Class Notes (1,200,000)
CA (650,000)
UTSG (50,000)
BIO (2,000)
BIO120H1 (1,000)

lecture note

Course Code
Ingrid L.Stefanovic

of 2
L04- BIO 120
Making hay (literlly) slide:
Slide 17- a plants a relationship with animals is completely different from the
relationship animals hre with plants, because plants make their own food.
18- having big thin flats is a good thing, for harvesting light and pulling out
Co2 from the air.
19- when the stomta are open, only then can plants phtosynthesize.
20- if aplant is in danger of overheating, it opens its stomata
26- variation in leaf shape
middle on has cut out from the side, and the first leaf has cuts that are deep
called sines. Why does aving a bigger sunis matter? Shedding heat to revent
overheating, its so plants can get rid of extra heat.
28- difference between two types of flows
30- laminar flow also effects animalsthe rabbits ears in the second picture,
interrupt air flow, and so eddies is formed.
33 + 34- most common plants, doing a couple of things to prevent water loss.
Needs no laves, can photosynthesize from stick. But does produce leave, but
they are tiny ( called microphylyy). This is an example of adaptaion, so that
the leaves dont overheat.
35- extreme staretgy: losing leaves entirely. Most cacti do this, have flat pads.
They are not leaves, they are modified stems. They keep a lot of water in
tissue. Plants that grow in areas that are moist dont store water in tissues,
because the ground can store water, as the ground does get moist.
For cacti to store water, they must get it from somewhere. Cactis tend
to have really long roots ( see slide 37)
39- catci has rib like [pleated structure] structure, it expands in diameter. It
is not a rigid cylinder, and so it can hold more water as it can expand.
Therefore, they can absorb a tremenodous amount of water [800L]. way to
remember these: david grundman he and his buddy shot cactis until they
fell over, he shot a couple over, an so stood underneath one and shoot it, but it
fell down [ because it was SO HEAVY from the water] and killed him.
40- Nurse tree effect- though cactis are beautifully adapted, there is still some
stress. Nurse-tree effect you usually fins these cactis in shady areas under
another plant, where its not quite so hot or stressful.
41- since it is stressful in deserts for small cactis.
42- plants called epiphytes, grow up on a branch of a tree or the trunk of a
tree. Grow ATTACHED TO ANOTHER PLANT. They end to be best
represent in the tropics, where it rains quite frequently This is important,
because ethy dont have roots in soil and so cannot withstand dry + hot
these plants are in danger of having there tissues drying out.
The pineapple family are epiphytes
Demos: sponge epiphytes takes in water during wet days for dry days.
47- paradox