Lab 2: Plant Cells, Tissues, & Eco-Physiological Adapations

Observation

The notice of a trend or phenomenon

• Example: When I accidentally got some vinegar on my herb garden, some of the plants died

Null Hypothesis

The hypothesis that there is no difference or similarity between groups and any observed relationship is due to random chance or experimental error

• Example: The plants died because of something other than the acidity of the vinegar

Alternative Hypothesis

An explanation for the cause of an observation

• Example: vinegar kills plants because it’s acidic

Prediction

A testable statement of what will happen in the experiment if the alternative hypothesis is true

• If [alternative hypothesis is true], then [X should be the result of Y]

• Mentions the dependent variable collected

Designing and Running an Experiment

Providing evidence for or against the hypothesis

Statistical Analysis and Conclusions and Repeat

• Analysis: Are your results representing a true relationship or could they be due to random chance?

• Conclusion: what do those results mean?

• Repeat: Based on the findings of the initial experiment, what new hypothesis can you test?

Control Group

A group of experimental subjects that is not exposed to the treatment being investigated so that it can be compared with experimental groups that are exposed to the treatment, thus is a standard for comparison

Explanatory Variable for Lab 2

What concentrations of fertilizers (our treatment) should we use?

Response Variable for Lab 2

What response are we measuring in the plants? Is it categorical or continuous?

• Example: we’re measuring how tall the plant grows

Fertilizer Experiment

Investigating how different concentrations of fertilizer effect plant growth and development

• Germinating radish seeds in ¼x, 1x, and 10x the recommended amount of Miracle Grow Fertilizer

Monocot vs. Dicot Root Shape

• Monocot: fibrous root system

  • Many thin roots spread out in multiple directions

  • Dense, shallow network

• Dicot: tap root system

  • One thick main root that grows downward

  • Smaller lateral roots that branch off

  • Can grow deeper into the soil

Monocot vs Dicot: Root Cross Section

• Monocot: vascular bundles of xylem and phloem occur in the central ring

  • Has a central “pith” of normal cells

• Dicot: vascular bundles occur in the central cross (x-shape pattern)

  • Xylem forms the “X”

  • Phloem surrounds/sits between the “X”

  • Organized pattern that allows for secondary growth

Monocot vs Dicot Leaf Venation

• Monocot: parallel veins

  • Veins represent vascular bundles

  • Ex: grass or maize

• Dicot: branching veins

  • Often one large vein with smaller ones branching out/interconnecting

Monocot vs. Dicot Stem Cross Section

• Monocot: scattered vascular bundles

  • Do not have a distinct pattern

• Dicot: vascular bundles occur in an outer ring

  • Xylem is always on the inside (the vascular bundles face in)

  • Very organized/patterned (layering = important for secondary growth)

Artic Tundra

• Low productivity

• Low species diversity

• Low aboveground biomass

• Permafrost (soil can be permanently frozen)

• Dominant vegetation: low plants, trees are absent

  • Also low animal diversity, but abundance of insects

• Average temp: ~5 C

Boreal Forest

• Low productivity/exceptionally low species diversity b/c of low temperature + low precipitation

• Dominated by pines, spruce, fir, larch trees

• High aboveground biomass

• Low structural diversity

• Average temp: ~15 C

Temperate Forest

• Moderate productivity and diversity

  • Temperatures do not support year-round photosynthesis

• Dominated by deciduous tress (leafless in winter) and needle-leaved evergreens

• Average temp: ~25 C

Temperatre Grassland

• Lower productivity than forests

• Grassland soils are often highly fertile

• Dominated by grasslands b/c of dry conditions (too dry for trees)

• Extremely dense plant life above and belowground

• Average temp": ~30 C

Desert and Dry Shrubland

• Extreme temperatures

• Low moisture

• Extremely low productivity

• Cacti (or plants with spines or leaves w/ a thick/waxy coating to minimize water loss)

• Slow growth year-round

• Average temp: ~35 C

Tropical Wet Forest

• Favorable year-round growing conditions

• High aboveground biomass

• High species diversity and productivity

• Average temp: ~22 C

Cloud Forest (Poly Plant Conservatory)

• Observed abundant factors: moisture (fog + cool humidity), stable climate

• Observed limiting factors: sunlight and nutrient-rich soil

• Growth characteristics: ability to absorb water from the air, broad leaves for capturing sunlight, shallow root systems to get surface nutrients

Tropical Forest (Poly Plant Conservatory)

• Observed abundant factors: rainfall, warm temperatures (hot/humid), biodiversity

• Observed limiting factors: sunlight at the forest floor, soil nutrients

• Growth characteristics: fast growth rates (competing for light), symbiotic relationships

Arid Environment (Poly Plant Conservatory)

• Observed abundant factors: sunlight, open space/low competition, mineral abundance in soil

• Observed limiting factors: limited water, extreme temperatures, poor nutrient soil

• Growth characteristics: adaptations to water conservation, efficient water storage, rapid life cycles following rainfall