chapter 4

Question 1

Effects of Gravity

Answer 1

animals
-internal skeleton
-external skeleton
fungi
-cell walls of chitin
plants
-cell walls of cellulose

Question 2

Land Constraints

Answer 2

gravity
nutrient acquisition
dessication
thermoregulation

Question 3

Soil

Answer 3

basis of terrestrial ecosystem
medium for plant growth
initial recipient of water, controlling its fate
recycling system
a habitat
both abiotic and biotic
has depth, length and width

Question 4

Soil Definition

Answer 4

solid substrate of terrestrial communities resulting from the interaction of weather and biological activities with the underlying geological formation

Question 5

Soil Layers

Answer 5

Organic Layer
Topsoil
Subsoil
Unconsolidated Material

Question 6

Organic Layer

Answer 6

O Horizon
-dominated by organic material
-consists of undecomposed or partially decomposed plant materials such as dead leaves

Question 7

Topsoil

Answer 7

A Horizon
-largely mineral soil developed from parent material
-organic matter leached from above gives the horizon a distinctive dark color

Question 8

Subsoil

Answer 8

B Horizon
-accumulation of mineral particles such as clay and salts leached from topsoil
-distinguished based on color, structure, and kind of material accumulated from leaching

Question 9

Unconsolidated Material

Answer 9

C Horizon
-derived from the original parent material from which the soil developed

Question 10

Weathering

Answer 10

how soils are formed
-process whereby parent rock is broken down by physical and chemical processes

Question 11

Mechanical Weathering

Answer 11

-results from the interaction of water due to it seeping into crevices
-results from temperature, water freezing and expanding which can break the rock into smaller pieces
-results from wind scouring the surface with dust and sand
-results from organisms’ plant roots splitting rocks

Question 12

Chemical Weathering

Answer 12

chemically alters and breaks down rock and minerals
-soil organisms activities produce water, oxygen and acids
-organism material from dead organisms or shed tissues

Question 13

Five Interrelated Factors for Soil Formation

Answer 13

-parent material
-biotic factors
-climate
-topography
-time

Question 14

Water Potential

Answer 14

capacity to perform work
dependent on free energy content

Question 15

Water Movement

Answer 15

water potential pie
-reduction in water potential due to dissolved substances
water potential m
-reduction in water potential due to Matric Forces
water potential p
-reduction in water potential due to negative pressure created by transpiration and changed in turgor pressure

-as long as water potential in plants is less than water potential in soil water flows from the soil to the plant

Question 16

Field Capacity

Answer 16

water held within the soil by internal capillary forces
varies with texture
lower in coarse soils
higher in fine soils

Question 17

Wilting Point

Answer 17

soil moisture level below which plants can no longer extract water
water present but held too tightly

Question 18

Soil Texture/Classification

Answer 18

Sand- 0.05 to 2.0 mm which is easy to see
Silt- 0.002 to 0.05 mm which is difficult to see with the naked eye
Clay-less than 0.002 mm which is microscopic

Question 19

Ideal Soil

Answer 19

50% soil particles, 50% pore space
-pore space includes spaces within and between soil particles
-old root channels
-animal burrows

Question 20

Clay and Humus

Answer 20

-influence nutrient content
-ability to hold minerals
-attraction to micelle influence leached mineral
-potassium and calcium ions leach easily

Question 21

Soil pH

Answer 21

-higher H concentration increases leaching

Question 22

Water Transpiration

Answer 22

-water vapor lost from leaves
-water moves to equalize osmotic pressure

Question 23

Transpirational Pull

Answer 23

-force or tension in leaves due to transpiration
-affects water column in Xylem
-acts as lower atmospheric pressure

Question 24

Water Movements in Plants

Answer 24

-movement goes from areas of higher water potential to lower potential

Question 25

Control of Transpiration

Answer 25

water loss controlled by stomata

Question 26

C3 Photosynthesis

Answer 26

-used by most plants and algae
-CO2 + ribulose biphosphate (5 carbon sugar)
-produces phosphoglyceric acid (3 carbon acid)
-catalyzed by rubisco which is also an oxygenase
-results in photorespiration- the release of CO2

Question 27

C4 Photosynthesis

Answer 27

-reduce internal CO2 concentrations
-increase rate of CO2 diffusion inward
-need fewer stomata open which conserves water
-assimilate carbon in 2 biochemical processes

Question 28

CAM Photosynthesis

Answer 28

-Crassulacean Acid Metabolism
-limited to succulent plants in arid and semi arid environments
-carbon fixation takes place at night which reduced water loss
-low rates of photosynthesis
-extremely high rates of water use efficiency

Question 29

Darwins Theory of Natural Selection

Answer 29

-organisms make offspring that look like them
-chance variation between individuals
-more offsprings are produced each generation that can survive
-some individuals because of physical or behavioral traits have a higher chance of surviving than others in the same population

Question 30

Temporal Variation

Answer 30

description of how environmental conditions change over time
-rate and intensity important factors
-history influences the evolution

Question 31

Spatial Variation

Answer 31

-main influence on distributions
-allows adaptive radiation

Question 32

Phenotypic Plasticity

Answer 32

ability of one genotype to give rise to different phenotypes under different environmental conditions