Ob sab symmetry yog tib qho kev npaj ntawm lub cev ntawm cov kab mob nyob rau sab laug thiab sab xis ntawm ob sab ntawm lub hauv paus axis lossis dav hlau. Figuratively hais lus, yog tias koj kos ib kab ntawm lub taub hau mus rau tus Tsov tus tw ntawm lub cev - ob sab yog daim iav duab ntawm ib leeg. Nyob rau hauv cov ntaub ntawv no, lub cev nthuav tawm ob sab symmetry, uas tseem hu ua planar symmetry, vim hais tias ib lub dav hlau faib cov kab mob mus rau hauv daim iav-duab halves. Peb yuav kawm tag nrho txog kev sib koom ua ke ntawm ob sab thiab saib qee qhov piv txwv. Peb tseem yuav tham txog cov txiaj ntsig tseem ceeb.
Symmetry txhais
Symmetry yog cuam tshuam nrog kev taw qhia ntawm lub cev raws li lub dav hlau lossis ib puag ncig ib qho axis. Muab cov duab sib txawv thiab kev taw qhia ntawm cov kab mob sib txawv, cov kws tshawb fawb tau los nrog peb hom kev sib luag:
- thawj hom yog radial symmetry. Nrog rau hom no, lub cev txoj kev npaj yog nyob ntawm axis. Hauv lwm lo lus, lub cev yog taw qhia kom nws rov qab los ntawm txoj kab kev xav los ntawm qhov nruab nrab ntawm lub cev. Cov kab mob no muaj ib sab saum toj thiab hauv qab, tab sis lawv tsis muaj sab laug thiab sab xis, pem hauv ntej thiab nraub qaum. Ob peb piv txwv ntawm radial symmetry yog cov ntses hnub qub, jellyfish thiab hiav txwv anemones.
- Muaj qee yam kab mob uas tsis pom kev sib luag. Lawv raug cais raws li asymmetrical. Tsuas yog cov tsiaj uas muaj tiag tiag ntawm qhov kev faib tawm no yog sponges.
- hom kawg ntawm symmetry yog ob sab symmetry. Qhov no yog thaum lub cev npaj tau muab faib raws lub dav hlau uas faib cov tsiaj lub cev rau sab xis thiab sab laug, uas yog daim iav duab ntawm ib leeg. Wb saib hom symmetry no me ntsis ntxiv.
Piv txwv ntawm ob sab symmetry
Yog li tam sim no koj tuaj yeem xav txog cov tsiaj sib txawv uas nthuav tawm ob sab symmetry. Txiv neej yog thawj tus piv txwv uas peb yuav tham txog. Yog, peb tib neeg yog ib qho piv txwv ntawm ob sab symmetry. Qhov no tuaj yeem pom yooj yim heev. Mus saib daim iav thiab pom koj tus kheej. Peb tuaj yeem kos ib txoj kab ncaj nraim hauv nruab nrab ntawm koj lub cev, sab xis ntawm koj lub qhov ntswg, thiab faib koj mus rau sab xis thiab sab laug daim iav duab. Txawm tias koj lub hlwb tuaj yeem muab faib ua sab xis thiab sab laug.
Cia peb saib lwm tus piv txwv. Koj puas muaj dev lossis miv? Lawv kuj muaj ob sab symmetry. Lwm yam piv txwv uas kojTej zaum lawv tsis xav tias - cov no yog sharks, npauj npaim thiab ntsaum.
Bilateral Symmetry Benefits
Yog li muaj qee qhov txiaj ntsig tiag tiag rau ob tog sib luag. Qhov tseeb tias peb muaj ob lub qhov muag thiab pob ntseg txhais tau hais tias peb tuaj yeem pom thiab hnov ntau dua li cov tsiaj txhu sib luag. Ob sab symmetry kuj coj mus rau qhov tsim ntawm lub taub hau thiab tus Tsov tus tw cheeb tsam. Qhov no txhais tau hais tias txhua yam tuaj yeem mus rau hauv ib qho kawg thiab tawm mus rau lwm qhov, tsis zoo li cov kab mob uas yuav tsum tau siv tib qhov qhib. Yog tsis nkag siab ntau dhau lawm ces cia hais tias peb sawv daws zoo siab heev li.
Lwm qhov txiaj ntsig yog qhov kev sib luag ntawm ob sab tso cai rau kev txhim kho ntawm lub paj hlwb ntau dua uas tuaj yeem tswj tau lub cev. Ntau tus tsiaj muaj ob lub cev sib luag, uas txhais tau hais tias lawv tuaj yeem muab faib ua ib nrab los ntawm kev kos ib kab hauv nruab nrab. Hauv qhov kev hwm no, arthropods tau tsim zoo li tib neeg: sab xis ib nrab ntawm arthropods yog daim iav duab ntawm sab laug ib nrab. Qhov no yog ob sab symmetry.
Bilateral thiab radial symmetry
Txhua tus tsiaj nyob hauv ntiaj teb nthuav tawm ob sab symmetry. Nov yog yam uas tib neeg muaj. Nws txawv ntawm radial. Radially symmetrical kab mob zoo ib yam li cov duab ntawm lub ncuav qab zib, qhov twg txhua feem yuav luag zoo tib yam, txawm tias lawv tsis muaj sab laug lossis sab xis. Hloov chaw, lawv muaj qhov saum npoo thiab hauv qab. kab mob uasqhia radial symmetry, xws li corals, jellyfish thiab hiav txwv anemones, hiav txwv urchins thiab starfish.
Txheej Txheem ntawm Ob Sab Sib Nrauj Cov Kab Mob
Cov kab mob uas muaj ob tog sib luag qhia pem hauv ntej thiab nraub qaum, sab saum toj thiab hauv qab, thiab sab laug thiab sab xis. Lawv nyiam txav nrawm dua li cov tsiaj uas tsis muaj kev sib koom ua ke ntawm lub cev. Nws kuj tseem txhim kho lub zeem muag thiab hnov lus piv rau cov uas muaj radial symmetry.
Yeej tag nrho cov kab mob hauv hiav txwv, suav nrog txhua tus vertebrates thiab qee qhov invertebrates, yog ob sab sib luag. Qhov no suav nrog cov tsiaj hauv hiav txwv xws li ntses taub ntswg ntev thiab whales, ntses, lobsters thiab hiav txwv vaub kib. Interestingly, ib co tsiaj muaj ib hom ntawm lub cev symmetry thaum lawv thawj lub neej, tab sis lawv loj hlob txawv thaum lawv loj hlob.
Muaj ib tug tsiaj qus uas tsis pom kev sib haum xeeb: daim txhuam cev. Cov kab mob no yog multicellular, tab sis nyob twj ywm tib yam asymmetric tsiaj. Qhov no txhais tau tias tsis muaj qhov chaw hauv lawv lub cev uas koj tuaj yeem faib lawv ua ib nrab thiab pom daim iav duab.
