Plant Ecology, Morphology, Flowers, Seeds, Stems, and Leaves Review

Comprehensive flashcards covering Plant Ecology, Flowers, Seeds, Stems, and Leaves based on course lecture slides.

How is population density calculated?

It is calculated as $\frac{\text{number of individuals}}{\text{unit volume}}$.

What percentage of the Earth's water is held in oceans, rivers, and lakes?

$98\%$ of Earth's water is contained in oceans, rivers, and lakes.

What percentage of water pumped from underground aquifers is used for irrigation, industry, and homes?

Irrigation uses $70\%$, industry uses $20\%$, and homes use $10\%$.

What percentage of the Earth's atmosphere consists of carbon dioxide ($\text{CO}_2$)?

$\text{CO}_2$ accounts for $0.040\%$ of the atmosphere.

What proportion of replaced carbon dioxide ($\text{CO}_2$) during respiration can be produced by bacteria and fungi?

As much as $90\%$ of replaced $\text{CO}_2$ is produced by bacteria and fungi.

What is allelopathy?

The production of chemicals by plants that inhibit the growth of other plants.

What are phytoalexins?

Chemicals produced by plants that kill or inhibit disease fungi or bacteria.

What effect does a mutualistic relationship with mycorrhizal fungi have on a plant's root system?

Mycorrhizal fungi expand the root zone of the plant, whereas plants without mycorrhizae have a limited root zone.

What is the key distinction between primary succession and secondary succession regarding the soil?

Primary succession involves the initial formation of soil on bare rocks or lava, whereas secondary succession occurs where soil is already present.

What is a climax community?

A stable plant community that has reached an equilibrium after succession.

In what ways do natural fires benefit forest and grassland ecosystems?

Fires convert dead organic matter into mineral-rich ash, expose pyrophytic seeds to fire, and encourage nitrogen-fixing bacteria.

How do $C_3$ and $C_4$ plants differ in response to increased atmospheric $\text{CO}_2$ levels?

$C_3$ plants increase growth with increased $\text{CO}_2$ levels, while $C_4$ plants do not.

What is trophic efficiency in an ecosystem energy pyramid?

The percentage of available energy actually transferred from one trophic level to the next.

What are the two main functions of a flower?

1) Reproduction and 2) Production of seeds.

Which three structures comprise the female component (pistil) of a flower?

The stigma, style, and ovary.

Into what structure does a flower ovary develop after fertilization?

The ovary develops into a fruit.

What components make up the male reproductive unit (stamen) of a flower?

An anther and a filament that supports the anther.

What is the collective term for the whorl of sepals, and what is its main function?

The calyx, which protects the flower while it is in bud.

What is the collective term for petals, and what term describes the combined calyx and corolla?

Petals are collectively called the corolla, and together with the calyx, they form the perianth.

What is an inflorescence?

A group or cluster of flowers attached to a plant.

What is the difference between monoecious and dioecious plant species?

Monoecious plants have both male and female reproductive parts on one plant/flower, whereas dioecious plants have distinct male and female flowers on separate plants.

What are the three distinct regions of a fruit pericarp as shown in a peach?

The exocarp (outer skin), mesocarp (fleshy middle tissue), and endocarp (inner boundary around the seed).

What defines a drupe fruit?

A simple fleshy fruit containing a single seed enclosed by a hard, stony endocarp or pit.

What is the difference between a pepo and a hesperidium?

A pepo is a berry with a relatively thick rind (e.g., pumpkins, cucumbers), while a hesperidium is a berry with a leathery skin containing oils (e.g., oranges, lemons).

What floral tissue forms the bulk of the fleshy edible part in pome fruits like apples and pears?

An enlarged floral tube or receptacle that grows up and around the ovary.

How do seed scarification and after-ripening differ?

Scarification is the artificial breaking of seed coat dormancy (e.g., via mechanical abrasion), whereas after-ripening is the process in which an embryo matures from a few cells before the seed can germinate.

What are the definitions of epicotyl and hypocotyl in a seed embryo?

Epicotyl is the stem portion above cotyledon attachment, and hypocotyl is the stem portion below cotyledon attachment.

What are the four primary functions of a plant stem?

1) Support, 2) Transport, 3) Producing food, and 4) Producing more stems.

What are two distinct physical characteristics of meristematic cells?

Meristematic cells have thin cell walls and dense cytoplasm.

Which lateral meristem produces secondary xylem toward the center and secondary phloem toward the surface?

The vascular cambium.

What structures on a dormant woody twig mark where leaves were attached and where vascular tissues connected?

Leaf scars mark former leaf attachments, and bundle scars within leaf scars mark the former food and water conducting tissue.

What plant tissue constitutes botanical wood?

Secondary xylem.

How do monocot stems differ from dicot stems regarding secondary vascular growth?

Monocot stems lack both vascular cambium and cork cambium, so they produce no secondary vascular tissues or cork, having discrete vascular bundles scattered throughout.

How do rhizomes differ from runners or stolons?

Rhizomes are horizontal stems that grow below-ground, while runners and stolons grow above or just beneath the soil surface.

How does an Irish potato tuber differ morphologically from a sweet potato?

An Irish potato is a modified stem (tuber) with eyes that serve as nodes, whereas a sweet potato is a swollen storage root that develops adventitious buds across its surface.

What are the three primary functions of a leaf?

1) Photosynthesis, 2) Storage, and 3) Transpiration.

How do guard cells open and close a stoma?

Guard cells inflate (become turgid with water) to open the stoma and deflate to close the stoma.

How does leaf venation differ between monocots and dicots?

Monocots feature parallel venation where primary veins run parallel, while dicots feature netted venation where primary veins diverge in various branching patterns.

What are the three main types of leaf phyllotaxy arrangements?

Alternate (one leaf per node), Opposite (two leaves per node), and Whorled (three or more leaves per node).

What key morphological features distinguish monocot seeds and seedlings from dicot seeds and seedlings?

Monocots have a single cotyledon, parallel leaf veins, and fibrous roots; dicots have two cotyledons, netlike leaf veins, and a tap root system.