Transcript Animal Digestion Reproduction

How animals obtain nutrition
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Mouth – takes in food
Esophagus – transports food from mouth to
stomach(s)
Stomach
 Crop – stores food
 Gizzard – grinds food
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Intestine – absorbs nutrients
Rectum/anus – expels waste
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Ingest soil, remove nutrients
http://www.ncsu.edu/scivis/lessons/earthworm/Overview.html
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Eat other fish (and their eggs), insect larva,
worms, shrimp, plankton, algae…
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Eat snails, insects, worms
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Eat small invertebrates, mammals,
amphibians, other reptiles, and plants
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Eat seeds, nectar, fruit, insects, worms, fish
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Herbivores
Carnivores
Omnivores
How animals make offspring
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Asexual – a genetically identical copy is made
from one parent; NO VARIATION!
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Sexual – fusion of gametes (ex. sperm and
egg); combination of genetic material from
two parents
 Children are similar to but different from each
other and parents
 VARIATION!!!
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Hermaphrodites
Can fertilize each other
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Male and female
Internal fertilization
2 kinds of life cycles
 Incomplete metamorphosis (gradual growth)
▪ Egg-nymph-adult
 Complete metamorphosis (juvenile goes into
dormant stage, then changes to adult)
▪ Egg-larva-pupa-adult
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Females lay unfertilized eggs (“spawning”)
Males deposit sperm on top of eggs
“external fertilization”
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Male sits on top of female until she lays
unfertilized eggs (“amplexus”)
External fertilization
Many different mating calls
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Internal fertilization (male puts sperm inside
female’s body)
Hard-shelled (“amniotic”) egg is laid
External development – babies develop
outside female’s body
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Internal fertilization, external
development
Many different courtship
dances
High level of parental care
http://australianscreen.com.au/titles/echidnasurvivor/clip3/
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Internal fertilization, internal development (most)
3 kinds of mammals:
 Placental
▪ Develops fully in womb, nourished by placenta
 Marsupial
▪ Partially develops in womb, then in pouch
 Monotremes
▪ Lay eggs