What do frog eggs look like? Frog eggs are different from other animal’s eggs. They appear as the transparent small gel like globules having black spot in the middle. Eggs of frog are stuck with each other, collectively known as “frogspawn”.
FROG - AN AMPHIBIAN
Frog is a member of carnivorous group. Carnivora is an order of placental mammals that eat flesh of other animals; these include bears, cats, wolves, lion, dogs, raccoons and many more. Frogs belong to phylum Chordata, having an order “Anura”, which is an Ancient Greek word, which means “without tail”. Their skin comprises of different colors from well-camouflaged dappled brown, green, grey to vivid patterns of bright yellow, red and black, this shows their toxicity. Skin of frogs is semi permeable, which makes their bodies dehydrated, so they mostly live in moist places or have some special adaptations to heal with the dry habitats.
Frogs have no tail, only larvae possess tail. They don’t have neck and oesophagus, no claws. They have large bulky eyes, webbed toes, loose slimy skin, a short vertebral column, with no more than 10 free vertebrae and fused tailbone (coccyx or urostyle). Frog is a cold blooded animal. Frogs have three respiratory mechanisms which they use to exchange gases with the surroundings; these are, through skin, through the lining of the mouth and through the lungs.
Frog is an amphibian. Amphibians are ectothermic, cold blooded animals, belong to the phylum Chordata. The word amphibian is derived from the Greek word Amphibios which means “living a double life”. They have the ability to use both aquatic and terrestrial habitat. Amphibians have dual life which means they spend starting phase of their lives in water and when they grow up to the adult they move to the land. In their early period, they respire through gills and when they start living on land their gills modify into lungs or some use skin as their respiratory surface. The three orders of amphibians are Anura (e.g. frogs and toads), Urodela (salamanders are the example) and Apoda (e.g. the caecilians). The number of known amphibians is about 8000, of which nearly 90% are frogs. The smallest amphibian in the world is a frog with a length 7.7 mm, while the largest living amphibian is a giant salamander having a length of 1.8 m which makes about 5 ft 11 in. Other than frogs, toads, salamanders, microsauria, amphiuma, caudata, etc, are the examples of amphibians.
SUMMARY: Frogs are amphibian having dual nature of life. Some frogs are toxic while others are not. Most of the amphibians are different species of frogs. Their skin varies of different colors.
Metamorphosis is a biological process in which animals rapidly alter physical change after birth or hatching. Animals that experience metamorphosis process are: insects, fish, most of the amphibians, mollusks, etc. Metamorphosis may be complete or incomplete.
Complete metamorphosis, also known as “holometabolism” is the form of development which includes four stages, which are egg, larva, pupa and adult or imago. In each stage, animal looks different from the previous one. The life cycle of ants, bees, butterflies, frogs, beetles, wasps, etc are the example of complete metamorphosis.
Incomplete metamorphosis, also called “hemimetabolism” or “hemimetaboly”, is the form of development which follows three different stages, which are egg, nymph and adult or imago. There is no pupal stage in incomplete metamorphosis. Insects like lice, grasshoppers, bugs, crickets, cockroaches, etc undergo incomplete metamorphosis.
LIFE CYCLE OF FROG
Life cycle is a course of events which refers to the changes that an individual organism undergoes during its life time. A life cycle repeats itself for each new generation of life. The 5 stages of a life cycle includes; development, introduction, growth, maturity and decline/ death. In each stage, an organism change itself. During the life cycle of frog, prolactin and thyroxin hormones control transformation of egg to larva to adult. Starting from the very first stage which is “breeding”:
The breeding period of frog usually starts during the spring in temperate climates and during the rainy season in tropical climate. Frogs assemble at a pond, lake or stream to breed. When the male frog is ready to breed, it arrives at the breeding site and use loud croaking calls to attract female frog. During breeding, male frog grips female frog round the body. The female frog releases the eggs in the water and male frog covers them with sperm. This type of fertilization is external.
Now, the following is the process of how the eggs develop to the adult frog:
The female frog lays a huge number of eggs, around 4,000 at a time. These eggs are clumped together in groupings known as “frogspawn”. The embryos are surrounded by the layers of gelatinous material which provides protection and support. This gel like material also helps in the passage of carbon dioxide, oxygen and ammonia. The black and the dark brown spots absorb the warmth of the sun, which speeds up the development of larvae. As the eggs mature, the yolk in each egg splits into cells and begins to develop into the larvae. Within one to three weeks, eggs break down and tiny larvae come out.
The larva that pops out from egg is known as tadpole. They have a long, vertically flattened tail; tadpoles look more like a fish than a frog. They are totally aquatic, have cartilaginous skeleton and they respire through gills. Their tails are stiffened by a notochord. Soon, the lungs start to develop and are used as an accessory organ for breathing. They also start to grow two hind legs. Tadpoles are mostly herbivorous; they fulfill their nutritional requirement by feeding on algae, while some are carnivorous and they eat smaller tadpoles, insects and tiny fish. Their body elongate, front limbs develop and tails shrink. This is a short period of development which lasts in a week.
METAMORPHOSIS DURING LIFE CYCLE
After tadpole stage, frog undergoes metamorphosis process, in which it makes a sudden change into the adult form. The process starts by the release of thyroxine hormone and ends within 24 hours. During this period, frog makes numerous changes in itself. Lungs are developed and gills are vanished. The lower jaw developed into the big mandible of carnivorous adult. Some associated glands are formed. Skin becomes thicker and skin glands are formed. The long gut of herbivorous tadpole is replaced by the short gut of a predator. Frogs locomote with the help of limbs.
YOUNG FROG (FROGLET)
When the frog is young, it uses the nutrients from its tail as food to survive, until the tail is completely gone. When a little stub of its tail left, the young frog hops right out of the water onto the dry land. The frog is very small.
Once the tail is almost vanished, it is known as adult frog. Frogs prey on the invertebrates like worms, small snails, and arthropods, a few of the larger ones may also eat young frogs. Adult frogs are ready to repeat the life cycle, lay eggs and more tadpoles hatch. Frogs are primary predators and thus eaten by the secondary predators like snake, seal, lion, foxes, etc. These animals are the important part of food web. A frog lives for an average age of 7 to 10 years.
ABSTRACT: For development, frogs undergo complete metamorphosis process. The life cycle of frog include four stages eggs, larva which is a tadpole, froglet (young frog) and an adult frog.
WHAT DOES FROG EGG LOOK LIKE?
The shape and size of egg varies from the different species of frogs. Female frog lays numerous eggs at a time; this bunch of eggs is known as “frogspawn”. Black spot is covered by the gel like material which protects the embryo. The eggs are drowned at the bottom of the pond. In some species like Northern red-legged frog and wood frog, symbiotic unicellular green algae are present in the gel like material. This provides the larva extra oxygen through the process of photosynthesis. 80% of frogs’ eggs are made up of water.
FREQUENTLY ASKED QUESTIONS
What is the oldest frog in the World?
The oldest frog in the World was found in New Zealand. The frog was found to be 37 years old. The Maud Island Frog was nicknamed “Wellington” by researchers.
When do frogs hibernate?
Terrestrial frogs burry themselves inside mud, while aquatic frogs spend their hibernation period on the bottom of ponds and lakes. The hibernation period held during winter, most often January onwards. Hibernation happens because they become less active as the temperature reduces, so they find some place to rest during low temperature.
Where do frog lay eggs?
External fertilization takes place in frogs. Female frog lays eggs in water i.e. in lakes or ponds. Female frog mostly lays eggs under the leaves above water. Eggs hatch and tadpoles fall into the water where they can develop into young frogs (froglet).
It is concluded that, frogs’ eggs appear in a large cluster form. Black or dark brown spots are covered by the gelatinous mass. Frogs live a dual life, in early stages of life they live in water and respire through gills, while in the adult form they move out to the dry land and exchange of air takes place through lungs. Their life cycle undergoes holometabolism or complete metamorphosis.