時存在著雄性魚虱。盡管成為了器官的替代部分,縮頭魚虱似乎對魚沒有什麼負面的作用。
In case you were wondering (and we're sure it crossed your mind at some point), C. exigua does not affect humans. That said, don't pick one up - they deliver quite a nip.
假如你想知道(而且我們不確定你是否在某種程度上被牠嚇到了),但縮頭魚虱並不會影響人類。或者這樣說,還是不要抓牠們你有可能會被咬上一口。
Source & Reference
原始論文:
食魚舌寄生縮頭魚蝨簡介影片:
不同類型的雌雄同體介紹:
可愛生活史動畫影片:
e.林郁庭,海兔的酷炫攻擊
Just before a lobster can turn a sea hare into dinner, the hare squirts unpalatable purple ink and opaline into its would-be attacker's face. New research shows that this opaline deters lobsters by blocking its sense of smell.
正當有隻龍蝦要把海兔當成晚餐時,海兔往攻擊者的臉噴出難吃的紫色墨水和乳白色的物質。一項新的研究顯示這種乳白色的物質(opaline)可以藉由阻礙龍蝦的嗅覺以震懾住他。
For any hungry lobster, the soft slow-moving sea hare (genus Aplysia) looks like an excellent meal. But the sea hare has two chemical defenses: purple ink and a sticky white substance known as opaline. These chemicals (stored in separate glands and able to be squirted independently) form a last a line of defense for the sea hare. But how does opaline deter attackers?
對一隻飢餓的龍蝦來說,一個又軟、移動又慢的海兔(海兔屬)看起來就像美味的一餐。但是海兔有兩種化學防禦機制:紫色墨水和被稱作opaline的白色黏性物質。這些化學物質(儲存在不同的腺體中也可以分別獨立噴出)形成了海兔的最後一道防線,但是opaline是怎麼震懾住攻擊者的呢?
To find out, researchers from Georgia State University (Atlanta, US) painted the antennules (the first pair of antennae and olfactory organs) of spiny lobsters with opaline mixtures. Each lobsters' chemosensory neuron activity was measured when it was presented with &shrimp juice& - water shredded shrimp had been immersed in for half an hour.
為了找到答案,美國亞特蘭大喬治亞州立大學的科學家在多刺的龍蝦觸角上(觸鬚的第一對和嗅覺器官)塗了opaline的混合物,然後把蝦子汁(切碎的蝦肉泡在水中半小時)放進水族箱中,並同時測量每一隻龍蝦的化學感受神經活性。
Each mixture yielded a different result. The neurons of lobsters painted with water-soluble but sticky opaline (deprived of the usual amino acids it contains) were greatly inhibited, whereas lobsters painted with the amino acids of opaline (but not in a sticky substance) reacted to the shrimp juice normally. Lobsters painted with carboxymethylcellulose (a substance that mimics opaline's stickiness) also couldn't detect the shrimp juice.
每一個混合物都產生了不同的結果。塗了水溶性但還是黏黏的opaline (去除掉所含的胺基酸)的龍蝦神經活性被大大的抑制,然而塗了含有原本胺基酸的opaline (不再黏黏的)的龍蝦神經會對蝦子汁做出正常反應。
The results indicate rather than overpowering the lobster's sense of smell, opaline's stickiness &inactivates& it. While the lobster tries to rid itself of the substance and restore its sense of smell the sea hare makes its escape. The team say it is the first experimental demonstration of sensory inactivation as a defense against predators.
結果顯示opaline並不是難聞的讓龍蝦無法忍受,而是opaline的黏性會讓龍蝦的嗅覺失去活性。當龍蝦試圖擺脫opaline好使得嗅覺恢復時,海兔就可以逃跑。研究團隊說這是第一次實驗上示範將掠食者的感官抑制以當作防禦。
Source & Reference
潮間帶的化學特戰隊:
海兔遭受攻擊噴紫色墨水與黏性物質影片:
黏性物質的化性:
f.林芝蘭,彩虹桉
The most colorful tree in the world: The Rainbow Eucalyptus tree (Eucalyptus deglupta).
世界上最豐富多彩的樹:彩虹桉樹(尤加利)(桉樹deglupta)。
The Rainbow Eucalyptus (Eucalyptus deglupta) or 'MINDANAO GUM' looks almost like it's been spray painted, but the up to 70-m tall tree is colored this way completely naturally. Its bark can take on a yellow, green, orange and even purple shading.
彩虹桉樹或&棉蘭老島口香糖&看起來幾乎像它被噴上了多色的漆,但高達70米的高大喬木以彩色呈現方式是完全自然發生的。它的樹皮上可呈現黃色,綠色,橙色甚至紫色陰影。
If you want to spot a Rainbow Eucalyptus tree live and in all its glory, you&ll have to travel to Indonesia, Papua New Guinea or Philippines where the tree grows natively. However, it has been introduced worldwide as an exotic wood in South America, Malaysia, Sri Lanka, China and other countries.
如果你想發現一個彩虹桉樹現場,你必須前往印度尼西亞、巴布亞新幾內亞或者菲律賓,在這些地方,是彩虹桉樹自然生長的起源地。但是,在南美洲,馬來西亞,斯里蘭卡,中國和其他國家,它已經被推廣到世界各地當作富有異國情調的木材。
Source & Reference
彩虹桉在台北:
g.簡榕萱,有看過羚羊帶著象鼻嗎?
The distorted-looking nose of the Saiga antelope (Saigatatarica) is probably its most distinctive feature, and it's thanks to this bulbous snout that Saigas can live in the dry plains and semi-deserts of Central Asian countries. In warm summers the nose filters the dusty air and in the cold winters it warms the air before it's breathed in. Saigas reach about 1-1.5 metres long and 0.8 at the shoulder, about the size of sheep.
賽加羚羊這個扭曲外貌的鼻子或許是他最明顯的特色,他得感謝這個球莖狀的口鼻讓他可以住在乾燥平原和半沙漠中亞國家。可以在溫暖的夏天過濾空氣中的塵土,在寒冷的冬天讓空氣變溫在吸入體內。
When breeding seasons comes around, each Saiga male will attempt to create himself a harem of around 5-10 females. Intense fights (sometimes to the death) are fought for harems. Males devote their energy to protecting their harems, even at the expense of grazing, and as a result male mortality rates can reach over 90% simply due to exhaustion.
來到繁殖季節時,每隻賽加羚羊會傾向建立屬於自己的後宮,約5~10雌性。他們會為此打鬥(甚至死亡)雄性會貢獻他們的力氣去保衛他們的後宮,即使有百分之九十的比例因為疲累過度而導致死亡。
The Saiga is the only surviving member of its genus, and it's critically endangered today. Until the 1990s the total Saiga population was strong, reaching around a million individuals, but when the Soviet Union collapsed poaching became rife. The loss of large numbers of males, hunted for their horns (which are desired for - you guessed it - traditional Asian medicine), created a massive drop in birth rates and prevented the population recovering. Hopefully the programs which are in place today will allow Saiga populations to recover.
賽加羚羊是其屬的唯一倖存的成員,然而它們卻瀕臨滅絕。直到20世紀90年代塞加總人口是多量的,達到約一百萬隻,但是當蘇聯解散後偷獵蔚然成風。大量的雄性被獵殺因為他們的牛角(這些牛角被大量需要 - 你猜對了 - 亞洲傳統醫藥),創造了出生率大量下降和阻礙羊族數量恢復困難。希望有計畫能夠恢復賽加羚羊的數量。
Source & Reference
h.楊家琪,好狗鼻
Though we often think of natural selection when we talk about evolution, there is also artificial selection: humans decide which plants and animals reproduce, depending on what characteristics humans find desirable.
雖然我們通常認為,當我們談論進化論的自然選擇,也有人工選擇:人類決定植物和動物的繁殖,這取決於人類找到什麼稱心的特點。
The bloodhound is an excellent example of artificial selection. This breed of dog is one of the oldest scent hounds in the world. Its lineage can be traced back in Europe to before the time of the Crusades. Most believe the breed originated in Constantinople. The name &bloodhound& does not refer to the dog following a trail of blood. Instead, it refers to the fact that this hound's lineage was tightly controlled to produce an animal whose nose is so reliable, the evidence it finds stands in a court of law.
獵犬是人工選擇的一個很好的例子,這個品種的狗是在世界上最古老的嗅覺獵犬之一。在歐洲,牠的血統可以追溯到十字軍東征前,大多數人認為該品種起源於君士坦丁堡。&獵犬&的名字並非指會循著血跡的狗。相反,它事實上是指,這種血統的獵犬會因為其鼻子非常可靠,而被嚴格地控制生產。牠所發現的證據會被法庭所採納。
So how does the bloodhound track? The bloodhound has enlarged, sensitive scent membranes in its nose, containing 230 million olfactory cells (40x more than humans). It can distinguish smells at least a thousand times better than humans. The bloodhound's wrinkly face and long ears help trap and sweep up scents. It has poweful shoulders, which help it keep close to the ground and on a trail.........sometimes as far as 130 miles.
那麼,獵犬如何追蹤?獵犬在其鼻子有擴大,且敏感的氣味皮膜,含有2.3億個嗅覺細胞(是人類的40倍以上)。牠分辨氣味的能力至少是人的1000倍。獵犬充滿皺紋的臉與長耳朵有助於捕捉與蒐集氣味。牠強而有力的肩膀,幫助牠與地面保持接近且保持追蹤&&有時可以到達130英厘遠。
The nose is not the only characteristic that humans bred this dog for. The dog was also bred to have a desire to work. A dog with a good nose is useless to a human if the dog doesn't want to cooperate.
牠的鼻子並非人類唯一想繁殖此品種狗的特點。這種狗狗也擁有工作的意願。如果狗狗不配合,那即使擁有優秀的鼻子對人類來說也是沒用的。
Source & Reference
i.楊家琪,偉大的母親
Happy Mother&s Day everybody! (Really, though, we don&t need a special day to appreciate our mothers&)
母親節快樂!(不過說真的,我們不需要這樣特殊的日子才來表達對母親的感謝)
The Giant Pacific Octopus makes the ultimate sacrifice for her children. They only breed once in their lives. After mating, the female Giant Pacific Octopus searches for a den in which she must lay her fertilized eggs. She is very picky and makes sure that it is as secure as possible. She lays up to 100,000 eggs, which hang in bunches from the sides of the den. These nutrient-rich eggs can be easy food for any sea creature.
北太平洋巨型章魚為她的孩子們做了最大的犧牲。他們一生僅有一次繁殖。在交配後,雌性北太平洋巨型章魚會搜尋洞穴以產出受精卵。她十分地謹慎挑剔,確保該地是盡可能的安全。她一次會產出高達十萬顆以上的卵,成串的掛在巢穴的邊緣。這些富營養的卵十分容易成為海中生物們的食物。
So she protects them. For the next six months, the mother doesn't leave the den, not even to eat. While she stays there, she gently strokes the eggs to keep them clean and algae-free. Eventually, the ordeal takes a toll on her, and she dies. Her eggs eventually hatch into tiny, albeit fully developed baby octopi.
因此她保護他們。在接下來的六個月中,章魚媽媽在巢穴寸步不離,甚至未進食。當她在巢穴中,她會溫和的撫摸卵以保持清潔、使不生苔藻。最終,此磨難使她付出生命的代價。她的卵終於孵育成小小的、發育良好的小章魚寶寶。
This behaviour is anomalous. Such acts of mothering are normally associated with social animals like mammals and birds. Usually, adult Giant Pacific Octopi are solitary and aggressive to one another. It is therefore, truly interesting that they display such maternal instinct.
這樣的行為是不正常的。像這種母愛的展現,通常與社會性動物,如哺乳類、鳥類相關聯。但通常,北太平洋巨型章魚是獨居且對同伴有攻擊性的。因為如此,他們會展現這樣的母性才顯得特別有趣。
So let your mother know you love her!
所以,讓你媽知道你超愛她的吧!
Source & Reference
北太平洋巨型章魚簡介:
護幼行為影片:
j.張捷,殘酷二選一
Many of us are familiar with the unique mating rituals of birds. Birds of paradise, in particular, are famous for their strange and elaborate dances. Generally, a male performs a dance or has a display ready to woo a female. One male, one ritual, one female. But the blue-backed manakin (Chiroxiphia pareola) had to one up everyone.
相信大家對於鳥類擁有獨特的交配儀式並不陌生。其中最常被提及的就是天堂鳥那奇異又精緻的舞蹈。一般而言是由雄鳥跳舞或展示牠們已經做好追求異性的準備,通常是一個雄鳥用一種儀式,吸引單一雌性。但在藍背嬌鶲&(Chiroxiphia pareola) 就不是這麼一回事,追求者不但要會跳舞,還要成為舞王。
The blue-backed manakin can be found in the tropics of South America. It's a small bird, about 13cm long, but the male's black body and face, blue &cape& on its back, and red toupee, make it stand out. The female is mostly olive green. What makes this bird stand out from others is the way the male attracts a female: two males coordinate a dance to attract a female, which mates with only one of the males.
藍背膠鶲是一種生存于南美洲的小型鳥類,成鳥大約13公分長。雄雌鳥體色差異大,其中雄鳥具有黑色的面頰與軀幹,藍色的披肩與紅色的頂髮讓牠們鮮艷出眾;而雌鳥身體大部分是橄欖綠色。而牠們最獨樹一格的就是雄鳥吸引雌鳥的方式:由兩隻雄鳥交織一段舞蹈來吸引雌性,而雌鳥再從中擇一作為伴侶。
The males choose a branch (usually the same one, year after year), on which to dance. One male will jump into the air, while the other male scoots forward on the branch. When the first male lands on the branch, the second male jumps into the air, and they reverse roles. This creates a &cartwheel& type dance. When a female lands on their branch, the males dance facing her. If she chooses to mate, only the dominant male will mate with her. The other male will not mate until the dominant male dies and the lone male partners with another male and becomes the dominant male.
這樣的&一對&雄性會選擇一個固定的枝條作為他們年度舞蹈比賽的擂台。當其中一隻雄鳥踏上枝條,另一隻雄鳥隨即振翅高飛,然後兩隻輪流起舞,創造一種&車輪戰&似的舞蹈形式。當雌鳥踏在該枝條上時,這對雄鳥就會面對的著雌鳥繼續跳舞,而雌鳥就會選擇其一作為交配對象。剩下的那隻可憐單身漢在牠的舞伴死去之前都沒有辦法獲得交配的機會,除非牠選擇換個舞伴並成為兩者中比較受青睞的那一位。
Only 6% of bird species use a lek mating system (in which males gather to display for females). Blue-backed manakins are even more unusual because the males don't just display near each other, they actually display together.
僅6%的鳥類採取這種群體的求偶模式。藍背嬌鶲的求偶儀式更是不尋常,雄鳥們不僅是一起跳舞,而且牠們的舞蹈還必須由兩者一同進行。
What does the submissive male gain from this arrangement? He doesn't get to mate, although he's working hard to display to females. Researchers are intrigued by the lek mating system, and there is a great deal of research into the advantages of the system.
那相對弱勢的那一方從這樣的行為模式中獲得了什麼呢?儘管一樣很賣力跳舞,卻沒有得到交配機會。學者們對於這種群體求偶系統這樣的安排在演化上有沒有什麼優勢仍然沒有一個好的解釋。
Source & Reference
親屬選擇(Kin selection)在嬌鶲類的原始論文:
求偶行為原始論文:
群體求偶行為影片:
嬌鶲屬像麥可傑克森月步的求偶影片:
k.陳佳微,有看過長獠牙的鹿嗎?
When you think of male deer fighting over females, you probably think of clashing antlers. After all, this is the way the majority of deer species do it. But water deer, or Hydropotesinermis (meaning &unarmed water-drinker) do things a little differently: when two males want to compete for territory, they stand together and swing their heads down to wound each other's neck and shoulders with their long canines. These fights can cause fairly serious wounds. When one male is defeated he lays his head on the ground, whereupon the victor stops the fight and chases the loser out of his territory.&
當提到一隻公鹿為了一隻母鹿而和其他公鹿競爭時,你可能會認為他們會用鹿角衝撞彼此。畢竟,這是大多數的鹿科動物會有的競爭行為。但對獐(學名的意思是沒有武裝的喝水者)而言競爭的方法又有些不同,當兩隻公獐要競爭地盤時,他們會對站然後擺動頭部用犬齒來攻擊傷害對方的脖子和肩膀,這種攻擊會造成很嚴重的傷害。當一隻公獐被打敗時他會把他的頭攤在地上,於是贏家會停止戰鬥並驅逐輸者離開他的領土。
The water deer's features make it a very unusual member of the Cervidae family, with only muntjacs possessing similar teeth (though they have small antlers too). It also shares its strange appearance with musk deer (which belong to the family Moschidae), who also have tusks rather than antlers.
獐的這個特徵使他成為鹿科動物中很特別的一物種,唯有山羌擁有和獐相似的牙齒而已(雖然他們也有小獠牙)。這個奇怪的特徵和香獐(麝科),他們也是有獠牙而不是角。
There are two subs the Chinese water deer (Hydropotesinermisinermis) and the Korean water deer (Hydropotesinermisargyropus). Importing and escapes have created a sizeable population of Chinese water deer in Britain. Water deer are relatively small in size, reaching a height of just over 65cm at the shoulder.&
一共有兩個獐亞種,有中國獐(Hydropotesinermisinermis)和韓國獐(Hydropotesinermisargyropus)。進口和逃逸的情形已經在英國形成了數量蠻龐大的中國獐族群。獐是體型較小的鹿,肩膀的高度大概就65公分高。
Source & Reference
獠牙照與頭顱照:
l.陳佳微, Endling-僅存者的悲哀
&Endling& might just be the loneliest term in the English language. An endling is the last member of a species or subspecies, and when this lone individual dies its species is extinct.
&Endling&僅存者可能是英文字裡最孤單的一個詞了。僅存者顧名思義便是一個物種或亞種的最後一個成員,而且一旦這唯一的個體死後這物種就滅絕了。
Several endlings have been recorded in recent times. Martha, the last passenger pigeon, died in 1914 in Cincinnatti Zoo, and she was frozen in a block of ice and sent to the Smithsonian Institution, where she sits (in a cupboard) today.She was the last of a species that had numbered several billion before Europeans arrived in&North America. Human actions are a oft-repeated theme in the story of endlings.
近期有記錄到一些&Endling&僅存者,最後一隻旅鴿瑪莎在1914年死於辛辛那提動物園並且她被凍結在一塊冰裡然後被送給史密森學會存放至今,。他是最後一隻許久前曾在歐洲人到達北美前以數十億隻的數量生存在世上的物種。人類經常在僅存者的故事裡能看到我們經常重複的主題-滅種。
The animal in the photo is Benjamin, the last thylacine (or Tasmanian Tiger). Benjamin - who may have actually been female - lived out his days in Hobart Zoo. On the 7th of September, 1936, Benjamin died due to neglect. Other species endlings have included the last quagga and the Caspian tiger, though there are certainly more we don't know of.&
照片裡的動物是班傑明,最後一隻袋狼(塔斯馬尼亞虎)。最後的日子在賀巴特動物園度過的班傑明現在被科學家認為可能是母的,在1936年9月7日班傑明因為沒受到重視而死了。其他&Endling&僅存種還包括最後的斑驢和裏海虎,雖然當然還有許多我們不知道的&Endling&僅存者存在。
Perhaps the most well-known recent endling is the Pinta Island giant tortoise Lonesome George, who died on 24th June last year. George's status as anendling may
DNA from 17 hybrid tortoises indicates that they have some genetic material from George's subspecies. Given tortoises' long lifespans, the researchers have hope that the hybrids' parents may still be alive somewhere on the Gal&pagos islands. Unless these purebred specimens are found (if they are still alive), Lonesome George holds a special place as our most famous and recent
或許最有名的&Endling&僅存者是寂寞喬治,最後一隻平塔島象龜,死於去年6月24日。喬治身為&Endling&僅存者的身分可能要被撤銷,從17個混種陸龜身上的DNA顯示他們有一些基因是來自像喬治一樣的平塔島象龜。基於陸龜都很長壽,科學家希望這些混血陸龜的父母依舊存活在加拉巴哥群島。除非這些純種的樣本被發現(如果還存活的話),寂寞的喬治現在仍然會保持在我們心中最有名也最特別的地位。
Source & Reference
最後一隻塔斯馬尼亞袋狼的生前紀錄影片:
倖存者衝擊:
寂寞喬治到底寂不寂寞:
積極搶救倖存者物種的紀錄片(國家地理雜誌【搶救瀕危動物】2012):
自然保育社第五次讀書會心得討論報告
u時間:102年5月31日(星期五)
&&&&& 晚上17:30~21:30
u地點:生科二館109教室
u導讀人:張捷
u成員:曾文宣、林郁庭、陳佳微、呂昱賢、王品惠、楊志凱、林芝蘭、張捷
u記錄人:曾文宣
u導讀人介紹:張捷(清大自保社19屆課程長,專長:演化、植辨)
u讀書會進度內容:
1. 第四次讀書會課程:爬蟲類概論
2. 小組成員第五次報告,應翻譯一篇文章並且額外查詢物種相關資料與生態習性,並上台以ppt檔案進行口頭分享。
3. 第五次小組成員討論,就上台報告者之內容討論發問,並且擇一深度問題至下次讀書會討論回答。
u討論記錄:
Part 1. 課程內容,講者:曾文宣
a.何謂爬蟲類:牠們是一群分布廣泛的外溫動物,但是在能量的利用方式各出奇招,巧妙地很成功適應除了南極洲以外的各個環境。比起同樣歷史悠久的兩棲類,爬蟲類的登陸是這類生物最引以為傲的所在。牠們全身批著鱗片以減少水分的散失,並且發展出羊膜蛋來減緩胚胎在陸上可能遭遇到的碰撞及危險。而現存的爬蟲類群有龜鱉類、鱷類、有鱗類(蛇和蜥蜴)以及活化石喙頭蜥類。
b.演化歷史:
c.:爬蟲類皆行有性生殖且為體內受精,部分物種的生產方式為胎生。而在爬蟲類中所謂孤雌生殖的例子更是比起其他脊椎動物多見,亦即不需要雄性個體亦能產下後代。
d.體溫調節:由於爬蟲類是外溫動物,所以在新陳代謝上不需要消耗能量來保持體溫(這是鳥和哺乳動物耗掉最多能量的地方)。所以爬蟲類動物可以長時間內只吃一餐,到了冬天多數物種會展現冬眠的行為,在這期間這些生物的新陳代謝率極低,每分鐘心跳可能只有4下。
e.進食習慣:許多爬蟲類非常挑食,牠門有專一性的菜單。例如加拉巴哥的海鬣蜥只以岩上的海藻為食、非洲食卵蛇只吃蛋、台灣的鈍頭蛇只吃蛞蝓和蝸牛、眼鏡王蛇只吃其他蛇類、革龜只吃水母等。這意味著在演化這些生物已經高度特化成為了適應獵物而精心打造的生存方式和外型構造,像是鈍頭蛇的右排齒型符合蝸牛的右旋殼型。
f.特殊感官:蛇類和蜥蜴對於味覺和嗅覺十分敏感,牠們會不斷吐舌頭來偵測空氣中的氣味分子,並且傳到口腔上方的傑克森氏器官(梨鼻器)分辨氣味以及濃度。有些蛇類,例如蟒蛇和蝮蛇,在鼻孔後方有個洞稱為感熱頰窩,這個器官可以感應到生物體發出的紅外線,因此在黑暗之中也可以追蹤獵物。
g.防禦機制:爬蟲動物大多具有極佳的保護色,可以隱藏在環境之中不被發現。有些品種的蛇類在遭遇危險時會裝死並且發臭來使掠食者興趣缺缺,而有大約1/5的蛇種具有珍貴的毒液可以在緊急狀況下保護自己。在蛇類當中亦有不少物種展現厲害的貝氏擬態,例如無毒的牛奶蛇模仿劇毒的珊瑚蛇。另外特殊的防衛機制像是澳洲傘蜥的頸部皮摺以及澳洲的多刺魔蜥在遭遇危險時會從眼睛噴出血液來嚇跑敵人。
h.岌岌可危:科學家們在三月時發布藉由評估隨機抽出的1500種爬蟲類保育現況,估計全球爬蟲類已知的9084種約有19%受到滅絕的壓力。其中有12%歸類於極危(Critically Endangered),41%歸類於瀕危(Endangered),47%歸類於易危(Vulnerable)。主要的元凶當然是人類,除了棲地的破壞與過度開發影響甚劇外,蛇皮、鱷魚皮、龜板等動物性製品更是加重了物種滅絕的命運。另外對於爬蟲類的誤解也是因素之一。
i.真相與誤解:事實上大多爬蟲類性情溫馴,許多人以為蛇類有毒或是會主動攻擊人這些都是錯的。通常這些生物把人類視為可怕的存在,牠們通常會靜止不動等待我們離去,被發現後第一時刻落跑,除非被抓住否則牠們很少咬人。在你我身邊,因車禍和被蜜蜂叮咬造成的死亡人數是遭蛇吻致死人數的10倍之多。而現今醫學的發達使致死率更加下降,每年在美國被毒蛇咬的8000多人中,只有5到10人身亡。
&&& Part 2小組成員第五次報告(譯本請見附件)
a.楊志凱,吃冰讓你頭痛了嗎?
b.呂昱賢,餐桌上的海洋生態浩劫
c.王品惠,進擊的蟲草!
d.林郁庭,鯨魚死掉之後、吃骨頭的鼻涕花
e.林芝蘭,歐卡歐卡鯊人鯨
f.張捷,鐵球知多少?、非先天決定一切!
g.陳佳微,早期鳥類是否以四個翅膀飛行?
Part 3第五次小組成員討論,問題一覽
a.呂昱賢:上次報告中,從影片中看到蠑螈也會以蜷曲起身體滾動的行為,但為何是用腹部朝外的方式滾動?
Ans. 此種蠑螈名為Mount Lyell salamander,分布於北美的溫帶森林,淡水溫泉,岩石區,和洞穴。但是相較於我們提出的問題,在下面連結中的影片有稍為描述到,他是以腹部著外的方式滾動,所以可能是我們看錯。
b.王品惠:黑頭海蛇與青環海蛇地理分布的比較
Ans. 黑頭海蛇分布在熱帶及亞熱帶,南中國海附近,包括越南、中國廣東至浙江與及台灣海岸;澳洲及新幾內亞一帶的海域,澳洲北領地及西澳州沿岸;日本西南群島及沖繩島,有時也會順著對馬海流游至北海道。
青環海蛇則廣泛出沒於印度洋海域,包括波斯灣、伊朗、巴基斯坦、印度、斯里蘭卡、孟加拉國、緬甸、泰國、馬來西亞、菲律賓群島、韓國、日本、索羅門群島、南中國海(包括海南島)、東中國海(包括台灣)、中國山東及遼東沿岸、新幾內亞、澳洲等海域。
c.林芝蘭:長鰭領航鯨為什麼是海豚科?
Ans.鯨豚目(Cetacea)下可以分成齒鯨和鬚鯨,而海豚算是跟齒鯨比較相近的類群,所以在談論海豚、齒鯨跟鬚鯨時,會以前兩者一起討論。但齒鯨和鬚鯨算是俗稱,沒有一個很嚴整地分類依據。而長鰭領航鯨確定也是海豚科的成員(Delphinidae),齒鯨跟海豚這類另有細分成鼠海豚科、海豚科、江豚科、抹香鯨科、一角鯨科、喙鯨科...等。令人驚訝的是虎鯨也是海豚科。
d.陳佳微:哪些物種是列於近年最具代表性的復種動物名單之中?
Ans. Woolly Mammoth猛獁象,3,000到10,000年前絕種,復種最具代表性生物,其基因保存較為完整,但絕種時間距今甚久。
Gastric-Brooding Frog胃育蛙,分別有兩個不同物種的胃育蛙,南方胃育蛙(Rheobatrachussilus)和北方胃育蛙(Rheobatrachusvitellinus),兩個分別在 1973和1984被發現,但在1980年代中雙雙消失。
Passenger Pigeon旅鴿,十九世紀曾經以數十億隻數量飛行於北美洲的天空,然而在二十世紀歐洲人移入因被大量獵殺而滅絕。基因學家Ben Novak指出她可以從在博物館保存的旅鴿樣本中任意組織取出具有一半以上完整基因的細胞,而目前已有許多科學家投入旅鴿的復種行列。
Dodo渡渡鳥,渡渡鳥被認為在1662曾大量生活在澳洲大陸,幾百年後被荷蘭船員發現。渡渡鳥被發現後開始被外國船員獵殺和被船員們帶來的外來動物侵擾,也因為他們原本就沒什麼天敵加上防禦力不佳所以最後被趕盡殺絕。
Pyrenean Ibex庇里牛斯高地山羊,在2000年因為捕獵和與優勢動物競爭導致了滅種,在2009年庇里牛斯山羊細胞曾被複製成功,但只存活了幾分鐘的時間,但這卻是復種計畫的一個里程碑。
Carolina Parakeet卡羅來納鸚鵡,是美國東部唯一的一種原生鸚鵡,因為農業擴張和棲地破壞導致卡羅來納鸚鵡數量在十九世紀大量減少,最後一隻卡羅來納鸚鵡在1904年在佛羅里達州被殺。
Woolly Rhinoceros披毛犀(長毛犀牛),有許多辯論懷疑披毛犀的滅絕年代,但最常被接受的是在冰河時期大概10000年前左又消失。現今與之血緣最為相近的物種是極度瀕危的蘇門答臘犀牛。
Moa(Dinornisrobustus)恐鳥,是一種生活在紐西蘭巨大沒有飛行能力的鳥類,體重可達230 公斤。恐鳥在1400年逐漸開始消失,因為毛利人的獵殺和棲地遭農地瓜分和破壞等,最後在1850年代宣告絕種。
Thylacine(Tasmanian Tiger)袋狼(塔斯馬尼亞虎),20世紀初當時大批從英國移民而來的人們為了急速發展農業與畜牧業,除了造成袋狼大量棲地喪失外,飼養羊群的死亡亦嫁禍於這棲居此地萬年之久的本土生物(而事實上都是狗吃掉的)。於是政府在1888年下令懸賞獎勵獵捕袋狼的民眾,從1888年到1941年總計共有2268條袋狼遭到捕殺。最後一隻野生袋狼於1939年死與非命,而最後一隻動物園豢養的袋狼則在1948年死去,但是至今關於發現袋狼的消息仍時有耳聞。
e.張捷:更格盧鼠的生態習性為何?群居或是單獨生活?
Ans. 棲息在略有草叢的乾燥或半乾燥地區,喜歡開闊地。喜歡沙浴,會挖掘洞穴居住,夜行性,一晚覓食距離可達350公尺,食物包括種子、果實、葉、莖、芽和昆蟲等,有儲食行為,通常不喝水,而是利用晚上活動、從食物中獲得水分。族群密度每公頃3.5~17.5隻,通常單獨活動,有領域性,環境好的地區終年可生殖。
u心得感想:撰寫人為導讀人,張捷。
&&& 很開心這個學期有機會參與生態演化讀書會。雖然我一開始是以講師身份參加,但在整個過程中我卻比較像是學員的角色,我在這個讀書會中所學到的比給出的建議還要多得多。隨著一次又一次的讀書會,我們繼續翻譯來自國外的文章,每一位成員的興趣與翻譯文章主題都大相逕庭,但這也恰恰反映了現今國內外的生物多樣性,每一個報導都令人大開眼界。以導讀人的角度來說,我提供了討論時的邏輯思考方向,也因為我的專長,在分子遺傳方向也給了一些新研究的資訊。過程中也確實見證學員的報告有所進步,對於討論中可能有的提問也都做了一定程度的準備,這是相當值得高興的,也達成了讀書會最主要的目的。在學期初的心得中提到希望除了翻譯以外,我們也可以給一些台灣本地的生態資訊,或是實際參加生態保育活動。恰好讀書會後期開始有比較多保育相關的主題,部分成員就與&寶島淨鄉團&一同到香山濕地淨灘,和&荒野保護協會&一起幫青蛙過馬路;部分成員也開始關心並傳遞國內外瀕危物種的保育現況。一次一點點的改變,一次一點點的進步,累積起來的成果是相當可觀的。於是,讀書會成了一個契機,讓我們知道生態保育不只是專業人士、保育團體、生態學者們的任務,而是需要你、我以及身邊每個人的關注。能夠使來自不同學科專長的成員們,都能經由此讀書會喚起對於這塊土地的熱愛,這一點相當難能可貴。因此最後我想謝謝這次的籌辦人兼負責人&曾文宣,給予我們一個討論的機會與空間,讓我們對於生態、演化、保育有進一步的認識,也結識了一群志同道合的朋友們。無論是否有機會繼續接續此讀書會,我相信這次的經驗對於我還有其他成員們都是收獲豐碩,也相信我們的熱情能夠感動身邊更多的人來關心保育議題。
u下一次會更好:
&&& 發現在讀書會的進行過程中有一個很大的問題,因為每次參予的人並不完全一樣,因此當報告者在回答問題時台下上次沒來的人就會不知道問題是甚麼,那種生物又是甚麼東西。也許因為這個原因讓讀書會小組成員討論的效益很有限,雖然在問問題時大家很踴躍很好奇想要了解更多,但是若在後來沒辦法得到答案的話,這樣的學習效果有待改進!
u其他(附件一):組員譯本
a.楊志凱,吃冰讓你頭痛了嗎?
That intense pain, which quickly dissipates, is caused by the dilation and contraction of the internal carotid artery and the anterior cerebral artery when the cold drink/ice cream cools the blood at the back of your mouth. Cold blood equals angry brain.
這個會快速消散的劇烈疼痛是起因於當你在喝冷飲或吃冰淇淋時,會使嘴巴後面的血液變冷,進而導致頸動脈和大腦前動脈的舒張和收縮。冷血就等於憤怒的大腦。
Your brain can't actually feel pain, but the meninges (the outer covering of your brain) has receptors that interpret&the contraction and dilation as pain.
實際上你的大腦不會感覺到痛,但腦膜(大腦外部的覆蓋物)上的受氣會將血管的舒張和收縮解釋為痛覺。
Why are brain freezes important? Because they help scientists understand headaches. Researchers can't give headaches to people just to see what will happen (most people would rather avoid a headache, after all), but brain freezes are quick, easy, and not likely to cause any damage. So
just say it's for science.
為什麼大腦凍結很重要?因為他們可以幫助科學家了解頭痛。研究者不可能只為了觀察頭痛後會發生什麼事而在人身上製造頭痛(畢竟,大多數人會選擇避免頭痛)。但是,大腦凍結很快速、簡單,而且幾乎不會造成任何傷害。所以,享受你的冰淇淋,並說這是為了科學。
Source & Reference
b.呂昱賢,餐桌上的海洋生態浩劫
Shellfish have become a popular seafood dish, but their popularity rests on a tragedy.
貝類已經成為有名的海鮮菜餚,但這樣的產量卻建立在悲劇上。
The collapse of the cod and haddock industries in the UK, USA, and Canada was devastating to fishermen, but shellfish have risen to become the number one marine resource. Why? Cod and haddock are predators, and without predators, the shellfish population has boomed.
在英國,美國和加拿大,鱈魚和黑線鱈漁業消逝(走下坡)危害著漁民,但貝類已經成為頭號海洋資源。為什麼呢?鱈魚是掠食者,沒有天敵,貝類的數量有爆炸性的增長。
This sounds like good news: the fishing industry has continued by relying on booming populations of tasty shellfish. There are significant problems with this scenario, however.
這看似是一則好消息:漁業可以繼續依賴貝類爆炸性的增長為生。然而,這樣的情況卻隱藏著極大的問題。
First, shellfish are particularly vulnerable to ocean acidification from global climate change. Ocean acidification interferes with proper shell formation. Remember DDT's affect on eggshells? Well, a scallop doesn't do well with a weak shell either.
首先,貝類對於全球暖化所造成的海洋酸化很敏感,海洋酸化會影響貝扇的形成,還記得DDT如何影響蛋嗎?同樣的,貝扇也不會有強壯的身體由於脆弱的外殼。
Second, relying on shellfish is like relying on monoculture agriculture: if something goes wrong, it really goes wrong. An ecosystem without predators is at risk of disease and species invasion in the long term.
第二,依靠貝類為生就如同依靠單一作物為生:如果出現錯誤,它真的就完蛋了。沒有天敵的生態系統由於疾病和物種入侵處在危機中。
The Black Sea, Baltic, and west coast of Africa have already seen the result of an ocean without predators: the loss of large predators in these areas have led to jellyfish explosions. Oxygen depletion and large quantities of hydrogen sulphide have destroyed the local ecosystems.
在黑海、波羅的海與非洲西海岸皆發現海洋缺乏捕食者的問題:缺乏大型掠食者造成水母爆炸性的增長。因此,氧氣枯竭和大量的硫化氫破壞了當地的生態系統。
Professor Callum Roberts says &We need more marine protected areas to stop our seas from becoming a wasteland and to restore the diversity and productivity of fisheries well into the future.&
卡魯姆&羅伯茨教授說:「我們需要更多的海洋保護區來防止我們的海洋成為一片荒地,並且在未來恢復海洋的生物多樣性和數量。」
Source & Reference
c.王品惠,進擊的蟲草!
The Walking Dead. Based on a true story.
行屍走肉,這是根據一個真實的故事&&。
Ophiocordyceps unilateralis, also known as cordyceps, is a type of fungus that infects insects and takes over their nervous systems. The method with which they take control of nervous systems is still a mystery to science. However, the repercussions of such an infection are all too clear.
Ophiocordyceps unilateralis(偏側蛇蟲草菌),又稱「蟲草」,是一種會感染昆蟲並接管牠們神經系統的一種真菌。這種真菌是如何控制神經系統至今仍是科學界裡的一個謎。但是這樣感染的結果被研究、觀察地很透徹。
Carpenter Ants, for example, live in the canopy of the tropical rainforest. They frequently forage for food on the forest floor. Unfortunately, this is where the cordyceps fungus proliferates. A new study shows that the fungus prefers to grow on &the undersides of leaves sprouting from the northwest side of plants that grow on the forest floor& This places it in an ideal position to grow and release its spores to infect ants. Here's how the fungus gets there in the first place.
例如弓背蟻(或屈背蟻、木匠蟻),住在熱帶雨林的樹冠上。牠們經常在雨林的地面層覓食。不幸的是,這裡同時也是蟲草真菌增生的地方。一項最新的研究指出這些真菌喜歡生長在「西北側雨林地面層的植物葉子下表皮」上。這是個能夠生長且釋出孢子來感染螞蟻的理想位置。首先,以下敘述將告訴你這些真菌是如何抵達這個地方。
When an ant is infected by cordyceps, it undergoes a series of behavioural changes. The fungus forces the ant to climb down from the canopy to the low leaves where the cordyceps prefers to grow. Just before dying, the ant will use its mandibles to bite down on the leaf to secure itself.
當一隻螞蟻被蟲草感染了之後,牠會遭逢一連串的行為遽變。真菌會迫使螞蟻從樹冠往下爬到牠們(蟲草)喜歡生長的矮葉上。在死之前,這隻螞蟻會用牠的下顎來緊咬葉脈來保護牠自身的安全。
After the zombie ant dies, the fungus digests the insides of the ant to get nutrition for growth. It&s interesting to note that the cordyceps avoids digesting the muscles controlling the ant&s mandibles. These muscles are the ones that keep the ant attached to the surface. The outer husk of the ant is also left unharmed. The cordyceps uses this as a physical armor to protect against microbes and other fungi.
在殭屍螞蟻死去之後,真菌會消化螞蟻的身體內部來獲得成長的營養。注意到有趣的是這些蟲草會避免消化到控制下頜骨的肌肉。這些肌肉的功能是使螞蟻能夠維持緊貼在葉子表面上。螞蟻的外骨骼結構也不會被蟲草侵蝕。 蟲草利用了這些物理裝甲來防護其他微生物或真菌的入侵。
The fruiting body of the cordyceps will then erupt from the ants head, slowly growing longer until it matures, after which it will release the spores, which seek new hosts. Any ant in the vicinity of this event risks infection.
接著蟲草的子實體將會從螞蟻的頭部爆開來,慢慢地越長越長。直到牠成熟之後,牠會釋出孢子來尋找新的宿主,任何位於附近的螞蟻都有被感染的風險。
A single ant infection is a threat to the whole colony. As such, ant colonies go out of their way to avoid an epidemic. Worker ants will often carry an infected ant far away from where the colony forages to prevent the spread of the fungus. The fact that Carpenter Ants live in the canopy of the rainforest may be a strategy to escape the infection.
一隻被感染的螞蟻對整個螞蟻棲息地來說是一個極大的威脅。因此,螞蟻棲息地會走出自己的路來避免疫情的發生。工蟻時常將被感染的螞蟻搬運到離棲息地十分遠的地方來防止真菌的傳播。事實上,弓背蟻會住在雨林的樹冠上或許是一項避免被感染的策略。
Cordyceps does not exclusively target Carpenter Ants. There are many different types of Cordyceps fungi that can infect many different insects, including moths, grasshoppers and many more.
蟲草並沒有專門針對弓背蟻。有許多不同的蟲草真菌,可以感染很多不同的昆蟲,包括蛾,蚱蜢及諸多類型。
Source & Reference
影片連結:
d.林郁庭,鯨魚死掉之後
After its death, a whale's remains play host to a strange ecosystem that we know very little about. For the first time, scientists have discovered a whale skeleton on the Antarctic seafloor and with it, 9 new species.
鯨魚即使死亡之後,在一個我們陌生的生態系統中依然扮演著宿主的角色。科學家第一次在南極海底中的鯨魚骨頭上發現了九種新物種。
When a whale dies, its body sinks to its final resting place (known as a whale fall). The size and depth of the oceans mean you'll only find one if you happen to be right above it with an underwater vehicle and as such only six natural whale falls have been found. The bones of this southern Minke whale, located nearly a mile under the Antarctic surface, provide an important insight into how the ocean recycles its giants.
當鯨魚死掉後,牠的身體會沉到海底,這個過程又叫作whale fall。除非你剛好在鯨魚屍體的正上方並且剛好有水下的載具,你才能在遼闊的海洋中找到鯨魚屍體,所以目前只有發現六個天然的whale falls。這隻南極小鬚鯨的骨頭位於南極地底深約一英哩的地方,可以看出海洋是如何將這龐然大物回收再利用。
A whale's carcass is stripped relatively quickly - due to scavengers and decomposition, after a very short time almost all that will remain of the whale will be its bones. For some organisms, these are enough. Despite the Minke bones being decades old, the team found corals, snails, worms, limpets and new species of isopods (woodlouse-like arthropods) and &zombie worms& on them.
鯨魚的屍體很快就被清除者吃光和分解掉了,所以在極短的時間內鯨魚就會只剩下骨頭。對一些物種來說這樣就足夠了。儘管小鬚鯨的骨頭已經幾十年了,研究團隊在骨頭上依然發現珊瑚、蝸牛、蟲子、帽貝以及等角類的新物種(類似潮蟲的節肢動物)和食骨蟲。
This discovery comes shortly after another study revealed more about the development of the bone-eating zombie worms (of the genus Osedax). They feed by excreting acid onto the bone, boring a hole (rather than being whale specialists, they seem to eat all vertebrate bones). Six weeks after finding bones the females mature and then continuously release eggs, fertilized by the diminutive males. After hatching the microscopic larvae can swim for 10 days to find a carcass of their very own.
在另一個研究揭露出更多有關食骨蟲(食骨蠕蟲屬)的發展後不久就有了這項發現。牠們藉由分泌酸液在骨頭上鑽出小孔洞來進食,(牠們似乎會吃全脊椎動物的骨頭,不只鯨魚)。發現骨頭後的六周雌食骨蟲就成熟了,並開始產卵,由極小的雄性授精。經過孵化的小幼蟲可以自己獨立游十天好找到一具屍體。
Source & Reference
食骨蟲相關:
e.林郁庭,吃骨頭的鼻涕花
Osedax mucofloris (literally &bone-eating snot-flower&) dissected from whale bone.
照片中是從鯨魚骨頭中解剖出來的Osedax mucofloris,字面上的意思為吃骨頭的鼻涕花。
New research on bone-eating zombie worms raises as many questions as it answers...
關於食骨蟲的新研究雖然回答了我們的疑問卻也同時引起了很多問題。
Zombie worms (scientifically known as members of the genus Osedax) have an important role in marine ecosystems. When whales and other vertebrates die they are one of many organisms that live off the carcass, occupying the very rare niche of living off the bones. &Bone-eater& is the literal meaning of Osedax.
食骨蟲是食骨蠕蟲屬(Osedax),在海洋的生態系統中扮演很重要的角色。當鯨魚或是其他脊椎動物死亡時,食骨蟲便是眾多住在屍體中生物的其中一員,占有個相當稀有的生態棲位。食骨蠕蟲字面上的意思就是食骨者。
To get to the juicy nutrients locked inside the skeleton, the worms dissolve the bones using acid. This acid, produced by their skin, is created by proton pumps at the front of the worm. When the bone is dissolved, it's thought the worms absorb the released collagen and lipids. Intriguingly, the worms' acid is almost identical to the acid produced by osteoclasts - cells that break down bone so it can be reabsorbed and rebuilt.
為了得到在骨頭中的豐富營養,蟲蟲們會用酸來溶解骨頭。酸液是由質子幫浦產生,再從他們的皮膚分泌出來。當骨頭溶解後,一般認為蟲蟲們會吸收釋放出來的膠原和脂質。有趣的是,蟲蟲的酸液和蝕骨細胞所產生的酸液幾乎相同,蝕骨細胞是將骨頭分解的細胞好讓其重新被吸收再重建。
It's all very well saying these worms live off bone, but how? Not only do they not have mouths, they also have no digestive system. It's not yet known how they &digest& the nutrients they release. It's likely the bacteria that live in the worm play a role, and some evidence has suggested the bacteria break the collagen down into other compounds which are then absorbed by the worm.
大家都說這些蟲蟲以骨頭為生,但是他們是如何做到的?食骨蟲不只沒有嘴巴,他們也沒有消化系統。現在還不知道他們是怎麼將骨頭中的養份消化掉的,可能是住在蟲蟲身體中的細菌所幫的忙,而且有些證據顯示在細菌將膠原分解成其他物質後,食骨蟲確實吸收了這些物質。
Source & Reference
f.林芝蘭,歐卡歐卡鯊人鯨
Orcinus orca, commonly known as the Killer Whale, is the largest species of dolphin in the world. The dorsal fin alone can grow to be taller than an adult human. Despite their size, they are by no means slow or stupid. They can reach 55km/h underwater and employ incredibly smart tactics when hunting. They are amongst the only animals that will hunt and eat whales. Killer Whales are known to beach&themselves on purpose (a dangerous maneuvre) to catch their prey by surprise. Once the prey is caught, they do not kill them immediately, but bring them back for their children to practice hunting with.
Orcinus虎鯨,又俗稱殺人鯨、逆戟鯨,在世界上是最大的海豚品種。僅背鰭可以長到比成人高。儘管牠們的體型龐大,他們絕不緩慢或愚蠢。他們可以在海面下以速度達到55公里每小時,水下狩獵時,會使用非常聰明的戰術。他們是唯一會狩獵並吃鯨魚的動物。逆戟鯨會趁獵物不注意捕捉他們,使其措手不及。一旦捕獲獵物,牠們不立即殺了牠們,而是把他們帶回給自己的孩子練習狩獵。
They have long lives. Whilst male Killer Whales only live to their 50s, female Killer Whales can survive well into their 90s. Yet, they are unable to reproduce after their 30s and 40s. This equates to them having the longest menopause of any non-human species. The reason for their obscenely long menopause was unknown until quite recently. As it turns out, the mother is able to care for her adult children well after menopause. A study shows that in the absence of a mother, the likelihood of death for the adult son increases 14 times. In the words of Dr Dan Franks, &Our analysis shows that male killer whales are pretty much mommy's boys and struggle to survive without their mother's help.&
他們有很長的生命。雖然雄性虎鯨只能活到50多歲,女虎鯨可以生存到90多歲。然而,他們無法在30歲和40歲後繁衍下一代。這相當於他們是具有最長更年期的非人類物種。造成他們如此長的更年期的原因是未知的,但直到最近。事實證明,母親是在更年期後依然能夠照顧她的成年子女。一項研究表明,在有母親的情況下,成年的幼鯨死亡的可能性會增加14倍。在丹&弗蘭克斯博士的話說,&我們的分析表明,雄性虎鯨很多是有母親的且在沒有母親的幫助下為生存而掙扎。&
It's interesting that while humans have evolved menopause to allow for women to care for their grandchildren, female killer whales only seem to care for their own offspring.
有趣的是,雖然人類已經進化到更年期後的婦女仍可照顧他們的孫子,女殺手鯨似乎只關心自己的下一代。
Source & Reference
g.張捷,鐵球知多少?
Previously, it was hypothesized that iron-rich cells in pigeon beaks helped them to orientate themselves to the Earth&s magnetic field. However, research done by the Keays lab at the Research Institute of Molecular Pathology in Vienna showed that they were really just blood cells, which naturally contain iron.
早先的研究者推想鴿子能夠利用地球磁場來導航,是藉由牠們的喙中一些富含鐵離子的細胞的幫助。然而,來自維也納分子病理研究院Keays實驗室的研究者們表示,這些含鐵的細胞其實就是原本就含有鐵質的血球細胞。
However, further studies done by the same lab have resulted&in the discovery of microscopic balls of iron in the sensory neurons of birds. These iron balls are found in all birds, be it flightless or not. The sensory neurons in which they are present, are known as &hair cells&. These hair cells are used to detect sound and gravity. The presence of these iron balls in these sensory neurons is a truly exciting revelation. However, it is not confirmed that these iron balls are the magnetoreceptors that help birds orientate themselves to magnetic fields.
但是,同個實驗室的最新研究指出,他們在鳥類的感覺神經元中發現微米級的小鐵球。這些小鐵球在鳥類中普遍存在,無論牠們是否會飛行。含有這些鐵球的細胞就是我們所說的毛細胞,在體內是用於感受聽覺與重力(平衡)。雖然目前還沒有證據顯示感覺神經元內的鐵球與使用地磁導航有直接關聯,但是這些小鐵球的發現無疑 是個令人興奮的啓示。
Source & Reference
鳥類毛細胞小鐵球:
h.張捷,非先天決定一切!
Most of us have met identical twins and we understand that though they may be genetically identical, they are two unique individuals. But how can two people who share the same genes and the same environment be so different?
相信大部分的人都遇過同卵雙生雙胞胎,儘管知道他們在遺傳因子上完全相同,但我們仍會認為他們分別是兩個獨立的個體。然而,為什麼兩個擁有相同基因的人,甚至生活在相同的環境,仍然會有所不同呢?
Researchers are intrigued by identical twins because they bring up the old nature vs. nurture dilemma. However testing human identical twins in a laboratory setting isn't possible. That's where mice come in.
學者們一直以來都為同卵雙生雙胞胎的異同感到好奇,這樣的差異也回歸到了&先天 vs. 後天&影響個體的老問題。我們無法在研究上直接對同卵雙生雙胞胎的人類進行實驗,但是我們可以使用其他的生物做為實驗平台,實驗用小鼠就是一個例子。
Researchers, led by Gerd Kempermann of the Center for Regenerative Therapies Dresden in Germany, studied 40 genetically identical female mice. They placed the mice in identical mazes and studied how much the mice explored. Later on, the researchers cross sectioned the mice brains and looked at the differences in the hippocampus (the part of the brain responsible for navigation and memory) between mice. The researchers found that the mice that explored more had more neurons in the hippocampus.
來自德國德勒斯登再生醫療中心的Gerd Kempermann研究團隊試圖來回}

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