essay on tropical rainforest biomes Flashcards
(26 cards)
What is a tropical rainforest biome?
A hot, humid ecosystem near the equator with high rainfall (>2000 mm/year), year-round warm temperatures, high biodiversity, and nutrient-poor soils.
What is a plant adaptation?
A heritable trait that improves a plant’s ability to survive and reproduce in a specific environment.
What are physiological responses in plants?
Short-term changes in function (e.g. stomatal closure) in response to environmental stimuli like moisture or light levels.
What are the key environmental pressures in tropical rainforests?
Low light in the understorey, intense competition, poor nutrient availability, constant high rainfall, and stable warm temperatures.
What are drip tips and what is their function?
Pointed leaf tips that shed excess water efficiently, preventing fungal growth; common in Ficus and Calathea.
What is the function of buttress roots?
Stabilize tall trees in shallow, nutrient-poor soils. Example: Ceiba pentandra (kapok tree).
Why do some rainforest plants have large leaves?
To capture as much light as possible in the shaded understorey. Example: Monstera, Alocasia.
What are epiphytes and how are they adapted?
Plants that grow on other plants to access light without soil contact. They often have aerial roots and water-storing structures. Examples: orchids, bromeliads.
What are prop roots and which plants use them?
Roots that grow from stems to support the plant and access air in waterlogged soils. Example: Pandanus and some mangroves.
How do tropical plants cope with nutrient-poor soils?
Through shallow root systems that absorb fast-released nutrients from decomposing litter and by forming mycorrhizal associations.
What is a mycorrhizal association?
A mutualistic relationship between fungi and plant roots that enhances nutrient uptake—especially phosphorus.
What is CAM photosynthesis and which rainforest plants use it?
A photosynthetic pathway that allows stomata to close during the day to reduce water loss—common in epiphytic orchids and bromeliads.
How do plants compete for light in the rainforest?
With vertical stratification (e.g., emergents, canopy, understorey) and fast growth when gaps open (gap dynamics). Example: Cecropia species.
What is gap dynamics and why is it important?
The process where canopy treefalls create light gaps; fast-growing species like Cecropia rapidly colonize these.
How are seeds typically dispersed in tropical rainforests?
Mostly by animals (zoochory), but also by wind or water. Example: monkeys disperse Ficus seeds.
What is mast seeding and which plants use it?
Occasional, synchronized seed production to overwhelm seed predators. Used by Dipterocarp trees in Southeast Asia.
Name an adaptation used by Ceiba pentandra in the Amazon.
It uses large buttress roots to stabilize its tall trunk in poor soils.
How is Bertholletia excelsa (Brazil nut) adapted to rainforest conditions?
Forms mutualistic relationships with fungi and relies on specific pollinators and seed dispersers.
Give an example of a rainforest epiphyte and its adaptation.
Orchids use aerial roots to absorb moisture from the air and anchor to canopy trees for light access.
What type of strategy do Dipterocarp trees in Borneo use for reproduction?
Mast flowering and seed production to ensure some seeds survive despite predators.
What does Grime’s CSR theory say about rainforest plants?
They tend toward Competitor (C) strategies—maximizing growth in stable, resource-rich environments.
How did Whittaker (1975) classify rainforests?
As high productivity, high biodiversity biomes with low seasonality.
What did Richards (1996) contribute to rainforest ecology?
A detailed account of tropical rainforest structure and adaptations in his book The Tropical Rainforest.
What is the significance of Primack & Corlett (2005)?
Provided comparative biogeographical studies of tropical rainforests across continents.
