Topic 7 -Plant Adaptations

Question 1

Plants have evolved a variety of adaptations to successfully grow reproduce and survive across the entire range of environmental conditions on earth which are

Answer 1

Light
temperature
water availability

Question 2

Photosynthesis takes place in specialize cells called

Answer 2

Mesophyll cells in the leaf

Question 3

Net photosynthesis equals

Answer 3

Photosynthesis minus respiration

Carbon uptake minus carbon loss

Question 4

CO2 diffuses into the leaf through openings in the surface of the leaf called

Answer 4

Stomata

Question 5

As CO2 diffuses into the leaf water diffuses

Answer 5

Out of the leaf (transpiration)

Question 6

Tree top (direct sunlight)

_________, ________ leaves

________ water loss in direct sunlight

Answer 6

Smaller, thicker

Reduces

Question 7

Tree bottom (shade)

________, ________ leaves

_______ photosynthetic rate in shade

Answer 7

Larger, thinner

Increase

Question 8

In many environments different leaf ____ Can be beneficial

Leaves in arid environments minimize ________ by angling leaves away from the sun

Answer 8

Angles

Evaporation

Question 9

Shade tolerant plants have

Answer 9

Lower production of Rubisco in leaf tissue so they do not expend energy producing high amounts of Rubisco

Less photosynthesis

Question 10

How do shade tolerant plants compensate

Answer 10

Higher production of chlorophyll

Higher leaf surface area

Higher growth of leaves than roots

Question 11

Shade intolerant plants have a ______ growth rates under sunlight but ______ growth rates in shade

Answer 11

High, low

Question 12

Shade tolerant plants grow ______ under sunlight and shade due to limited rubisco numbers

Answer 12

Similarly

Question 13

Mountain Avens are flowers that track the

Answer 13

Movement of the sun

Parabolic formation of pedals concentrate light to maintain a constant temperature of 25°C

Question 14

A maximum rate of photosynthesis and respiration occur at

Answer 14

Different points as temperature rises above zero

Question 15

To maintain optimal levels of photosynthesis a leaf must exchange excess heat with the surrounding environment by

Answer 15

Convection

conduction (radiation)

evaporation (transpiration)

Question 16

Heat loss by convection

Answer 16

Transfer of heat to a moving fluid body example wind

Question 17

Heat loss by conduction

Answer 17

Keep moving from a warmer to a cooler body

Question 18

Heat loss by evaporation

Answer 18

Evaporation causes a loss of heat energy and temperatures drop due to evaporated cooling

Question 19

What is pubescence

Answer 19

Small light coloured hairs that line a leafs surface and reflect

Less Heat obtained from solar radiation

Creates an insulated boundary later

Question 20

What accumulation of compounds prevent ice formation

Answer 20

Sugars and amino acids (proline) and other solutes

Question 21

Super cooling

Answer 21

Special antifreeze proteins preventing ice crystal growth allowing plants to survive up to -35°C

Present in floral and shoot buds

Question 22

Frost hardening

Answer 22

Changes composition of membranes allowing cells to export water and ice to form between cells instead of within

Survives up to -50°C

Question 23

How do deciduous trees survive in winter

Answer 23

Adaptive loss of leaves as the temperature drops in the fall months

Question 24

What do plants do when the atmosphere humidity and soil moisture levels are low

Answer 24

Close stomata

Question 25

How do plants prevent water loss for short time scales

Answer 25

Close stomata during the hottest part of the day and also curl or wilt leaves to reduce surface area

Question 26

How do plants manage water loss or uptake during moderate time scales

Answer 26

For wet conditions increase leave tissue and decrease root and shoot

For dry conditions increase root tissue decrease leave and shoot

Question 27

Long time scale leaf morphology adaptations to dry conditions

Answer 27

Smaller and thicker leaves

smaller stomata

cover leaves in wax resin or a little hairs

Alter Net photosynthesis pathways such as C4 photosynthesis and CAM photosynthesis

Question 28

Why is the alternate photosynthesis pathways beneficial

Answer 28

Reduce O2 binding by RuBisCO

concentrate CO2 to RuBisCO

high much higher maximum rate of photosynthesis

Plant loses less water per unit of photosynthetic product, Greater water use efficiency