It is a change in the environment which is detected by the receptors
What does the receptors do in the nervous system response
Information from receptors passes along cells (neurones) to the CNS as electrical impulses
What does the coordinator do in the nervous system response
The CNS coordinates the body’s response to the stimulus
What does the effector do in the nervous system response
They bring about a response, such as glands secreting hormones or muscles contracting
What does the response do in the nervous system response
The body responds to the stimulus
What are factors affecting reaction time
Tiredness, Distractions, Caffeine, Alcohol
What is homeostasis
It is the regulation of internal conditions (of a cell or whole organism) in response to internal or external changes, to maintain optimum conditions for functioning
What is maintained for optimum function
Blood glucose concentration
Body temperature
Water levels
What 2 responses are involved of homeostasis
Nervous response and chemical response
What are all the control systems involved in homeostasis
-Receptor cells, which detect stimuli
-Coordination centres(like the brain, spinal cord and pancreas)which receive and process information from the receptors
-Effectors(muscles or glands), which produce responses to restore optimum conditions
What is a reflex arc
They are reflex actions of the nervous system that are automatic and rapid-they do not involve the conscious part of the brain
Why are reflex actions importation
they are important for survival because they prevent damage to the body
What are neurones
They carry electrical impulses around the body - relay neurones connect sensory neurones to motor neurones
What are synapses
they are gaps between neurones, which allow electrical impulses in the nervous system to cross between neurones
What is variation
The differences in the characteristics of individuals in a population
What can be the difference for variation
The genes they have inherited e.g. eye colour
The environment they grew up in e.g. language
A combination of gene and environment
What is a mutation
It is a change in a DNA sequence
What is selective breeding
It is the process by which humans breed plants and animals for particular genetic characteristics
What are the processes of selective breeding
1.Choose parents with the desired characteristics from a mixed population
2.Breed them together
3.Choose offspring with the desired characteristics and breed them together
4.Continue over many generations until all offspring show the desired characteristics
What are the benefits of selective breeding
Disease resistant in food crops
animals produce more milk or meat
domestic dogs with gentle nature
larger or unusually flowers
Disadvantages of selective breeding
Can lead to inbreeding, where some breeds are particularly prone to inherited defects or disease
Reduces variation, meaning all members of a species could be susceptible to certain diseases
What is Genetic engineering
It is a process that involves changing the genome of an organism by introducing a gene from another organism to produce a desired characteristic
What are the benefits of Genetic engineering
-Potential to overcome some inherited human disease
-can lead to higher value of crops as GM crops have a bigger yields than normal
-crops can be engineered to be resistant to herbicides
What are the risks of Genetic engineering
-Genes from GM plants and animals may spread to other wildlife, which could have devastating effects on an ecosystem
-Potential negative impacts on population of wild flowers and insects
-Ethical concerns, like people could manipulate the genes of get used for certain characteristics
-Health concerns as eating crops that are GM have not been fully explored