Biology - Paper 2

• Homeostasis is the maintenance of a constant internal environment and to keep your body functioning properly, we need to control our blood glucose levels, water levels and temperature.
• The brain is the control center and it sends signals to various parts of the body, such as the pancreas which is responsible for producing insulin, and the effectors which are muscles that do things like moving, for example shivering, and glands that are responsible for the production of hormones.
• The nervous system is incredibly complex and is overlaid on the spinal and muscular system, consisting of the brain, spinal cord, which together make up the central nervous system or CNS, all the neurons, receptors and effectors.
• When stimuli are picked up, the signal needs to travel from wherever it was picked up, such as your fingers, all the way up to the nervous system, sometimes just stopping at the spinal cord and then coming straight back again, this is a reflex.
• When a signal reaches the brain, it can be processed and then a decision made to move, this is known as a voluntary response.
• Wallace, who worked with Darwin, was important in the understanding of speciation due to geography.
• Mendel worked with sweet peas and was the precursor to discovering genes, which are units of information that inherit units of information.
• Microorganisms are alive and need certain temperatures, water levels, and oxygen levels to survive.
• Food security is how sure that we are going to have food on our table, which depends on our ability to produce food and import food from other countries.
• Decay and decomposition are the breaking down of organic matter, which generally happens by microorganisms.
• Evolutionary theory suggests that humans evolved from monkeys who evolved from primordial soup, which is not what the Bible says.
• Construction pyramids can be either pyramids of numbers or pyramids of biomass, each representing trophic levels.
• An alternative theory at the time of speciation due to geography was acquired characteristics, where if you dyed your hair blond during your lifetime, your baby would have blond hair.
• Gardeners can compost things to get rid of their unwanted items and take the nutrients back onto the garden.
• The nerve cells involved in this process are very long, with the cell body being incredibly long and able to send a fast electrical signal, however when transferring the signal from one nerve cell to another, things slow down a bit because they have to cross a synapse, this is a slow chemical signal.
• The male and female endocrine systems are different, with the pituitary gland located in the brain, thyroid in the neck, adrenal glands in the kidneys, pancreas behind the stomach, ovaries at hip level and testes below the penis.
• The testes produce testosterone which has the effects of growing muscles and making the balls and penis drop and grow larger, increasing the rate of hair growth.
• Estrogen is produced in the ovaries and is responsible for the maturation of eggs and the menstrual cycle.
• The pancreas produces insulin which is important for regulating blood glucose levels.
• The adrenal glands produce adrenalin which is important for our fight-or-flight response.
• The thyroid produces thyroxine which is important in regulating our metabolism.
• Eukaryotes are things that have nuclei.
• Animals need to adapt to their environment so they can survive.
• A species needs food, water, air, and sometimes a mate to survive.
• A community is the plants and animals that live there and depend on each other.
• Cacti are well-adapted to a desert environment because they have shallow roots, spines to prevent being eaten, and can store water in their leaves.
• The direction of the arrow in a food chain means eaten by.
• Biotic factors are living factors such as food, predators, and pathogens.
• The three-domain system divides everything in life into three groups: eukaryotes, bacteria, and archaea.
• An increase or reduction in the temperature could mean that an organism's food source is gone or an organism can't survive in that environment.
• An ecosystem is the animals, plants, everything living within a certain area.
• The development of new antibiotics is slow, partly because there are few places to look for them and partly because developing new drugs is expensive.
• All food chains start in the same place, with the sun providing energy and then things grow, mainly plants, which are then eaten by other things.
• Carl Linnaeus developed taxonomy, the study of grouping living things together.
• The size of the field needs to be estimated to work out how much area there is.
• Snow foxes are white so they blend in, have small ears to prevent heat loss, and have a very thick coat.
• Abiotic factors are non-living factors such as light intensity, temperature, water levels, pH, ion levels, wind, carbon dioxide levels, and oxygen levels.
• If you go into a hospital to have an operation, you will get swabbed for it to find out if you have an infection with antibiotic-resistant bacteria.
• To investigate what grows in a field, a quadrat, which is a meter square, can be thrown on the ground and plants can be counted randomly, moving it around the field to get a wide coverage.
• The plant population per area can be worked out and then multiplied up to cover the entire field.