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Modes of Nutrition

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Title: Ecosystems & Energy Flow Author: owen-a Last modified by: owen-a Created Date: 3/30/2006 1:49:02 PM Document presentation format: On-screen Show – PowerPoint PPT presentation

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Title: Modes of Nutrition


1
Modes of Nutrition
2
Modes of Nutrition
  • AUTROPHIC ORGANISMS
  • Use external sources of energy to synthesise
    their own organic food materials, which are often
    expired to release energy
  • Photosynthetic organisms use light energy eg
    plants or algae
  • Chemosynthetic organisms use energy from chemical
    reactions eg some prokaryotes

3
Modes of Nutrition
  • HETEROTROPHIC ORGANISMS
  • Use ready made organic food materials by feeding
    on plants/algae or animals that have eaten plants
    or algae. Energy is released from the food by
    respiration
  • Four types of heterotrophic nutrition
  • Holozoic
  • Saprobiontic
  • Parasitic
  • Mutualism

4
Holozoic Nutrition
Involves 5 separate stages and a specialised
gut - ingestion - digestion - absorption -
assimilation - egestion Two main types -
HERBIVORES CARNIVORES
5
Herbivores
  • eg ruminants (cattle sheep). Adaptations to
    a diet containing large quantities of cellulose
  • Specialised dentition
  • No upper incisors horny gum pad only
  • Small lower incisors and canines that cut / grip
    against horny pad
  • Diastema
  • Premolars and molars for grinding with ridges of
    enamel
  • Open roots
  • Loose jaw articulation

6
Herbivores
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Herbivores
  • eg ruminants (cattle sheep). Adaptations to
    a diet containing large quantities of cellulose
  • Complex gut containing 3 additional compartments
  • rumen
  • reticulum
  • omasum
  • true (gastric) stomach (abomasums) is also
    retained

9
Ruminant Digestion
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11
Herbivores
  • eg ruminants (cattle sheep). Adaptations to
    a diet containing large quantities of cellulose
  • Complex digestion
  • Food enters rumen for up to 30hrs
  • Coarse material regurgitated re-swallowed
  • Microbes digest cellulose to hexoses
  • Fermentation
  • Proteins also broken down by microbes

12
Carnivores
  • eg dogs show adaptations to a diet consisting
    of other animals
  • Specialised dentition
  • Sharp incisors
  • Large canines
  • Carnassial teeth
  • Sharp pointed premolars and molars
  • Tight jaw articulation
  • Simple gut

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Carnivores
  • eg dogs show adaptations to a diet consisting
    of other animals
  • Adaptations for hunting
  • Forward facing eyes
  • Night vision
  • Speed
  • Camouflage
  • Claws
  • Some hunt socially

15
Saprobiontic Nutrition
  • eg many bacteria fungi
  • Primary consumers in detritus food chains
  • Extracellular digestion
  • Eg Rhizopus (bread mould)
  • Mycelium made up of aerial hyphae called stolons
  • Secrete enzymes
  • Products absorbed used for metabolism or stored

16
see figure 6.6 page 119 NAS
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Parasitic Nutrition
  • live in close association with another organism
    (host). Dependent on host for food
  • Ectoparasitic or endoparasitic
  • Usually cause some harm to host
  • Eg Taenia (pork tapeworm)

19
Parasitic Nutrition
  • Taenia solium the pork tapeworm
  • Adult stage in human small intestine
  • Protected from host enzymes
  • Anterior end is scolex
  • Zone of proliferation proglottids form long
    thin
  • Self fertilisation
  • Larvae develop in muscles of pig

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Mutualism
  • When two organisms live in a close relationship
    in which both contribute and both benefit
  • Eg nitrogen fixing bacteria Rhizobium and members
    of the Papilionacceae (pea plant family)
  • Rhizobium benefits from a source of carbohydrates
    from plant
  • Plant benefits from a source of ammonia / amino
    acids from the Rhizobium

23
Mutualism
  • Rhizobium attracted to plant roots
  • Rhizobium penetrate root hair cells
  • Rhizobium moves into root cortex stimulates
    auxin production
  • Nodules form containing large numbers of
    Rhizobium
  • Bacteroids form, able to fix nitrogen in
    anaerobic conditions
  • Leghaemologlobin pigment absorbs oxygen molecules
  • Rhizobium uses hydrogen (from carbohydrates of
    plant) to combine with nitrogen gas forms
    ammonia

24
Modes of Nutrition exam questions
25
Modes of Nutrition
  • Study diagram A and answer the following
    questions
  • Describe how the jaw action of herbivores such as
    sheep uses the interlocking surfaces of these
    teeth to chew plant material (2)
  • Suggest the function of the region labelled X (2)
  • Explain the importance of the rumen in digestion
    (2)
  • Describe three differences between the teeth of
    the sheep and the dog. For each difference,
    explain how it is related to the differences in
    their diets (6)

26
Modes of Nutrition
1. Describe how the jaw action of herbivores such
as sheep uses the interlocking surfaces of these
teeth to chew plant material (2) - Side to side
/ rotating / circular movements of jaw - Ridges
of enamel on teeth act as cutting edges -
Interlocking surfaces for grinding
27
Modes of Nutrition
2. Suggest the function of the region labelled X
(2) - Manipulation of grass / food - To expose
different surfaces to teeth - To keep chewed
grass separate from fresh grass
28
Modes of Nutrition
3. Explain the importance of the rumen in
digestion (2) - Fermentation / breakdown /
digestion of cellulose / fibrous material / cell
walls - By microorganisms / gut fauna / bacteria
/ protozoa - Regurgitation / rechewing - Storage
or time for action of bacteria / explanation of
second digestion
29
Modes of Nutrition
4. Describe three visible differences between the
teeth of the sheep and the dog. For each
difference, explain how it is related to the
differences in their diets (6) 1 (a) Incisors in
sheep on lower jaw only OR reference to horny pad
on upper jaw. Incisors in dog present on upper
and lower jaw (b) Chopping / cutting / cropping /
tearing in sheep gripping / nibbling in dog
30
Modes of Nutrition
4. Describe three visible differences between the
teeth of the sheep and the dog. For each
difference, explain how it is related to the
differences in their diets (6) 2 (a) Canines are
small / absent / only in lower jaw in sheep.
Canines are large / pointed in the dog (b) Dogs
require large pointed canines for gripping /
stabbing
31
Modes of Nutrition
4. Describe three visible differences between the
teeth of the sheep and the dog. For each
difference, explain how it is related to the
differences in their diets (6) 3 (a) Sheep have
diastema (gaps between canines / incisors and
premolars). Dog has no gap. (b) Used in sheep
for manipulation of food bolus (by tongue)
32
Modes of Nutrition
4. Describe three visible differences between the
teeth of the sheep and the dog. For each
difference, explain how it is related to the
differences in their diets (6) 4 (a) Premolars /
molars of sheep are ridged, interlocking / not
sharp. Premolars / molars of dog are pointed /
sharp / not interlocking. (b) Sheep grind food.
Dogs slice / shear / cut / crush bone.
33
Modes of Nutrition
5 State where the adult stage of Taenia would be
found in the body of the host mammal
(1) 6 Explain how the hooks and suckers enable
Taenia to be a successful endoparasite (2) 7 Give
two features of Taenia, other than those in the
picture that are adaptations to the parasitic
mode of nutrition (2) 8 Explain how the mode of
nutrition shown by a parasite, such as Taenia,
differs from that shown by a fungus, such as
Rhizopus (3)
34
Modes of Nutrition
5. State where the adult stage of Taenia would be
found in the body of the host mammal (1) - Small
intestine / ileum / duodenum
35
Modes of Nutrition
  • 6. Explain how thye hooks and suckers enable
    Taenia to be a successful endoparasite (2)
  • Enables grip to the walls of the alimentary canal
  • Prevents it being carried away by peristalsis

36
Modes of Nutrition
  • 7. Give two features of Taenia, other than those
    shown in the picture, that are adaptations to the
    parasitic mode of nutrition (2)
  • No mouth / alimentary canal / digestive system
  • Lack of sense organs / reduced nervous system
  • Thick, enzyme resistant tegument/coat/covering/cut
    icle OR mucus secreted to protect against enzymes
  • Can tolerate low oxygen / anaerobic conditions
  • Prolific reproductive capacity - hermaphrodite
  • Flat body shape / large surface area to volume

37
Modes of Nutrition
  • 8. Explain how the mode of nutrition shown by a
    parasite, such as Taenia, differs from that shown
    by a fungus, such as Rhizopus (3)
  • Rhizopus is a saprophyte / saprobiont /
    saprotrophic
  • Parasites feed from / live on host, Rhizopus
    feeds on / lives on dead material
  • No digestion of food / food already digested in
    Taenia and external digestion of food in Rhizopus
  • Absorption of food over whole body surface in
    Taenia and reference to mycelium / hyphae in
    Rhizopus

38
Modes of Nutrition
  1. State the mode of nutrition carried out by
    Rhizopus (1)
  2. Explain how the hyphae are involved in the
    nutrition of Rhizopus (3)
  3. Rhizopus is an example of a heterotrophic
    organism. Explain how heterotrophic nutrition
    differs from autotrophic nutrition (2)

39
Modes of Nutrition
  • 9. State the mode of nutrition carried out by
    Rhizopus (1)
  • Saprotrophic / Saprobiontic / Saprophytic

40
Modes of Nutrition
  • 10. Explain how hyphae are involved in the
    nutrition of Rhizopus (3)
  • Hyphae penetrate food/substrate forms large
    surface area in contact with food anchors
    organism onto substrate
  • Secretes enzymes onto substrate
  • Named enzyme and substrate hydrolysis /
    breakdown of large compounds to small
  • Uptake/absorption of soluble products of
    digestion
  • Reference to external / extracellular digestion

41
Modes of Nutrition
  • 11. Rhizopus is an example of a heterotrophic
    organism. Explain how heterotrophic nutrition
    differs from autotrophic nutrition (2)
  • Heterotrophs take in / cant make organic
    compounds. Autotrophs use inorganic compounds
    and synthesise organic compounds
  • Heterotrophs rely on other organisms. Autotrophs
    use light / external energy / photosynthesis.

42
Modes of Nutrition
  • Use the information sheet Mutualism to answer
    the following questions
  • 12 The relationship between Rhizobium and a
    legume crop is an example of mutualism. Explain
    what is meant by the term mutualism (2)
  • State which of the species of bacterium would
    have been in the inoculant used in the field
    trials (1)
  • Explain why the addition of the Rhizobium
    inoculant to the soybean crops in the field
    trials increased the yield of beans (4)
  • Compare the effect of the addition of the
    inoculant in South Dakota and Iowa (2)
  • Suggest a reason for the difference you have
    described (1)

43
Modes of Nutrition
  • 12. Explain what is meant by the term mutualism
    (2)
  • Involves two species / types of organism
  • Benefits both

44
Modes of Nutrition
  • 13. State which species of bacterium would have
    been in the inoculant used in the field trials
    (1)
  • japonicum

45
Modes of Nutrition
  • 14. Explain why the addition of the Rhizobium
    inoculant to the soybean crops in the field
    trials increased the yeild of beans (4)
  • Rhizobium is a nitrogen fixing bacterium
  • Converts nitrogen to ammonia / ammonium compounds
  • Reference to nitrogenase
  • This is used to form amino acids / proteins
  • Added to those in soil
  • Therefore more protein for growth

46
Modes of Nutrition
  • 15. Compare the effect of addition of the
    inoculent in South Dakota and Iowa (2)
  • South Dakota has a greater increase in yield
  • X10 greater / 6.4 more
  • 16. Suggest a reason for this difference (1)
  • Climate / weather
  • Soil types / fertiliser
  • Difference in natural Rhizobium
  • Possibility of diseases

47
Ecosystems Energy Flow
48
Ecosystems Energy Flow
Candidates should be able to recall the
terms biosphere, ecosystem, habitat, producers,
consumers, decomposers, trophic levels, food
chains and food webs
49
Ecosystems Energy Flow
ECOSYSTEM A stable, settled unit of nature
consisting of a community of organisms
interacting with each other and with their
surrounding physical and chemical
environment. Eg Pond Forest Sea shore -
Savannah
50
Ecosystems Energy Flow
An ecosystem consists of two components
BIOTIC
ABIOTIC
Factors that affect the way in which organisms
grow and carry out their activities Light Temperat
ure Water Soil - etc
All living organisms that regularly come into
contact with each other Producers Consumers Decom
posers
51
Ecosystems Energy Flow
BIOSPHERE The restricted zone in which living
things inhabit. For the majority of organisms
this is from the upper soil to the lower
atmosphere.
52
Ecosystems Energy Flow
HABITAT The locality in which an organism occurs
(where the organisms is normally found) Can be a
microhabitat
53
Ecosystems Energy Flow
Producers Consumers Decomposers
54
Ecosystems Energy Flow
REVISION Food Chains Food Webs Pyramids of
number Pyramids of Biomass
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Biomass the mass of organisms per unit area of
ground, kg per hectare. May be converted to an
energy value, kj per hectare.
59
Ecosystems Energy Flow
Transfer of energy Energy from the sun, trapped
by photosynthesis, provides the source of energy
for all living organisms 0 5 joules solar
energy per sq metre / min Only small absorbed
by chlorophyll and converted into chemical
energy Reflected passes through wavelengths
not used in photosynthesis Wastage due to
biochemical inefficiency of the reactions of
photosynthesis
60
Ecosystems Energy Flow
Transfer of energy through food chains Grass -
fix 1 suns energy falling on leaves Grasshopper
- incorporates 10 of energy available into
own biomass Mouse - only 10 of the energy
available in the grasshopper converted into own
biomass So no more than 5 trophic levels!
61
Ecosystems Energy Flow
Primary Productivity The rate at which biomass
is produced per unit area by green
plants Expressed as mass or energy Rate of
accumulation of biomass kilojoules per unit area
per year (kj ha -1 yr -1) or kg.
62
Ecosystems Energy Flow
Gross Primary Productivity (GPP) The total amount
of energy captured by green plants in
photosynthesis kj / m2 / year Plant uses some
organic materials produced GPP ultimately lost
as heat The rate at which these are used plant
respiration (R) kj / m2 / year
63
Ecosystems Energy Flow
Net Primary Productivity (NPP) The difference
between GPP and losses due to respiration Represen
ts the biomass available for consumption by
heterotrophs
64
Ecosystems Energy Flow
Pyramid of energy Shows productivity for each
level in ecosystem Productivity is a measure of
the energy content of each level Can be obtained
by converting the mass of new organic material
produced per unit area per year into an
equivalent energy value kj m -2 yr -1
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