Looking at Physical Development it can be seen if the process of genes and environment operating together influence development. As the environment is constantly changing humankind needs to have changeable characteristics, some of which are physical, this is known as "Developmental Plasticity". Piaget studied water snails and found that shape of the snails shell varied depending on its habitat. Pond snails had longer shells than lake snails who had shorter shells to suit the water turbulence. Suggesting that cells have the properties to change and become "self-organising", cells can change the way they are developing in response to environmental stimuli. It is argued that genes can be switched "on" or "off" in response to this environmental stimuli and can alter the characteristics they produce.
"Piaget called this process "Epigenetic Development", Epigenetic information is constantly being acquired throughout development, giving the environment an active role in influencing development. The environment is shaping information in our genes and changing our physical development. Humankind standing on two legs and walking was a response to environmental changes. This has had a significant effect on our genetic makeup from the shape of our pelvis to the size of our skull.
Epigenetic systems can only change things during the period of maturation and once a characteristic is adapted it can not change back. Richardson, 1994, argues in relation to child development this would mean that once a child has learnt a particular behaviour this can not be changed or removed. Richardson argues because of our changing environment humankind need genetic characteristics which are changeable and can adapt through out a lifetime. We are constantly learning new things, and adapt our behaviour to what we have learnt.
Learning is one of the processes which require our behaviour patterns to adapt through our lifetime. Life long developmental plasticity is a form of epigenetic development more suitable to child development as aspects such as language, behaviour adapt to suit our environment. Other theories exist which explain the importance of genes and the environment in child development.
Belief that all human development can be explained by genetic make up is called genetic determination. This view sees behaviour as having end points and of humankind having little control over their development. The Genetic theories are rigid or Canalised systems.
Plotkin and Odling-Smee, 1979, argue genetic determination needs environment to remain constant for many years in order for advantages of adaptation and natural selection to emerge. This is unlikely to happen in our ever changing environment, humankind can change its own environment. This can be seen by the creation of nuclear weapons, and the cutting down of rainforests.
By studying twins and heritability it is possible to see to what extent genes influence our development. Heritability is what geneticists use to measure genetic differences, similarities are rated between 0 and 1. The higher the score the...