bio review video 1 transcript Flashcards
(27 cards)
What do all plants have in common in their life cycle?
Alternation of generations: diploid sporophytes make haploid spores → gametophytes → gametes → fertilization.
What are gymnosperms
Gymnosperms produce seeds in cones
What are angiosperms
angiosperms produce seeds inside fruits formed from ovaries.
Where is the sperm of a flowering plant located?
Inside the pollen tube, which is the male gametophyte.
What structure in corn receives pollen?
The pistil (silk); each connects to an ovule that becomes a seed.
What are annual, biennial, and perennial plants?
Annual = 1-year life cycle; biennial = 2-year; perennial = lives many years.
What characterizes r-selected species?
High fecundity, little to no parental care, short lifespan (e.g., dandelions, blue crabs).
What characterizes K-selected species?
Low fecundity, high parental care, long lifespan (e.g., seahorses, coconuts).
Are most crops r- or K-selected?
R-selected — many offspring (seeds), low investment.
Why do monocultures like wheat fields indicate high disturbance?
They replace diverse ecosystems with one species and often require herbicide use (e.g., glyphosate).
What is a hermaphrodite?
An organism with both male and female reproductive structures (e.g., earthworms).
What is sequential hermaphroditism?
The ability to switch between sexes (e.g., barnacles, wrasse fish).
What is parthenogenesis?
Asexual reproduction without fertilization — offspring are clones (e.g., some sharks, daphnia).
Why might sequential hermaphroditism be adaptive?
Increases fitness when one sex has better reproductive success at a given time.
What causes nutrient leaching in soil?
Nitrate, phosphate, sulfate (all negative ions) repelled by negatively charged sandy soil particles.
How do plants reduce nutrient loss?
They release protons (H⁺) to attract nutrients but risk acidifying the soil.
What type of soil helps retain nutrients?
Iron-rich Piedmont soils with positive charges bind negative ions more effectively.
What does nitrate provide to plants and animals?
Nitrogen for amino acids and proteins.
Why is the nitrogen cycle important?
Supplies essential nitrogen for amino acids and proteins in plants and animals.
What is leaching?
Movement of dissolved nutrients away from roots via water flow.
What is unique about the phosphorus cycle?
Long-term cycle tied to rock weathering and sediment — slow and geologic.
What biome cycles the most oxygen per area?
Tropical rainforests — high productivity and oxygen cycling.
What is primary productivity?
total rate of photosynthesis in an ecosystem over time.
What is net primary productivity (NPP)
Energy available to the next trophic level after respiration losses.
