Unit 8

Question 1

Organisms ability to maintain homeostasis by responding to changes in internal + external environment

Answer 1

Regulation

Question 2

Tropism

Answer 2

Responses to environmental stimuli that result in plants growing toward or away from the stimulus

Question 3

Phototropism

Answer 3

Stimulus is light: photoreceptors on tip of shoot detect light → auxin builds up on side without light wich causes elongation → stem bends towards light

Question 4

Geotropism

Answer 4

Stimulus is gravity

Question 5

Hydrotropism

Answer 5

Stimulus is water

Question 6

Thigmotropism

Answer 6

Stimulus is touch

Question 7

Photoperiodism

Answer 7

Response to relative length of light + dark in 24 hour period:

Question 8

Long night plants (short day plants)

Answer 8

Require a dark period longer than critical length

Question 9

Short night plants (long day)

Answer 9

Require a dark period shorter than critical length

Question 10

A flash of light during the dark period will:

Answer 10

Reset the # of hours of darkness to zero

Question 11

Phytochromes

Answer 11

Photoreceptors that change conformation in light: in light - Pfr > Pr, in dark- Pr > Pfr (fr-far red light is absorbed, r-red light is absorbed)

Question 12

If far red light follows a flash of red light interrupting a dark period…

Answer 12

The reset is canceled and the original darkness period is restored

Question 14

Stomata

Answer 14

Holes in leaf that allow for gas exchange (O2, CO2, H2O)

Question 15

On hot + dry days plants… their stomata

Answer 15

Close to prevent excess water loss - but this decreases photosynthesis

Question 16

Affect on humidity on rate of transpiration

Answer 16

Decreases transpiration

Question 17

Affect of wind on transpiration

Answer 17

Increases transpiration

Question 18

Affect of temp. On transpiration

Answer 18

Increases transpiration

Question 19

Factors that reduce water loss (4)

Answer 19

Stomata concentrated on bottom of leaves, cuticle, reduced leaf surface area, reduced #of stomata

Question 20

Plants response to water deficit (4)

Answer 20

Closing stomata, inhibit leaf growth, change leaf shape, increase root growth

Question 21

Population density

Answer 21

Of individuals per unit of volume

Question 22

Dispersion

Answer 22

Spacing of individuals in a population (clumped, uniform, random)

Question 23

3 typical survivorship curves

Answer 23

Type 1: high death in old age, type 2: constant mortality rate, type 3: high death early on

Question 24

Density dependent limiting factors (6)

Answer 24

Parasites, intra-specific competition, predation, crowding, buildup of toxins, disease,

Question 25

Density independent limiting factors (3)

Answer 25

Weather, natural disasters, extremes of climate

Question 26

Opportunistic species that can quickly colonize a habitat

Answer 26

R-selected populations

Question 28

Equilibrium species that typically are at or near carrying capacity in a stable environment

Answer 28

K-selected population

Question 29

Symbiosis

Answer 29

2 species living together

Question 30

Mutualism

Answer 30

Both species benefit

Question 31

Commensalism

Answer 31

One species benefits, the other is neither helped nor harmed

Question 32

Parasitism

Answer 32

A parasite benefits by living in or on the host which is harmed as a result

Question 33

Reciprocal evolutionary adaptions in a populations

Answer 33

coevolution

Question 34

Mallerian mimicry

Answer 34

Several species with the same defense mechanism share the same coloration patter

Question 35

Batesian mimicry

Answer 35

Animal that lacks a defense mechanism was the warning coloration of an animal that has a defense mechanism

Question 37

Niche

Answer 37

Populations rote in the ecosystem

Question 38

Ecological succession

Answer 38

Change in plant community over time

Question 39

Primary succession

Answer 39

Occurs in a location where no life or soil is present