Download Animal Nutrition (Ch. 41) Examples: Python Starfish Digestion in

Animal Nutrition (Ch. 41)
http://www.youtube.com/watch?v=vJvfjiCTvq4
Examples:
Some of the best known and
fascinating adaptations of animals
involve their feeding and digestion
Python
http://www.youtube.com/watch?v=aDW5HpdFals
• Reptile swallowing prey
• Baleen whales
Starfish
http://www.youtube.com/watch?v=i-EJuL0ix5Q
www.youtube.com/watch?v=rE8l-KFQlhY
Digestion in
Paramecium
Extracellular digestion
Gastrovascular
cavity: Hydra
Gastrovascular cavity vs. Alimentary
Canal
• A. outside organism
• B. gastrovascular cavities
• C. alimentary canal
Alimentary canal: a simple view
Basic parts of alimentary canal
Mechanical
digestion
storage
absorption
mouth
anus
Alimentary canal: mammalian
Mouth
Stomach
• Mechanical
• enzymatic
Digestive
mechanisms in
stomach
Stomach
http://www.youtube
.com/watch?v=umn
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http://www.youtube
.com/watch?v=Ln0
9qihUi3g
http://www.youtube
.com/watch?v=Uzl6
M1YlU3w
• Mechanical
• Chemical
• enzymatic
Digestive
mechanisms in
stomach
• Mechanical
• Chemical
• enzymatic
Mechanical
• Mixing and churning
Chemical
• pH around 2
Enzymatic
• Pepsin
– Also breaks food down
– Breaks down proteins
Activation of
pepsin
Why doesn’t
pepsin digest
stomach?
Small intestine
• Most of the
enzymatic
digestion occurs
here
Why doesn’t the small intestine digest
itself?
Fig. 37.13
Most nutrient
absorption takes
place in small
intestine
• Structure: another
example of
increasing surface
area
Microvilli
Structure of
small intestine
Large intestine
(colon)
• Major function is
to reabsorb water
Variations of vertebrate digestive
system
• Herbivorous mammals
– Specialized fermentation chambers
Why does herbivory require
specializations?
Coyote vs.
Koala
Structure of cellulose
Campbell 6th
ed p. 68
Horse cecum
• Plant tissue
– Harder to break up
– Contains cellulose
– Nutrients less concentrated than meat
Campbell 6th
ed p. 867
Cecum
• Allows breakdown of
cellulose in
herbivores
• One opening and exit
- lower oxygen,
slower passage
• Digested cellulose
must be reintroduced
to digestive system
Ruminant digestion
Campbell 6th
ed p. 868
Ruminant 4 chambered stomach
Part of
Campbell 6th
ed p. 867
• Rumen and reticulum - where symbiotic
bacteria and protists break down cellulose
• Cow rechews food
• Omasum - where water is absorbed
• Abomasum - further digestion by cow’s
enzymes
http://www.youtube.com/watch?v=pbeI4aiSLyg
Symbiosis
Autotroph-invertebrate symbiosis
• Symbionts are algae
• Algae photosynthesize and provide molecules
such as sugars to the host
• Hydra, anemones, giant clams, corals
Examples
•
•
•
•
Sea anemone
chloroplasts in plants
coral reef
corals (like anemone and green hydra)
Examples
http://www.youtube.com/watch?v=5d3qie3jbHk