Flea life cycle: Characteristics, Stages & Metamorphosis

Ans: Metamorphosis is a biological process whereby, through various cell growth and division, an animal transforms into a specific physical structure. The life cycle of fleas goes through complete metamorphosis, so it is called holometabolous.

Ans: To differentiate a female and a male flea, the structure of and placement of their eyes can be considered as a parameter. Both eyes of a male flea are close to each other. On the other hand, female fleas have wide eyes.

Ans: Adult fleas are about 3 mm long. It has a long, flattened body shape, which helps to move through the host's body. During the pre-mature state of adult fleas, they are much darker or dark brown in color. They have eyes and legs. But, fleas don’t have wings in any of their life stages. Gradually, these fleas turn into larger fleas with lighter colour in appearance.

Ans: Fleas are mostly fond of dirty places with high humidity. They either prefer wounds in a host’s body or unhygienic conditions to live in. Due to living in places like these and completing their nutrition with debris and blood, fleas can spread diseases. The ability to spread diseases by fleas is called "flea infestation."

Ans: The four stages of a flea's life cycle are-

1. Eggs
2. Larvae
3. Pupa
4. Adult stage

Ans: Preventing flea infestation is quite easy and isn’t uncommon at all. To prevent flea infestation, routinely clean waterlogged plant pots and surroundings. Cleaning pets' houses with anti-insect shampoo is necessary. To clean your wounds, use antiseptic creams and lotions. These simple steps of maintaining hygiene is enough to prevent flea infestation.

Ans: Larvae and pupae are the middle stages of a flea’s life cycle. These 2 stages take a total of approx. one month to transform into an adult flea. The stages are as follows-

1. Larvae: A larva takes 18–20 days to become a pupa. In their larvae stage, fleas come out of eggs with a 3 mm long whitish appearance. It has no legs. Larvae avoid being in places with light because they are blind. It needs humidity of more than 45% and a temperature of less than 90 degrees Celsius to survive. Consuming dry skin, pre-digested blood from adult fleas and dead insects, wasted food particles helps larvae to be alive.
2. Pupa: Pupa stays within their cocoon. Cocoon of a Pupa is dark in colour. The darker the cocoon, the quick pupa becomes an adult flea. With a host's lair Pupa gets transformed into an adult flea. Pupa needs vibration, heat and temperature etc. to break their cocoon with their head and it comes out of it as adult fleas. 4-5 days of adverse conditions complete the transformation of pupa to adult flea.

Ans: The diploid sporophyte is represented by a dominant, independent, photosynthetic, vascular plant body. It alternates with multicellular, saprophytic/autotrophic, independent but short-lived haploid gametophyte. called prothallus. Such a pattern is known as haplo-diplontic life cycle. All pteridophytes exhibit this pattern.

These gametophytes require cool, damp, shady places to grow. Because of this specific restricted requirement and the need for water for fertilisation, the spread of living pteridophytes is limited and restricted to narrow geographical regions. The gametophytes (prothallus) bear male and female sex organs ‘ called antheridia and archegonia, respectively.

Water is required for the transfer of antherozoids—the male gametes released from the antheridia to the mouth of the archegonium. Fusion of male gamete with the egg present in the archegonium results in the foundation of the zygote. Zygote thereafter produces a multicellular well-differentiated sporophyte which is the dominant phase of the pteridophytes.

Ans: Male and female gametophytes of pteridophytes are free-living while in gymnosperms male and female gametophytes do not have free-living existence. They remain within the sporangia retained on sporophytes.

Ans: The life cycles of endoparasites are more complex because of their extreme specialisation. Their morphological and anatomical features are greatly simplified while emphasizing their reproductive potential.

In accordance with their lifestyle parasites evolve special adaptations such as:

1. Loss of unnecessary sense organs.
2. Loss of digestive system.
3. High reproductive capacity.
4. Presence of adhesive organs or suckers to cling on to the host.

Ans: The presence or absence of a cavity between the body wall and the gut wall is very important in classification. The body cavity, which is lined by mesoderm, is called coelom. Animals possessing coelom are called coelomates, e.g., annelids, molluscs, arthropods, echinoderms, hemichordates and chordates. In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates, e.g., aschelminthes. The animals in which the body cavity is absent are called acoelomates, e.g., platyhelminthes

Platyhelminthes

Ans: (i) Diploblastic: Animals in which the cells are arranged in two embryonic layers, external ectoderm and internal endoderm, are called diploblastic animals, e.g. Porifers, coelenterates and ctenophores.

(ii) Triploblastic: Those animals in which the developing embryo has a third germinal layer, mesoderm, in between the ectoderm and endoderm, are called triploblastic animals. E.g.: Platyhelminthes to Chordates.