PLATYPUS - THE EGG-LAYING MAMMAL

PLATYPUS

Genus: Ornithorhynchus
Species: Ornithorhynchus anatinus
Kingdom: Animalia
Class: Mammalia

Platypus is a unique Australian species. It is considered as a separate order of mammals, called monotremes, which are distinguished from all other mammals as they lay eggs.

HABITAT:

GEOGRAPHICAL LOCATION

 

Platypus generally lives in rivers and streams with gentle flow of water and lots of aquatic vegetation. They are mostly found in the freshwaters of Northern Queensland, and even in the cold, high altitudes of Tasmania and the Great Dividing Range. They often burrow under the roots of vegetation near the river banks.

 

 

 

STRUCTURAL ADAPTATIONS:

STRUCTURAL ADAPTATIONS OF A PLATYPUS

DUCK-BILLED PLATYPUS

Platypus is well-adapted to the aquatic environment. It has a streamlined body and a flat tail, which are covered with thick water-proof fur. While moving in water, platypus uses its front webbed-limbs and the hind limbs, along with its tail are used to control speed and to change directions while swimming.

Another important adaptation of the platypus is its bill. The bill, not only helps the platypus to find and digest

food, but it works as an electroreceptor, which detects the minute movements made by its prey, without using the eyes and ears.

SPUR NEAR THE ANKLE

There is a spur near the ankle of a platypus, both in males and females. The females shed off their spur at an
early age, while the males produce venom in their spurs.There is a kidney-shaped gland, called crural gland, present in the upper thigh, which produces this venom. This spur protects the platypus from its predators, otherwise it lies flat against the limb.

  

BEHAVIORAL ADAPTATIONS:

 

A platypus is mostly active at night and sleeps in the day. This has protected the animal from its predators, as most of them are day-hunters. Platypus is not comfortable in walking on dry lands because of its awkward webbed feet. While swimming, only a little part of its head, back and tail are visible above the water surface as three small humps.

EGGS OF A PLATYPUS

A platypus is generally shy in nature. While mating in winter, the males initiate courtship, with some aquatic

activities like rolling sidewise in water, touching and often the males grasping the females' tail with their bill. The process even lasts for more than half-an-hour. After mating, they dig burrows near the soft river banks  in sake of protection of the pregnant mother and her eggs. Normally a female platypus lays 1-3 eggs, which are quite similar to the eggs of reptiles. Then she incubates the eggs with her belly and tail.

BABY PLATYPUS

When the youngs hatch , the mother produces milk and feeds its babies with its two milk patches present in her abdomen covered with fur. The mother spends most of the time in feeding and growing her babies. Towards the end of summer, the babies crawl out of the burrow as an independent animal.

PHYSIOLOGICAL ADAPTATIONS:

 

The males are larger than the females with a size  ranging between 40 and 63 cm. while in females, it is between 37 and 55 cm. The weight is about 800 gm. to 3 kgs. in males while the females weigh between 600 to 1700 gm. A platypus has a lower basal temperature than other mammal;s which is around 32 degree Celsius. In the cold winter times, it reduces the flow of blood in the bare parts of its body. By doing this, it protects its vital organs from being chilled. However, a platypus remains active throughout the year.

SAGUARO - THE GIANT CACTUS

SAGUARO CACTUS

Genus: Carnegiea
Species: Carnegiea gigantean
Family: Cactaceae
Class: Magnoliopsida, Dicots
Average Height: 30 feet

GEOGRAPHICAL LOCATION

LOCATION:

Found especially in a rocky terrain of a desert, the Saguaro Cactus is mostly found in the hot, dry climate of Sonoran Desert in the south-western part of North America. It is common in south-west of Arizona, south-east of California anad in the Sonoran state of Mexico.








GENERAL ADAPTATIONS:

SPINES ON THE STEM

The saguaros with their structural modifications are well-adapted to the natural conditions provided by the Sonoran Desert. The thick epidermis and waxy cuticle of Saguaro prevent loss of water by transpiration. So the transpiration only takes place by the stomata, when are open. The two-inch spines located on the trees vertical ribs protect Saguaro from the desert animals which would otherwise use it to meet their water requirement. Even the spines protect the sensitive tip of the plant from extreme heat or cold. The Saguaros have more numbers of parenchyma cells than other plants to help water retention. The stem of the plant can be 18 to 24 inches in diameter which can soak and hold a lot of water (in a toxic form) when it rains. This stored water helps not only in photosynthesis, but also protects the plant from the extreme heat. The heat absorbed by the plant during day is stored in the interior parts of the stems and the stored water does not allow this heat to spread upto the leaves due to low specific heat of water. At night this heat is released out which, in turn, prevents the plant from freezing in the chilled nights.

AMAZING ROOT SYSTEM OF A SAGUARO:

The root system of the plant is thinner considered to its size and weight. It has one tap root which grows only three feet. Two sets of radial roots spread out. One is thicker which is only about one foot deep and the other thinner set is as long as the plant itself. 

SPECIAL ADAPTATION:

RIBS ON THE STEM

A special adaptation of the plant is the pleated rib system on its stem. The ribs unfold its pleats and expands almost 25% of the original size of the plant while it is absorbing water, thus preventing the plant from bursting. When the water is used up, again the ribs fold up and shrink. This allows the Saguaro to be almost 90% water. Thus a matured Saguaro weighs more or less 6 tonnes.

FLOWERS OF SAGUARO

CO-EVOLUTION:

The Saguaro homes many bats, wasps, butterflies, ants and bees and also feed them with its nectar.

GILA WOODPECKER

The Gila Woodpecker has a mutual relationship with this cactus. The Gila Woodpecker holes the plant for nesting as it can not find any other suitable tall and woody plant for staying in the midst of the Sonoran Desert. Moreover the holes are made in the older and harder sections of the plant between the epidermis and the ribs without causing any harm to the cactus. Rather the Woodpecker can eat up the damaged parts of the plant or the other insects causing harm to the plant. In turn, the Saguaro creates a hard casing of scar tissues called callous, which detach the bird's nest from the rest part of the plant.

ILLEGAL POACHING OF SAGUARO

HUMAN INTERFERENCE:

In recent times, a black market has evolved in Arizona, where the poachers can easily make a few thousand dollars of the sale of Saguaro. however, it is still not endangered as the USA government has taken some positive steps in rescuing this rare species. There is a national park called Saguaro National Park for protecting the plant from poachers.