terrestrial adaptations in reptiles.pptx

8/21/2019 TERRESTRIAL ADAPTATIONS IN Reptiles.pptx

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TERRESTRIAL ADAPTATIONS INREPTILES


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Reptiles evolved from their water-dwellingancestors and moved to land during thePaleozoic era, over 280 million years ago.

They dominated the earth etween 2!8 and 2"#million years ago and live on today as modern-

day sna$es, turtles, lizards, crocodiles, etc


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%uring this great stretch of time the reptilesevolved into multitude of forms.

&ome '( million years ,at the end of )retaceousperiod ,the dinosaurs vanished , possily ecause of a dramatic change of climate.

*ost of the reptiles that survived the+catastrophe were in general , less spectacularanimals li$e lizards and sna$es. These animalsflourished due to many adaptations and ma$eupthe ul$ of the around 000 species of reptilesthat eist today.


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*ost important factor in evolution of reptiles was the development of tough , dry, scalyimpermeale s$in which prevented themfrom drying , dessication and physical in5ury.

&$in has a thin epidermis which is shedperiodically and a lower much thic$erdermis. &cale is made of $eratin. &cales are

of different types6 granular7appear umpy ,$eeled 7have a centre ridge ormodified into scutes eample crocodile


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Reptilian 9/:& are efficiently designedapplying crushing or gripping force on theprey. The 5aw muscles have ecome larger,

longer and arranged for much ettermechanical advantage.


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Reptiles have evolved efficient strategies for water conservation ;*any reptiles have salt glands located near the nostrils, eyes

or in tongue .)helone and salt water crocodile secretes a

salty fluid that is strongly hyper osmotic to the ody fluids.

4itrogenous wastes are ecreted as uric acid which has low

soluility and precipitates easily, allow in water to econserved.

The urine of many reptiles is a semi solid suspension.


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Reptiles don


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To cool its ody reptiles opens its mouth andincrease its reathing rate ,lizards increases its reathing rate from normal #" reaths=minute to""! reaths=minute.

%uring winter they lie dormant either alone or ingroups ,during which they stop eating and lower

their metaolic rate.


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/ll Reptiles ecept limless ones ,have etter ody support than amphiians andmore efficiently designed lims formovement on land .Reptiles legs are

directed down towards the ground, whichallows them to pic$ their ellies off theground to move fast.


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4ervous system of Reptiles is consideraly more complethan amphiians. )ererum is large in relation to rest of the

rain. )onnections to the )4& are more advanced ,permittingcomple ehaviour. :ith eception of hearing ,sense organsin general are well developed. 9acosons organ a specialized

olfactory structure is highly developed in lizards and sna$es.>dours are carried to 9acosons organ y the tongue.Theyalso help in detecting presence of water and also mate.


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The main function of smell has een reroutedfrom the nose to the tongue. :hen a lizard or asna$e wants to smell it


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The head of some sna$es li$e pit viper,python and oas have heat sensitiveorgans or pits that enale them to detectminute variations in heat, especially thechange in air temperature y the presence of warm-looded prey.


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)amouflage

*any reptiles use camouflage for defense as well as to conceal themselves from prey .


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n provide some clues to what reptiles see, and when they hunt. Reptiles with round pupils are usually active during the day, and probably see in color. Slit-like pupils are common in nighttime predators, wh


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Reptilian eye is similar to that of other verterates. izards,turtles and &phenodon have a numer of ony plates insidethe eyes ,that enale them to focus well.

izards have good eye sight ecause colors are an importantguide in mating and hunting.

*ost sna$es have poor eye sight ,since they rely on smell totrac$ their prey .

Pupil shape and eye position provide some clues to whatreptiles see and what they hunt. Reptiles with round pupilsare usually active during day and proaly can see colors.&lit-

li$e pupils are common in night time predators ,which have lac$ and white vision.

n provide some clues to what reptiles see, and when they hunt. Reptiles with round pupils are usually active during the day, and probably see in color. Slit like pupils are common in nighttime predators, wh


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Reptilian lungs are consideraly more complethan those of amphiians, showing internalpartitioning to provide additional surface areafor gas echange etween lung gas and lood.Reptiles depend almost eclusively on lungsfor gas echange ,supplemented y respirationthrough pharyngeal memranes and cloacallining as seen in some a?uatic forms li$e

chelones.

http://www.britannica.com/EBchecked/topic/445221/partitioninghttp://www.britannica.com/EBchecked/topic/445221/partitioning


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The circulatory system of a reptile, li$e thoseof all terrestrial verterates, is composed oftwo loops. The pulmonary loop carriesdeoygenated lood from the heart to thelungs and returns oygenated lood to theheart. The systemic loop transportsoygenated lood to the tissues of the ody, where oygen and nutrients are unloaded and where caron dioide and wastes are pic$edup, and returns deoygenated lood to theheart.


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*ost reptiles lay amniotic eggs covered with leathery orcalcareous shells. /n amnion , chorion, and allantois arepresent during emryonic life. The shell protects and $eepsit from drying out, ut it is fleile to allow gas echange. The

chorion aids in gas echange .The alumin serves as areservoir for water and protein. The allantois collects themetaolic waste produced y the emryo. The amniotic sac

with amniotic fluid which protects and cushions the emryo.The amnion aids in osmoregulation .The yol$ sacsurrounding the yol$ contains protein and fat rich nutrients

that are asored y the emryo. The air space provides theemryo with oygen while it is hatching. This ensures thatthe emryo will not suffocate while it is hatching.


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Reptiles lay the eggs in a sheltered location on land. @ggs are uried in ground in nest, no parental care seen.

3n crocodiles, some turtle families, and some lizards, nesttemperature determines se of offspringA low temperaturesare males and higher temperatures are females

The appearance of large shelled egg widened the division etween the amphiians and reptiles ,this contriuting factorplayed a role in evolution of reptiles.


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