Adaptation and Nutrition Flashcards
Dentition?
- teeth = important in mechanical digestion of food. Chewing is important - makes it easier to swallow+ increases S.A for enzyme action.
- human teeth = unspecialised as we’re omnivores.
Incisors : 8 chisel shaped teeth for biting/cutting
Canines : 4 sharp teeth for biting/cutting/ tearing flesh
Molars/pre molars : 20 large flat teeth adapted for chewing/ grinding
Adults have 32 teeth, infants 20
Features of a grazing herbivore dentition?
• e.g cows/ sheep
- Incisors : only on lower jaw and cuts against horny pad on upper jaw
- Canines : not distinguishable from incisors
- Diastema : a gap that separates front teeth from side teeth/pre molars. The tongue operates in this gap moving cut grass to molars/pre molars.
- Jaw movement : circular grinding action in a horizontal plane
- Molars : teeth cheek interlock and have ridged enamel to increase efficiency of grinding
- Open roots : teeth has O.R so they continue to grow throughout life of animal
Carnivore dentition?
• e.g tigers
- have teeth adapted for catching/killing prey, cutting/ crushing bones and tearing meat
- Sharp incisors : grip/tear flesh from bone
- Large curved/pointed Canines : seizing/killing prey and tearing flesh
- Molars/Pre molars : cutting/crushing
- Carnassials : specialised teeth that slide past each other like blades of gardening shears
- Jaw muscles : powerful, enable carnivore to grip prey firmly/crush bone
- Jaw movement : verticle allowing jaw to open wide to capture/kill prey
Non-ruminant herbivores?
• e.g rabbits
- caecum = enlarged to accommodate cellulose digesting bacteria
- bacteria are towards end of gut, regurgitation ain’t possible so refection occurs, where rabbit ingests faecal pellets so material passes through guy 2x to increase efficiency of digestion
Adaptation of gut, ruminant herbivores?
• e.g cows/sheep
- mainly eat grass/forage which consists of cellulose cell walls but they lack ability to produce cellulase enzymes so cannot digest cellulose
- to overcome this, they have specialised composed of 4 chambers. One of these chambers, rumen is where mutalistic bacteria live.
Cellulose digestion:
•the grass is chopped by teeth, mixed w/saliva and cud is formed and swallowed
•in rumen, first region, cud is mixed with cellulose digesting bacteria to produce glucose. This is fermented to form organic acids that are absorbed into blood and provide energy for cow. Waste products CO2/CH4 are passed out. Saliva contains urea which bacteria can use as nitrogen source to manufacture amino acids/proteins
•cud passes to next region ( reticulum ) before being regurgitated to mouth via reticulum and chewed again.
•cud passes directly to 3rd region ( omasum ) where water is reabsorbed
• abomasum (true stomach) where protein is digested
• bacteria in rumen is kept seperate from acid and found in abomasum. Once it enters there they are killed by acid and provide important source of protein for animal
Definition of parasite?
• organisms that live on or in another organism called host and obtain nourishment and causes harm to host
Pork Tapeworm?
- has 2 hosts -> human is primary host where it lives in intestines, pig is second host where it lives in the muscle as cyst.
- head = scolex on which are hooks and suckers.
- body consist of thin segments = proglottids
What precaution should be taken to avoid been infected with tapeworm?
• throughly cook pork before eating
• don’t allow pig to eat human faeces
- keep away from sewers/drains
• don’t use human faeces as manoure to fertilise soil
Problems faced by tapeworm and adaptations the tapeworm has evolved?
• Gut is in constant motion ( peristalsis )
- become attached to guy as by hooks and suckers
• Extreme pH along gut, exposure to digestive enzymes and hosts immune response
- body covering which protects worm from hosts immune response.
- thick cuticle and production of inhibitory substances on surface of body segments prevents their digestion by hosts enzymes
• Host death : if host for so does worm so adult worm cause discomfort to host
• Reproduction : male and female reproductive organs so don’t need no mate. Can produce loads of eggs. Mature segments pass out of body as faeces. Eggs have resistant shells which can survive until eaten by secondary host
Why does tapeworms not require digestive enzyme?
How is it adapted to gain it’s nutrients?
- they live in small intestines of host where the host digestive system has already digested the food
- thin, long and flat so has a large S.A:V so can absorb soluble nutrients over entire body surface
Adaptation for different diets?
- Reptiles/ amphibians swallow food immediately after being caught - mammals food is retained in mouth whilst cut/chewed
- mammals have a palate - separates nasal cavity from mouth - allows food to retained in mouth rather than swallowed whole. Different mammals have different gut/dental adaptation specialised to diet
What are autotrophs and what are the two types of autotrophic nutrition?
• these are organisms that make their own food
The two types of autotrophic nutrition:
- Photosynthesis : green plants, algae and some bacteria they carry out this to make organic molecules from inorganic molecules e.g CO2+H20 using energy from sun which is absorbed by chlorophyll
- Chemosynthesis : carried out by autotrophic bacteria. They use enery derived from respiration reactions to synthesis food from inorganic molecules
What are heterotrophs?
What are the different types?
• cannot make own food, they consume organic food material produced by autotrophs.
- Holozoic feeders : have specialised D.S
Carnivores+Detritivores feed on dead/decaying material. Herbivores feed on plants and omnivores eat plants/animals - Saprophytes: e.g fungi feed on dead/decaying material, NO specialised D.S. Feed by secreting extracellular enzymes e.g amylase, lipase, cellulase onto food material outside body. Absorb soluble products of digestion e.g glucose monomers by DIFFUSION
- Parasites : ( definition ) some live in body of host while some on surface
- Mutualism : a.k.a symbiosis which involves close association between 2 members of 2 diff species which both organisms benefit from relationship e.g digestion of cellulose by microorganism in gut of herbivore
Human digestive system? ( alimentary canal )
made in Chelsea, Eastenders , a minute to countdown
- Mechanical digestion : teeth - achieved by the cutting and crushing action of teeth stomach - muscular contractions which churn the food and mix it with gastric secretions.
- Ingestion : food taken into mouth, chewed and a bolus is formed then swallowed
- Chemical Digestion : enzymes are secreted in various parts of the D.S. Large molecules are broken into smaller molecules increasing S.A over which enzymes can act
- Egestion : food that cannot be digested/absorbed is expelled as faeces, mainly dietary fibre ( cellulose ) , bacteria and dead cells
- Absorption : small soluble molcules ( p.o.d ) are absorbed into bloodstream ( small intestines ) water is also absorbed ( large intestines )
Structure of mammalian gut wall?
outwards in
- Serosa : tough outer connective tissue, that protects the gut wall and reduces the effect of friction on other organs
- Muscularis : consists of 2 layers of muscle running in different directions - the inner circular muscle and the outer longitudinal muscle. These muscles cause contractions which propel food along gut by peristalsis. Behind the bolus the circular muscles contract and longitudinal relax to move the food along. After the bolus moves down the circular muscles relax while the longitudinal contracts
- Sub Mucosa : connective tissue that contains blood and lymph vessels to take away absorbed food products as well as nerves that coordinate muscular contractions involved in peristalsis
- Mucosa : inner most layer and lines w/ gut wall. Secretes alkaline mucus which lubricates bolus helping it move along D.S and protects the mucosa from action of digestive enzymes
- the villi increase S.A for absorption of digested food
