BIOB34H3 Lecture Notes - Lecture 1: Phospholipid, Glycogen, Gastrulation
BIOB34 LECTURE NOTES
LECTURE #1
-Historically, single-celled
eukaryotes with animal-
like behaviour were called
Protozoans whereas single-
celled eukaryotes with
plant-like behaviour were
called algae. The species
count includes extinct
animals.
-Metazoa is the older
taxonomic name
proto = first animal à
first groups with animal
like behaviour
meta =
later/subsequently à
derived and more
complex animals
-Eventually protozoans were put into the protist kingdom
FUNDAMENTAL CHARACTERISTICS OF ANIMALS (Metazoa)
1) Eukaryotic
2) Multicellular
3) Diploid-Dominant
4) Lack Cell Walls
5) Chemoheterotrophic
6) Motile* and Quickly Responsive to External
Stimuli due to Muscle and/or Nervous Tissue
7) Development via Blastula and Gastrula Stage
-All cells making up animals
are eukaryotes
-Multicellular nature means
specialized +
interdependency
-Plants are prominent haploid,
animals’ diploid
-Animals typically use structural proteins to do the fxn of cell walls
-Chemo = oxidation of molecules
-#7 is the defining char. Of animals
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-Blastula = hollow ball of cells (blastocoel is the inside) à those balls will undergo
gastrulation to invaginate the out portion inwards and becomes a mouth
-Adult sponges are sessile, but their offspring are
motile before they become adults
-Sponges are filter feeders, passing water through their
bodies and catching
food from the water as it
moves through their
body, responding to
the stimuli they feel when particles are caught in their
mucus-like internal ‘net’
-Sponges stop filter feeding when the filter systems gets
clogged by big particles, so they stop filter feeding for a
few seconds to a minute (this is how they respond to
stimuli)
-Animals develop from a blastula and a gastrula stage
-humans are
coelomates, round-
worms are pseudo-coelomates,
and flatworms are accelomates
-humans have multicellularity,
true tissues, germ layers, bilateral
symmetry, 3 germ layers, and deuterosome
development
LECTURE #2
METABOLISM
-Metabolism is the sum of all the chemical reactions occurring in living cells.
-Exported organic matter = gametes, milk, mucous, hair, etc., but also urea, and others,
-External work = moving the body, or moving objects outside the body, via skeletal
muscle contraction
-Internal work = moving materials within the body, e.g., blood, ions
How does energy flow through animals?
-All animals are chemoheterotrophic by ingesting energy and oxidizing it and this is how
they derive energy from their environment.
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-We need to ingest
chemical energy, that
energy has two fates,
that energy could be
absorbed through the
gut wall, or it doesn't get
absorbed and gets
expelled as fecal
chemical energy.
What determines whether the
energy that we consumed gets
absorbed or not?
-The type of food that we
eat determines whether
they get absorbed or
not.
Eg. nectar from flower or meat, are easy foods to digest. Largely contain simple
molecules, able to break down the chemical material by the digestive system. The
percentages represented in the picture above show the absorbing efficiencies of
that specific food.
-Only 10-70% of cellulose we eat can’t be absorbed because cellulose is very resistant to
being broken down by the human digestive system so the cellulose ends up in the feces
still in intact.
-The food that the animal eats determines their digestive tracts.
-The digestive system of the cow (or herbivores) are complex to allow the cellulose more
time to break down and absorb that energy.
-The herbivore’s stomach (or digestive system) is more complex, includes or is called the
fermentation chamber, which employs the assistance of bacteria. A place where
bacteria can be kept to help break down the food.
-In herbivores, some part of their digestive tract will be modified to serve as a so called
fermentation chamber. Which means by one way, as a herbivore you can try to break
down some of the cellulose you’re eating is to employ the assistance of bacteria
because bacteria are good at degrading some of the hard to digest food molecules.
-Some herbivores don't always have the stomach as the fermentation chamber.
What happens to the absorbed energy then?
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