FRACTS! Archives - Page 2 of 2 -

August 15, 2013May 11, 2016

Fracts #5 – Do all frogs lay their eggs in water ?

Most amphibians lay their eggs in fresh water or on land, but others are viviparous, meaning the babies grow within the mother’s body and are born live.

Frogs are among the most prolific breeders and can lay anywhere from 1 egg to 25,000, while salamanders lay a few dozen. Some frogs and salamanders defend their eggs and may carry eggs or tadpoles on their backs. For species which practice internal fertilization, females guard the eggs. For eggs that are externally fertilized, males guard and defend the eggs within their territory. In fact, paternal care is most common in fish and amphibians and not mammals!

Main reasons why frogs lay eggs in water

Moisture: Frog eggs require moisture or they will dry up and die. Frogs lay their eggs coated in a jelly-like glycoprotein. The jelly helps keep the eggs from drying out, but must maintain contact with a moisture source. Frogs can lay their eggs on pond vegetation, floating on the water’s surface, or on the pond bottom. Many frogs lay their eggs in vernal pools, which are large, temporary puddles formed by spring rains.
Tadpoles: Adult frogs can survive on land and in water, but tadpoles can survive in water only. They have gills for underwater breathing and tails for swimming. If tadpoles hatched on land, they would not be able to breath or move around.
Protection: Bird eggs have hard shells that protect the embryos from trauma. Because frog eggs are soft and moist, they require cushioning to protect the developing tadpoles. Water provides this cushioning.
Guarding: A few frog species, such as Darwin’s Frog, watch over their eggs and guard them from predators. Darwin’s Frog is primarily aquatic and would not be able to guard eggs laid on land away from the water.

Case study: Darwin’s Frog

Darwin’s frogs have a rather odd and unique way of protecting their young from predators

Male Darwin’s frogs engage in a behavior called mouth-brooding, where they take their own fertilized eggs into their mouth just before they hatch. They’re not eating them. Instead they store them in the vocal sacs that they otherwise use to make mating calls to attract females. There the tadpoles hatch and develop in complete safety from fish, dragonfly larvae and all the other aquatic predators that normally threaten them (unless of course daddy gets eaten himself), surviving on the nutrients of the yolk that their mother’s egg provided them.

When the tadpoles fully complete metamorphosis inside their father’s vocal sac, he opens his mouth and “barfs” them out into the world, miniature versions of himself ready to fend for themselves.

Watch this video to see the tadpoles writhing underneath the skin of these daddy frogs just before they reach full development and he barfs them out to begin life on their own. You can’t help but watch this and be fascinated at how odd and wonderful the natural world is!

[youtube=http://www.youtube.com/watch?feature=player_embedded&v=HCxv6AbBwJI]

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Glossary
Viviparous – an animal that gives birth to live young. Contrast with Oviparous and Ovoviviparous
Metamorphosis – a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal’s body structure through cell growth and differentiation

Reference
http://www.sciencedaily.com/releases/2012/09/120910142632.htm
http://www.worldanimalfoundation.net/f/TreeFrog.pdf
http://animals.pawnation.com/main-reason-frogs-lay-eggs-water-4238.html
http://blogs.discovery.com/animal_oddities/2011/08/frog-daddy-barfs-out-babies.html

July 29, 2013

Fracts #4 – What a frog might say

Do you know that for some species of frogs, only the males sing?

Every different species of frog makes it’s own special sound and it is only the male frog that can croak. They have a small sac in their throats that vibrates the air as they slowly let it out.

Other types of frogs appear to have both male and female calls.

Large frogs have deep voices, meaning they call at a low frequency. For example, the Male American Bullfrog’s call is reminiscent of the roar of a bull, which gives the frog its common name.

Small frogs sing in high chirps, meaning they call at a high frequency.

Cold frogs repeat their calls at a slower rate because the muscles controlling the sounds slow down!

Why do frogs sing? Well…it’s actually for a variety of reasons!

Sometimes, frogs sing when they are trying to attract a mate. “HEY! Baby!”
Sometimes, frogs sing to mark their territory. “This is MY Lilypad!”
Sometimes, frogs sing becasue they know the weather is going to change. “Rain!!!”
Sometimes, frogs squeek when they are frightened or hurt. “Ouch! Eek!”

A bonus joke for today’s Fracts,

July 23, 2013May 11, 2016

Fracts #3 – The effects of Globalisation on frogs

Globalisation is an intensively debated topic and encompasses many different areas. For this article, we shall define globalisation as the intensification of trade within nations, specifically the import and export of frogs. Frogs can be found in almost every corner of the Earth and this had allowed them to diversify into 4000 types including toads. Each species of frog has it’s own niche that enables them to thrive in their environment, hence making them the best bioindicators to study the ecosystem.

Quoted by Charles Darwin,

“In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.”

For example, tadpoles keep waterways clean by feeding on algae. Adult frogs eat large quantities of insects, including disease vectors that can transmit fatal illnesses to humans (i.e. mosquitoes/malaria). Frogs also serve as an important food source to a diverse array of predators, including dragonflies, fish, snakes, birds, beetles, centipedes and even monkeys.

Thus, a decrease in frog populations disturbs an intricate food web, and results in negative impacts that cascade through the ecosystem.

In our previous Fracts #2, we have discussed how Scientists around the world had been using South African Clawed Frogs for research as well as conducting pregnancy test. In Fracts #3, we will be exploring the implications of such activity.

Yes, frogs may have adapted well to its environment. However, the introduction of foreign species not only increase competition of getting food and space, it also introduces new diseases and other threats (as introduced in our Fracts #1 – The Amphibian Crisis)

A case study

Inadvertently introduced to Australia when the African clawed frog was imported for use in a pregnancy test, chytrid fungus is a global problem threatening all species of frogs, including Australia’s critically endangered southern corroboree frog and the stuttering frog.

A water-borne disease, chytrid fungus attacks the keratin in the skin around the animal’s feet and under the mouth. The theory is that this effects the iron balance in the body, which has neurological effects. Infected frogs become lethargic and unable to eat but probably die

There is currently no treatment or effective infection control for the fungus in the wild.

In conclusion, the balance of the ecosystem is fragile in such a way that any slight change/introduction of an animal population may cause irreversible damage to a habitat.

The ability of humans to manipulate nature is a disadvantage but it is also a great asset. Therefore, each and everyone of us can make a difference by changing our perception of the world and that we are not living alone on this one and only Blue Planet called Earth.

Dictionary:
Niche – the position or function of an organism in a community of plants and animals.

Reference:
http://www.theage.com.au/national/ancient-fungus-has-worlds-frogs-in-its-deadly-grip-20130604-2nodj.html
http://www.frog-life-cycle.com/frog-myths.html
http://www.savethefrogs.com/why-frogs/

July 16, 2013May 11, 2016

Fracts #2 – A frog can tell you’re pregnant?

Before the modern development of pregnancy test kits, what is one of the ways that can tell you’re pregnant?

You guessed it…

FROGS!

For 20 years, 1930s to 1950s, Scientists around the world had been using South African Clawed Frogs for research as well as conducting pregnancy test.

Wait a second, how do you use frog to test for a baby?

Once urine sample is collected, it is then injected into the frog’s dorsal lymph sac in the morning and by the end of the day, results can be concluded. A dose of a pregnant woman’s pee will cause a female South African Clawed Frog to lay effs within eight to 12 hours. The test also works on male frogs, which produce sperm in response to the injection.

Why does it work?

It works because a pregnant woman’s urine contains a hormone called human chorionic gonadotropin, or hCG. This is exactly how most modern pregnancy test rely on the detection of hCG using other means like antibodies after 1960s.

In 1930, a scientist based in Cape Town, South Africa, named Lancelot Hogben reported that he could use ox hormones to control ovulation in a local frog species—Xenopus laevis. His discovery was important for two reasons: First, it provided embryologists with a frog that could produce eggs year-round. Second, it provided doctors with a new animal for pregnancy testing. By 1933, doctors were using the “Hogben test” to detect hCG in urine.

The Hogben test was both rapid and reliable, and it spread quickly throughout Europe and the United States over the next two decades. Scientists were able to rear the clawed frogs in captivity, but it was easier to import them from Africa in large numbers. Either way, the reliance on live animals posed problems for the big testing centers. Even a facility with several thousand frogs could be shut down by a virulent disease outbreak. The development of new testing methods in the 1960s made the Hogben test obsolete.

Reference:
http://d3rmmzlisdjvlb.cloudfront.net/wp-content/uploads/2012/09/shutterstock_49901470.jpg
http://www.slate.com/articles/news_and_politics/explainer/2006/01/the_amphibian_pregnancy_test.html
http://science.howstuffworks.com/zoology/reptiles-amphibians/frog6.htm

July 6, 2013May 11, 2016

Fracts #1 – The Amphibian Crisis

So let’s begin with the birth of our first Fracts: Fract #1

Do you know that the earliest Frogs were known to have lived as early as 265 million years ago (Permian era) compared to us modern humans (Homo Sapiens) 150 000 years old.

Having to live and survive through mass extinctions, frogs have earned itself as one of the most resilient and adaptable creatures on Earth. Perhaps due to the fact that Frogs are amphibians, they can live on both land water, allows them to have an alternative hideout away from natural disasters. Today, there are nearly 4000 types of frogs, including toads, and they can be found on almost every continent (in green) except Antartica where the climate is very cold all year round. .

However, frogs (and other amphibians) today may not be able to survive the next mass extinction that the Herpetologists call it, The Amphibian Crisis. Watch this video clip to find out more!

[youtube=http://www.youtube.com/watch?v=6FBn0x6XwEQ]

Therefore, what are your views on this crisis? Are we humans responsible? What you readers reckon all of us can do our part to save their existence on this Earth?

If you would like to share your opinions on how we can save our frog friends, do feel free to reply in the comment box.

July 2, 2013

The birth of Fracts

Knowledge is power. Information is liberating. Education is the premise of progress, in every society, in every family.

– Kofi Annan

Just like how our tour programmes are designed to cater to different age groups, learning neither only happen in schools nor stop when you graduate from it! Learning happens everywhere and is a life long process!

Very well then, can anyone guess what is Fracts? (Hint: A combination of what we do here in the farm and a source of learning)

The answer: Frog + Facts = Fracts (Please highlight on the blank space to reveal the answer)

Congratulations if you have guessed it right! Fun isn’t it?

Here in Jurong Frog Farm, we believe that education in a farm setting plays a crucial role in society. Education, apart from other things, makes up society. From reference to this article, one of the reasons why we behave and decide the way we do is due to ‘framing and anchoring’. In other words, every decision depends on information. For example, frogs are amphibians and without water in their natural habitat, they will die. It is this kind of information that tells us that we must conserve mother nature (by having the habit of 3 Rs) as much as we can so that we do not destroy the natural habitat of frogs and other animals.

Hence, by sharing knowledge about the wonderful history and life of frogs, as well as its threats, we can play a part to make informed decisions before behaving in a certain way, especially towards our dear friend, the Frogs.

(CROAK CROACK!) – “that’s right!” in frog language.

Basically, Fracts (a singular noun) is a weekly episode of frog facts combined with occasional humour and thought provoking articles that will make you muse and ponder.

So, stay tuned for Fracts #1!

Note:
3 Rs: Reduce, Reuse, Recycle