Animal Survival Standard Grade Biology
Give 5 reasons why the body needs food.
The Need for Food
The 3 main types of food are carbohydrate, fat and protein. State the chemical elements present in each. What are the sub-units? What are the uses of these foods in the body?
Types of Food
Define the term digestion.
The Need for Digestion Digestion is the breakdown of large, insoluble particles into small, soluble molecules so that they can be absorbed into the blood stream. Whilst food is in the gut it is technically outside the body.
What are the 2 main ways food is broken down? State the 5 main types of teeth and give their function. Compare the dentition of a carnivore with that of a herbivore.
Teeth Teeth start the mechanical breakdown of food, saliva starts the chemical breakdown. You can tell what an animal eats from its teeth Omnivore Teeth
Carnivore Teeth
Herbivore Teeth
Label the different parts of the digestive system.
State the function of the different parts of the digestive system.
Describe the process of peristalsis.
How Food Moves through the Gut (peristalsis) Peristalsis is aided if the diet contains a lot of roughage or fibre which humans cannot digest Foods rich in fibre include fruit, vegetables and whole grains
Why are enzymes said to be specific? Where is bile made and stored? What does the term emulsification mean?
Digestive Enzymes Promote the chemical breakdown of food as it passes through the gut. Enzymes are specific, different enzymes break down different food groups Complete digestion of a meal requires many enzymes Bile is made in the liver and stored in the gall bladder Bile is not an enzyme It breaks large drops of fat into smaller drops and allows lipase to act on the larger surface area. It has no chemical effect on the fat.
Give an example of the enzyme and product for the following substrates: Protein Carbohydrate Fats
The Main Digestive Enzymes Enzyme Group Enzyme Substrate Product Carbohydrases Salivary amylase Carbohydrate maltose, Maltase maltose glucose Peptides, Proteases Pepsin Protein amino acids (needs HCl) ) Fatty acids Lipases Lipase Fats + glycerol
What are carbohydrates, fats and proteins broken down into?
Carbohydrate and Protein Digestion
Give 3 ways the structure of the small intestine is suited to its function. Explain. What is the purpose of the lacteal in the villi?
Absorption in the Small Intestine
Structure of a Villus
Explain the role of the large intestine.
The Large Intestine By the time the contents of the gut reach here all the useful products of digestion have been absorbed This is stored in the rectum and eventually leaves the body through the anus Large intestine absorbs excess water leaving a semisolid mass of undigested material called faeces
Reproduction All living things need to reproduce in order to produce young to replace the members of the species when they die Sexual reproduction involves two parents
State how the sperm and egg cell are suited to their function.
The Egg and the Sperm Sperm Egg Very small Swim using tail No food store Larger (See picture ) Cannot move by themselves, moved by cilia in oviduct Have a food store Millions made and released Much fewer made and 1 released each month
The Male Sex Organs
The Male Sex Organs
The Female Sex Organs
The Female Sex Organs
Explain the process of internal fertilisation. What is a zygote? What EXACTLY is fertilisation?
Explain the process of external fertilisation and give an example of an animal that carries it out.
External Fertilisation
Why are more eggs produced in external fertilisation?
Internal Vs External Fertilisation Internal Fertilisation Birds, reptiles, mammals Fewer gametes needed, efficient Sperm swim in body fluids Fertilised eggs protected inside mother s body or by hard shell gametes meet in a small space, increased chance of fertilisation External Fertilisation Fish, frogs, toads Many more gametes needed, wasteful Sperm swim to eggs in the water Very little protection for fertilised eggs gametes in larger space, decreased chance of fertilisation
Human Development
Human Development
Explain the role of the placenta. Give examples of useful substances that can move across. Give examples of harmful substances that can move across.
The Role of the Placenta Maternal and foetal blood do not mix, blood vessels come near each other and exchange is by diffusion Foetus gains O 2 and dissolved food from the mother Waste e.g. urea and CO 2 pass to the mother s blood for disposal by her lungs and kidneys Harmful substances such as nicotine, alcohol and drugs can cross the placental barrier and affect the foetus. Nicotine constricts the blood vessels and reduces the amount of food and oxygen reaching the foetus so the babies of smokers are smaller than those of non-smokers
What is the relationship between the number of eggs produced and the amount of care given by parents? What is the role of the yolk sac?
Number of Eggs Produced There is a relationship between the number of eggs or young produced by a species and the amount of care the young need Fish lay thousands of eggs but give them very little care and protection. The fry hatch with a yolk sac which has enough food for a few days Birds lay 6-12 eggs but care for and feed the young for several weeks Humans usually have 1 baby at a time and give them care for many years. Mammals feed their young with milk
State 2 functions of the kidneys.
Water and Waste The kidneys are the main organs of water regulation They keep the concentration of water in the body constant by controlling the volume of urine produced As well as regulating the water content of the body the kidneys filter the blood to remove toxic substances such as urea
State 2 ways water is gained by the body. State 4 ways water is lost by the body.
Water Balance
Water Gain and Water Loss
The Urinary System
The Urinary System
Draw and label a nephron. What is ultrafiltration and where does it take place? What substances are reabsorbed back into the blood?
The Nephron
The Nephron Simplified
What is urea and where is it produced? Why is the concentration of urea greater at the collecting duct than the bowman s capsule?
What is Urea? During digestion, enzymes break proteins down into amino acids, which are then built into new proteins by the liver. Any amino acids which are not used are broken down by the liver into urea. This is then removed from the blood by the kidneys.
Where is ADH released from? Describe how ADH controls water content in the blood.
The Role of ADH
Dialysis
What are the advantages and disadvantages of dialysis and a transplant?
Transplant Vs Kidney Machine Transplant Needs a donor, live or dead, may have to wait Patient must take drugs to prevent rejection but these lower resistance to disease Can lead a normal life Shortage of donors No need for a donor, no waiting Dialysis No rejection problems Needs to spend 1 or 2 nights a week on dialysis Only limited by funds and trained staff, family can train to help patient
What is the main reason animals behave the way they do?
Responding to the Environment All animals must react to changes in their environment if they are to survive. Light (day length), humidity, temperature and chemicals are some of the factors that affect behaviour.
How do woodlice react to light and dry conditions? Why?
Factor Organism Response to Change Significance Light Euglena Move to light Can photosynthesis e Light Maggots Move away from light Find food, hide from predators Chemicals Planaria Move to chemicals from food Increases chance of finding food Humidity Woodlouse More movement in dry, light areas. Less movement in damp, dark areas Breathes through skin which must be kept damp, hides from predators
What is rhythmical behaviour? Give some examples.
Rhythmical Behaviour Rhythmical behaviour in animals is triggered by regular events in the environment e.g. length of the day and night, the tide, seasons, Migration of birds such as the Barnacle goose is triggered by day length Migration of salmon is triggered by a factor or factors unknown Behaviour patterns occur at fixed periods of time e.g. once per year or day or each high tide Behaviour pattern is set off by some external stimulus called a trigger stimulus If the trigger stimulus is removed and the animal placed in constant conditions then the true rhythmical behaviour pattern will carry on e.g. shore crabs more active at the time of high tide even if kept in constant conditions.