Topics in BiologySkeleton and Type of Skeletal Materials Bones and Types of Bone Bones and Type of Bone part 2 Red Blood Cells and Hemoglobin Tropical Rainforest and Savanna with their characteristics Desert and Swamp Forest with their characteristics Autotrophic mode of Nutrition Amazing facts in Biology Characteristics of Protists Characteristics of Reptiles
Academic Questions in Biology
Chemical digestion of carbohydrate (cooked starch) begins in the _____.
ANSWER is Mouth
The digestion of carbohydrate (cooked starch) begins in the mouth through an enzyme called salivary amylase (formerly called ptyalin) found in the saliva. This enzyme breaks down the starch present in carbohydrates into maltose. Maltose is a disaccharide. Please read on sugars and disaccharide here.
Note: With regards to digestion, chemical digestion is emphasized. We also have mechanical digestion which involves the grinding action of the teeth.
Reptiles are vertebrate (animals with backbone) that belong to the class reptilia. In Latin, reptile means creeping animals. It is believed that reptiles evolved from a certain vertebrate called reptiliomorph, more than 300 million years ago. They were initially aquatic animals and with time they became adapted to the terrestrial habitat (land). Some reptiles hibernates while others brumate. During hibernation, an organism stays in a sleep-like state without food for a long period of time, surviving from its fat reserve. Brumation on the other hand is similar to hibernation except that the animals are neither asleep nor live off their fat reserve, rather their metabolic processes become very reduced resulting in the sluggishness of such animals.
In this article, we will look into the various characteristics or features of reptiles.
An animal is said to be a vertebrate if it has a backbone. Reptiles, fishes, toads, birds and mammals are all vertebrates. The backbone of reptiles begins from the lower end of the skull and runs throughout their body length. Running inside the backbone is the spinal cord which constitutes a part of the central nervous system.
Reptiles cannot physiologically regulate their body temperature. To explain this, think of humans who have got a defined body temperature of about 36.5oC. This stability in temperature is made possible in humans via a process called homeostasis, regardless of where they may find themselves (cold or warm conditions). Read our article on homeostasis HERE. In the case of reptiles, the weather condition determines their temperature. When it’s warm, their temperature increases and when cold, it decreases. When the weather becomes too hot, they tend to move into shady places or water in order to lower it. Their body temperature is therefore dependent on their environment.
Note: Although most enzymes work best at a specific temperature, that isn’t the case in reptiles. Their metabolic enzymes can work efficiently over a wide range of temperatures.
Unlike mammals whose bodies are covered in hair/fur or birds whose bodies are covered in feathers, all reptiles have their bodies covered in scales or scutes which protects them from the dangers of their external environment. The chelonians which includes reptiles like turtles and tortoises in addition to having scales also possesses a hard protective shell (called carapases) that gives an extra protection to their upper bodies. The scales are composed of keratin and can either be tubular or ossified in appearance. In addition to providing protection and movement, the scales prevent loss of water to the environment and this is one reason while some reptiles can survive in deserts. The scutes are different from scales because give more protection and appear more like a dermal armor. They are found in tortoises, turtles and crocodiles.
Most reptiles are oviparous animals. This imply that they lay eggs which are covered in shell. A few are ovoviviparous (that is, the eggs remain in the mother’s womb until they are ready to hatch) while others are viviparous, meaning that the young ones are born alive. Some reptiles will incubate their eggs either by laying on them or by burying them below the earth until they hatch. Some will look after their young ones but only for a short period of time.
Moulting is a process where animals shed their skin. This process or moulting is apparent in insects and reptiles. They remove the uppermost layer of their skin each time it gets worn out. Parasites on their skins are also removed through this process. Lizard shed their skins in patches while crocodiles shed the individual scales.
Other characteristics of reptiles includes
They Respirate is via the Lungs.
They have three chambered heart.
Most are tetrapods (have four legs). Snakes are exceptions.
Most are carnivores with the exception of turtles and tortoises which feed on plant.
They are not hermaphrodites; that is, the male and females are separate.
Amazing facts in Biology
An adult human being is composed of about 60% water. In fact, a newly born baby is composed of about 80% of water. This will drop to 65% after a year and finally to about 60% as the child ages
Without saliva, food can never be enjoyed. Food becomes tasteless since saliva is needed to dissolve the chemicals present in food onto the tongue’s taste buds.
Saliva also contains an enzyme called salivary amylase or "ptyalin" which helps to digest cooked starch to maltose. Maltose is a double sugar or disaccharide. Please read on sugars here
NOTABLE POINTS IN Biology
The gas used in the manufacture of food by plants is Carbon dioxide or Carbon(IV)oxide or CO2.
Plants manufacture food through a process called photosynthesis. Please read on photosynthesis here
Note: Plants are the only orgnisms that take away CO2 from the atmosphere
In the Biological organization of life, it is said that cells form tissues, tissues form organs and organs form systems. There are 12 systems in the human body; these are: