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Adaptations to Nutrition (2.4) - Coggle Diagram
Adaptations to Nutrition (2.4)
Modes of nutrition
Autotrophic
Synthesis of complex organic chemicals from inorganic substances using an energy source
Photoautotrophic
Uses light energy to combine inorganic substances into complex organic chemicals
Holophytic nutrition
Chemoautotrophic
Uses chemical energy to combine inorganic substances into complex organic chemicals
Uses inorganic resources for energy
Extremophiles
Methanococcus - lives in the stomach of a cow
Nitrifying bacteria
Producers
Heterotrophic
Must digest organic chemicals produced by other organisms + use products of digestion to synthesise their own organic chemicals
Consumer
Holozoic
The ingestion + digestion of food
The organism does not have to remain attached to its food source to digest the food
Unicellular - Amoeba
Products of digestion are absorbed, assimilated + waste is egested
Food is ingested via endocytosis / phagocytosis + waste is expelled via exocytosis
Example of intracellular digestion
Multi-cellular
Digestive systems which carry out extracellular digestion within the organism
Absorption + Egestion
Food from others
Saprotrophic
Extracellular digestion of dead / decayed organic matter, with the secretion of enzymes
Secretion of enzymes digest the organic chemicals of the substrate which they live on, which are then absorbed
Must consume - Carbon, Nitrogen, Phosphate, Vitamins + Minerals, Energy
Parasites
Endo
Inhabits the organs of the host, can be intracellular or extracellular
Pork + Beef tapeworm
Structural adaptations
Scolex - Head of the tape worm, has hooks + suckers to hold and prevent it being dislodged
No digestive system + mouth as they absorb already digested nutrients
Thick cuticle - Resistant to digestive enzymes, can also secrete mucus + inhibitors to reduce the risk of digestion
Ecto
Headlouse
Structural adaptations
Strong claws - Clings to hair
Eggs are laid and glued to base of hair
When empty = White = Nits
Obligate parasites, no 1st, 2nd..
Head - Head transmission
Lives on the external surface of the host, infests the skin of the animal
Gains nutrients from a host, Harm is also given to the host while the parasite is achieving this process
The host gains no benefit
Primary host - Where the adult forms of the parasite develop
Secondary host - Where larval / intermediate forms of parasite are found
Vectors - Secondary hosts which actively + directly transfer the parasite from one primary host to another primary host
Malaria
Plants can be parasitic
Dodder
No leaves, no roots
Has suckers which penetrate the xylem + phloem, it is an obligate parasite (Has to live on a host to survive)
Xylem (Water + minerals)
Phloem (Sugars + Amino acids)
Mistletoe
Semi-Parasitic
Roots penetrate the xylem + phloem of host plant, but can carry out photosynthesis
Symbiosis
Organisms live in / on other organisms with a mutually beneficial relationship
Digestive systems of multicellular animals
Hydra
Has a Simple sac-like gut with one opening to the external environment
Digestion in gut cavity is a combination of chemical + mechanical digestion
Gastrovascular cavity - Where large scale digestion takes place
Food is absorbed via phagocytosis + large molecules absorbed via pinocytosis
Flatworms
Larger than the hydra, therefore has a more complex system, but still has a single gut cavity
Gastrovascular cavity is highly branched, allowing food to be digested and absorbed throughout the organisms
Humans
More complex animals like humans have a tube gut which has an opening for ingestion + another opening for egestion
Different regions of the gut are adapted for different functions
Mechanical digestion - Muscular action (Teeth)
Chemical digestion - acids
Chemical digestion - Enzymes with different optimum pH
A tube gut increases the efficiency of digestion + eat a wider array of foods
Buccal cavity
A mixture of mechanical + chemical digestion takes place
Lips, Tongue and mouth
Food is entered
Moved around
Cut, grinds, chews food into smaller pieces
Food is mixed with saliva to lubricate food
Food is formed into a bolus to make swallowing easier
1 more item...
Salivary glands secrete saliva
Makes the food moist
Slightly acid pH
Has the enzyme salivary amylase
Amylase turns Starch > Maltose
Oesophagus
A straight narrow tube with a muscular wall
Carries food to the stomach via Peristalsis
Peristalsis - Wave of contraction of muscles, takes place along the whole gut
Stomach
Chemical and mechanical digestion
Chemical - Action of enzymes + hydrochloric acid
Mechanical - Action of muscles in the stomach contract + relax to mix food with gastric juices to break large particles of food into smaller particles (Larger s.a for chemical action)
End result - A semi-liquid called "Chyme"
Small intestine
Villi - Wall is folded, for increased s.a for digestion + absorption
Intestinal glands located at the base of the villi
Brunner glands - Secretes alkaline fluid to neutralise "Chyme"
Duodenum - First part of the S.I
About 30cm
Receives secretions from accessory organs
Liver - Bile
Pancreas - Pancreatic juice
Iluem - Second part of the S.I
5m long
Increases time to pass through
More time for absorption
Main site of absorption of digestion + water
Villi increases the surface area greatly + has a rich blood supply making it more efficient at absorbing the products of digestion
Large intestine
Caecum - First part of the L.I
Has no use in humans
Digests cellulose in some animals
Colon - Second part of the L.I
The rest of the water and mineral salts are absorbed
Formation of faeces - Vitamins produced by microorganisms in the colon are also absorbed into the blood. This leaves a semi-solid mass of undigested food, dead intestinal cells and bacteria
The main part of the Large intestine
Rectum - Last part of the L.I
A muscular tube that temporarily stores the faeces before secretion
Anus - Composed of sphincter muscles, controls when defaecation occurs
Accessory organs
Liver produces bile by breaking down Hb, bile is stored in the gall bladder + secreted into duodenum through the bile duct
Liver
Excess glucose stored as glycogen
Amino groups removed from amino acids + converted to Urea
Vitamins are stored in the liver
Pancreas
Endocrine
Secretes insulin + glucagon to control blood glucose levels
Exocrine
Secretes pancreatic juice
Composed of
Enzyme
Enzyme activators
Sodium Hydrogen Carbonate
Tissue layers in the gut wall
Serosa - Connective tissue carrying blood vessels, lymphatic vessels + nerves
Longitudinal + Circular muscle - Peristalsis
Submucosa - caries the main arterioles + venules and may have glands
Muscularis mucosa - thin layer of muscle used in move the inner wall of the gut
Mucosa - Covered by a layer of epithelial cells - some produce mucus, others are utilised at the final stages of digestion and absorption of nutrients
Adapted by having folds in the wall to increase s.a
Inner surface is further folded to form villi
Surface of the epithelial cell covering the villi is further folded to form microvilli
Adaptations of villus
Rich capillary network - absorbs + removes products of digestion and mains conc. grad.
Lacteals to absorb the products of fat digestion and maintains conc. grad.
Thin - reduces diffusion distance
Microvilli - increases s.a
Epithelial cells contain a large numbers of mitochondria to provide ATP for Active transport
Digestion + Absorption in mammals
pH
Enzymes present will have different pH optima, even while they digest the same food
As enzymes pass from one region to another they are deactivated as a result of diff. in pH
Some protease enzymes are secreted as enzyme deactivators to prevent Autolysis
Autolysis - Self digestion
Dentition
Herbivores
Teeth are adapted to grind plant tissue
Plants contain a large amount of cellulose + other fibres, that protects the cells contents, making it hard and less nutritious
Masseter muscle is large for grinding
Molars + premolars are ridged to assist with grinding / mechanical digestion of grass
No incisors on the upper jaw, and diastema present between the modified canine and first premolar
Can divide the buccal cavity into two with their tongue and can chew food with their molars + premolars while eating with their incisors at the front of the mouth
A "horny pad" may be present up top to assist grinding, with the molars + premolars
Carnivores
Incisors + canines adapted for biting + gripping prey
Premolars + molars are called the carnassial teeth
Has a single ridge + slides past each other, acts like scissors shearing flesh from bone
Most do not chew their food before swallowing, but need to hold on their prey when hunt + exert great force when eating (Cracking bones), present in their jaw muscles
Mainly animal tissue rich in protein + fat, easier to digest
Stomach is large to increase digestion of protein
Omnivores
Eat a mixed diet, digests a whole range of foods
Teeth
Incisors - Biting + tearing flesh
Canine - Grips prey
Molars + Premolars - Adapted for grinding plant tissue (Herbivores + Omnivores) or shearing flesh from bones (Carnivores)
Other Diets
Insectivore
Insects made of chitin + protein
Easily digestible material
Short gut as products of digestion are easily absorbed
Non-ruminant herbivore
Base of the oesophagus is expanded and leads to three chambers, these chambers have bacteria + archaea which digests cellulose + produces fatty acids, proteins + vitamins
Protein digestion begins in the abomasum (True stomach), absorption occurs after the site of bacterial digestion, therefore digestion is more efficient.
They regurgitate their food after bacterial digestion in the rumen, and chewed a second time to further breakdown the tough fibres + release more nutrients
Ruminant herbivore
Plant with high fibre is hard to digest, therefore bacteria / archea is present in caecum
Caecum digests cellulose + produces protein, since it occurs after the ileum, products are not absorbed therefore some animals like rabbits will eat their faeces to reabsorb nutrients
However animals like horses do not consume their faeces meaning their digestion and absorption is less effective
A ruminant "Stomach" is well adapted to a plant diet with 4 chambered "stomach"
Animal first swallows food and enters reticulum, large objects like stones are collected here
Liquids pass into the omasum + solids pass into the rumen and reticulum and are also regurgitated and chewed again (Up to 10 times)
In the rumen, bacteria, archaea and protoctista digest the cellulose cell walls which releases cell contents
Microbes produce small fatty acids + B vitamins which provide additional nutrition to the animals
Microbes use protein released from the cells for their own group
Contents of the rumen eventually pass into the omasum where water and minerals are absorbed. This is before the true stomach the Abomasum
This is where bacterial and remaining dietary protein begins to be digested
Young ruminants feed on milk
Food passes from base of oesophagus directly to the abomasum
Milk is high in protein, and only the abomasum is needed for protein digestion
No milk intake in adults - their diet is high in cellulose + low in protein
In adults the rumen is largest part of the stomach as most food digested is cellulose