Download Chapter 6, lesson 1: How Animals Get and Digest Food

Biology: Chapter 6, lesson 1: How Animals Get and Digest
Food. (notes)
 Animals cannot
their own food.
 Must
from other organisms
 Different animals = different ways of getting food
 Filter feeding:
 Filtering or
food particles from the
. Food must be tiny.
 Many animals that live in water use this method.
 Animals that
move to get food:
 Sponges – filter through
.
 Barnacles – use
(act like screens)
 Mollusks – use
.
 Animals that can
:

– swim with mouth open,
capturing millions of tiny organisms and filtering
through their baleen (combs of thick hair in place of
teeth).
 Feeding on Fluids (liquids):
 Getting food from the
of plants or other
animals.
 Fluids are rich in
.
 Aphids and cicadas: have
mouthparts
to draw
from plants leaves, roots, and stem.
 Bees, butterflies, and hummingbirds: draw
from flowers
 Spiders and assassin bugs: suck fluids from captured
.
 Leeches, mosquitoes, and horse flies: suck
from vertebrates.
 Consuming Large Pieces of Food:
 Most animals
(eat) large pieces of
solid food.
 Use different kinds of body structures to capture and
consume food.
 Cnidarians: use
with stinging cells
to capture food and eat it whole.
(chapter 6, lesson 1 continued)
 Insects: many have
suited for
cutting or chewing.
 Grasshoppers, termites, and beetles feed on
– herbivores

: animals that eat only plants or
plant parts
 Dragonflies and praying mantises eat other
– carnivores

: animals that eat only other
animals (meat).
 Omnivores: animals that eat both plants and
animals. (example: human and bears)
 Vertebrates: the only animals with
(not
all have them).
 Different shapes and sizes do different jobs.

at front of mouth:
cut food into pieces (incisors = the ones you bite
with)
 Long,
teeth: grip and pierce
food (canines = “fangs”)

surface: grind and crush food
(premolars and molars = the ones you chew with).
 Teeth type tell what
an animal eats:

: long canine teeth and sharp,
pointed molars = tear
.

: use incisors to clip plants,
large molars with flat surfaces = grinding
.
 Omnivores: have a combination of the types of teeth
= tear flesh and grind plants.
 Digesting Food:
 Food contains
.
,
, and
 Provide
that an animal needs.
 Food is too large for most animal cells to absorb
 Must be broken down into
chemicals
 This process is called
.
(chapter 6, lesson 1 continued)
 Digestion occurs by
digestive
:
 Secreting = “form and
.”
 Enzymes = substance that
a
chemical change in living things.
 Digestion
cells:

: cells trap food particles and
package them into
(storage
organelles inside the cell) where digestive enzymes
break down the food and then the cell absorbs the
“food” chemicals from the vacuoles.
 Drawback: food must be
enough
to fit inside vacuoles  tiny food particles.
 Digestion
cells:
 Most other animals: eat food, digestion occurs outside
cells, then “food” chemicals are absorbed by the cells.
 Advantage: can eat much
foods.
 Gastrovascular Cavities: (cavity = open space, like a cave)
 (lower animals) Cnidarians and flatworms digest food in a
 gastrovascular cavity.
 Only have
opening = the mouth.
 Food enters mouth  special cells in cavity secrete
digestive enzymes that break down the food  cells
absorb particles.
 Material not digested leaves through the
.
 Digestive Tracts: (tract = path)
 More developed (higher) animals have a
.

digestive space with an opening
at
end.
 Food moves in
direction only  entrance to exit
 Different parts of tract carry out different functions.
 Main functions:

food

food

nutrients
(chapter 6, lesson 1 continued)
 Most digestive tracts are organized in the same way with some
differences.
 Example: Birds
 Food enters through the
.
 Travels through the
to the
: food storage.
 Passes to
: food mixes with
and digestive enzymes.
 Mixture moves to
:
food into watery paste.
 Moves into
: more enzymes
added, nutrients absorbed through intestine wall, and
water is absorbed (to make feces solid).
 Digestion is completed here.
 Anything that can’t be digested: leaves body through the
.
 Humans and other mammals: don’t have a crop or gizzard

carries out the functions: food
storage, mixing with acids and enzymes, and grinds food
to watery paste (chyme).