Analysis of the walking chimps showed that chimps generally use large hip muscles and take short steps when walking upright. Humans tend to use smaller muscles, like those in their lower legs, and to take longer steps. This leads to improved energy efficiency. Not coincidentally, the chimps that took longer upright strides than their peers consumed less energy.

Chimp with large hip muscles

The experiment's results illustrate how energy expenditure contributed to human evolution. Early humans who adapted to expend less energy walking upright are represented in the fossil record. Fossils show that some ancient humans developed longer legs, different hip structures or thicker leg bones, consistent with modern-day humans. These adaptations made upright walking easier and lessened the amount of energy required to walk upright

Humans walking on two legs consume only a quarter of the energy that chimpanzees use while “knuckle-walking” on all fours, according to a new study.

Walking upright on two legs is a defining feature that makes us human

According to this theory, the energy saved by walking upright gave our ancient ancestors an evolutionary advantage over other apes by reducing the costs of foraging for food.

If they had a chance to grab a fistful of tasty treats before someone else snatched it, they stuffed the goodies into their mouths, and their hands, and ran to a safe haven on two feet. In fact, they were four times more likely to assume a human posture if the treats were particularly rare and the competition fierce.

Charles Darwin was an English naturalist. He studied variation in plants and animals during a five-year voyage around the world in the 19th century. Darwin later studied hundreds more animal and plant species. In 1858, after nearly 30 years of research, he proposed his theory of evolution by natural selection. He explained his ideas about evolution in a book On the Origin of Species, published in 1859

Charles Darwin is often cited as the greatest biologist in history. His most famous work, On the Origin of Species, explains the theory of evolution by natural selection, providing numerous supporting examples. Darwin believed that all of life on earth had descended from a common ancestor, whose offspring could vary slightly from the original. Successive generations of life took part in a struggle for existence in which the best adapted variations survived to seed new generations. Less well adapted variations became extinct.

Though he held fairly conventional beliefs in God, Darwin wasn't particularly keen on this new direction. But training to be a clergyman meant he had plenty of time to pursue his real passion: biology. He spent much of his time collecting beetles and walking on the Fens. He graduated in 1831 but before he could take a job as a cleric, the chance of a lifetime would come his way

Evolution and Inheritance

Evolution occurs when there is competition to survive (natural selection) and differences within a species caused by inheritance and mutations. Inheritance is when something is passed on to the next generation. Offspring are not identical to their parents and hence species change over time.

Evolution is a theory, an idea with lots of evidence. It explains why animals and plants are so good at surviving in their environments, the places where they live. What it means is that a  species changes over time and can even split in two new species.

The theory of evolution was developed by Charles Darwin back in 1859. He said that evolution worked through natural selection. Natural selection means that some individuals in a species are better at surviving than others and will have more children.

Rabbit live all over, and have dark fur. But in a place where it snows a lot, white fur would be an advantage. A white furred rabbit would be harder to see and is more likely to survive and have children. These children will inherit its mum or dad’s white fur. Eventually all the rabbits living in the cold place will have white fur.

Evolution also explains how one species can become two, like with the rabbits. We call this Speciation. The white rabbits are better fits where it snows but dark brown rabbits fit better where it snows less. With time, the different rabbits will become different species, both living in their own, separate environment.

Some animals are more closely related than others. The more closely related animals are, the more they look and act alike. Swans and geese look and act so similar because they are closely related. A sparrow looks very different to a swan but both still have beaks, feathers and can fly so are related but less closely than the swan is to the goose.

we look very different to a swan or a sparrow but we do have similarities. We both have two eyes, both have two legs, two arms (adapted to wings in a bird), one head, one heart, a nose and ears. We share all of these things and more with birds so, although we are very different, we are also related to birds.

This is called ‘survival of the fittest’ because animals which are best able to survive also fit better in their homes, like a white rabbit fits better in a cold country.

David Attenbough

After completing his degree in Natural Sciences at Cambridge University Sir David’s first job was in the Navy for two years from 1947.

When Sir David accepted the offer of his first job at the BBC in 1952 he like most Britons, didn’t own a television and had only ever watched one TV programme

He was Controller of BBC2 (1965-68), during which time he introduced colour television to Britain and commissioned an eclectic mix of programming, including Monty Python.

Sir David has said he doesn't love animals but is fascinated by them. However, he admits the only creatures he hates are rats.

Sir David Attenborough is believed to be one of the most travelled men in history. In order to film the Life of Birds series he had to travel over 256,000 miles. This is equivalent to going around the world 10 times!

In 1985 Sir David received his knighthood. He was previously honoured with a CBE (Commander of the British Empire) in 1974.

Sir David is the only person to have won a BAFTA in black and white, colour, HD and 3D.

Sir David has said he doesn't love animals but is fascinated by them. However, he admits the only creatures he hates are rats.

Sir David Attenborough is believed to be one of the most travelled men in history. In order to film the Life of Birds series he had to travel over 256,000 miles. This is equivalent to going around the world 10 times!

In 1985 Sir David received his knighthood. He was previously honoured with a CBE (Commander of the British Empire) in 1974.

Sir David is the only person to have won a BAFTA in black and white, colour, HD and 3D.

Inheritance

Each cell in the body contains 23 pairs of chromosomes. One chromosome from each pair is inherited from your mother and one is inherited from your father. The chromosomes contain the genes you inherit from your parents. whether the gene for that condition is dominant or recessive.

All or part of a person's estate/assets that is given to an heir once the person is deceased. An inheritance is typically a cash endowment given to younger heirs of the deceased, however any assets can be considered as part of an inheritance, such as stock certificates or real estate. If a will is not in place at the time of death, determining the rightful heirs of the deceased's estate becomes a much more complicated matter.

Inheritance is why you look similar to you mum or dad. People’s bodies have characteristics, like the shape of their nose or the colour of their eyes, and parents pass on these characteristics to their children, this is inheritance.

Inheritance

We are made of cells like a building is made of bricks. Our cells are told what to do by DNA. DNA is the boss and tells the cells how to make a human body. All of us are made up of DNA from both our mum and dads so we inherit orders on how to build a body from both of them that is why we have characteristics from both our parents.

People look like people. Every person is unique but they have far more in common than they are different. This is because we are all related and we have all inherited characteristics from our ancestors.

We share an ancestor with a monkey but that ancestor lived a very long time ago so we look more different from monkeys. Even so, people and monkeys still have a lot in common. We both have two legs, two eyes, two hands and many other things. generally, the closer related we are to another species, the more like them we look.

Most commonly, traits are influenced by multiple genes and the environment. So for most traits, patterns of inheritance are complex and unpredictable. For instance, when a sexually reproducing organism inherits a defective or "broken" allele that codes for a non-functional protein, the second copy can often make up for the loss. This type of interplay between alleles, especially when traits are influenced by multiple genes, makes predicting inheritance difficult, if not impossible.

A small number of traits are influenced primarily by a single gene. Traits influenced mainly by one gene usually have predictable patterns of inheritance. However, most of the time even supposed "single-gene" traits are influenced by multiple genes, as in the case of eye color. And often times, a single gene can influence multiple traits. For example, some genes involved in eye color also influence hair and skin colour.

Evolution

Darwin's theory of evolution explains how species of living things have changed over geological time. Scientists believe this is the reason why all living things on Earth exist today. Many species have become extinct in the past and the extinction of species continues to happen.

Evolution

The basic idea behind the theory of evolution is that all the different species have developed over time from simple life forms. These simple life forms first developed more than three billion years ago - the Earth is about 4.5 billion years old.

This timeline below shows some of the key events in the evolution of life forms on Earth, from the first bacteria to the first modern humans

When environments change, some species survive or evolve. However, some species become extinct. The fossil record shows that many species have become extinct since life on Earth began

The idea of evolution is a simple one. Things change. Right now we're just talking about the word, not the philosophical idea. The process of cars changing over the past 100 years can be thought of as an evolution in engineering. When an organism changes over many generations, it might be better suited to live, or more likely to die. To describe what happens, scientists have a few terms.

The basic idea behind the theory of evolution is that all the different species have evolved from simple life forms. These simple life forms first developed more than 3 billion years ago (the Earth is about 4.5 billion years old). The timeline below shows some of the key events in the evolution of life on Earth, from the first bacteria to the first modern humans.