Why do bones remain for centuries after a person dies?

Why do bones remain for centuries after a person dies?

Bones are made of two main materials: Calcium salts make bones hard, and collagen fibres make them strong but also a bit flexible. After death the collagen rots away, leaving just the durable hard parts behind. In life, the bones of a person's skeleton support the body and protect its internal organs.

FAST FACTS

Mammals

• There are nearly 4,500 species.

• Mammals are very diverse and include plant - eaters,insect eaters, meat-eaters,   and omnivores (who eat everything).

• Mammals are found on the land, in water,and in the air.

•  There are five species of egg-laying monotremes, such as echidnas.

•  There are 292 species of pouched marsupials, such as the koala.

•  The remainder are placental mammals (young develop inside their mother's             uterus),such as hyenas and humans.

•  Nearly half of all mammal species are rodents.

•  Around one-fifth of all mammal species are bats.

Diary of a duck egg..

Diary of a duck egg!

Day 1

Just laid - I'm an embryo resting on a yolk food store.

Day 12

It's safe and warm in this hard shell, and at last I'm beginning to feel like a bird.

Day 20

I've been growing fast and things are a cramped in here - I'm planning to break out, but I can't find the door.

Day 21 morning

In desperation, I have begun to bash my way out with a toothy bit on my beak - I can see the light at last.

Day 21 afternoon

I'm free! My feathers have dried out, and I've found my legs and am running around. I am starting to feel a bit peckish, so will  start looking for food.

What are arachnids?

What are arachnids?

This is the group of invertebrates (animals without backbones) that includes spiders, scorpions, harvestmen, mites, and ticks. There are about 65,000 species of arachnid, half of which are spiders.

                            

 Record Breaker

A spider web in Lake Tawakoni State Park in Texas, USA, covered 180 sq m (1,940 sq ft) of trees and bushes. What was once a white web web soon turned dark when hundreds of mosquitoes got caught in it.

How do mushrooms grow so fast?

How do mushrooms grow so fast?

Mushrooms belongs to a unique group of living things called fungi. They consist of a network of hair-like threads called hyphae, which spread unseen through soil.When the conditions are right, hyphae push upwards out of the soil with incredible speed to form a mushroom.

Are bacteria important?

Are bacteria important?

Bacteria are the most plentiful living organisms on the planet. They are also the smallest, each consisting of a simple, single cell. A few types of bacteria, often called germs, cause disease in humans. But most bacteria are harmless,and some are very useful, including those used in making foods and drugs.


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Dienocoous radiodurans must be the most resilient bacteria.It can withstand blistering heat, bitter cold, drying out, high radiation levels, and being doused in strong acids.

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Who ruled the world after the dinos died out?

Who ruled the world after the dinos died out?

Sixty-five million years ago, a mass extinction wiped out the dinosaurs.Mammals had been around since the Jurassic Period. Living alongside the dominant dinosaurs, they were just a small group of tiny, rodent-like creatures. When the dinos died out, so did many of the mammals,but the survivors evolved to become the most successful type of animals around.