Untitled Quiz

Ecology Stories

• Ecology is the study of interactions between organisms and their environment, focusing on processes that shape ecosystems.
• Forest dynamics are the natural changes in forest structure and composition over time, influenced by ecological processes like succession, disturbances, and species interactions. Drivers of these include CO2 levels, temperature, and water potential deficit (VPD). Demographic drivers also play a role, such as drought, land-use changes, wildfires, wind, and insect outbreaks.

Key Processes

• Succession: Forests develop from pioneer species to mature ecosystems.
• Disturbances: Events like storms, fires, or human activity reset forest stages.
• Wildlife Interactions: Animals play roles as pollinators, seed dispersers, and herbivores.

Importance of Forest Dynamics

• Maintains biodiversity
• Supports ecosystem services (e.g., carbon storage, water regulation).

Interconnections Between Processes

• Succession sets the stage for plant and animal communities.
• Pollination ensures plant reproduction, contributing to forest growth.
• Dispersal spreads seeds, enabling succession and forest regeneration.
• Forest dynamics encompass all these processes, shaping ecosystems over time.

Succession

• Succession is the gradual and natural process by which ecosystems change and develop over time.
• Primary succession occurs in lifeless areas like volcanic lava or glaciers.
• Secondary succession occurs in areas where life existed but was disturbed (e.g., after a forest fire). Different plant species, like Xylocarpus etc occupy different zones within the area, from landward to seaward.

Factors Influencing Succession

• Site conditions (e.g., soil, climate).
• Species interactions (e.g., competition, facilitation).
• External events (e.g., erosion, natural disasters).

Pollination

• Pollination is a crucial biological process in plant life cycles enabling fertilization and the production of seeds and fruits.
• It involves transferring pollen grains from the male part (anther) of a flower to the female part (stigma) of the same or a different flower.

Steps in Pollination Process

• Pollen Production: Pollen grains (containing male gametes) are produced in the anther.
• Pollen transfer: Pollen is transferred to the stigma, often by agents like wind, water, or animals (e.g., bees, butterflies, birds).
• Pollen Germination: The pollen germinates into a tube, reaching the ovule.
• Fertilization: Male gametes travel through the tube to the ovule, resulting in seed formation.

Importance of Pollination

• Reproduction: Essential for plant fertilization, seed, and fruit production.
• Genetic diversity: Promotes genetic variation in plants, crucial for adaptability and survival.
• Ecosystem Services: Supports biodiversity and is critical for the production of crops.

Types of Pollination

• Self-Pollination: Pollen is transferred within the same flower or between flowers of the same plant.
• Cross-Pollination: Pollen is transferred between flowers of different plants, often assisted by factors like insects, wind, or water.

Pollination Agents

• Abiotic factors: Wind, water
• Biotic factors: Birds, insects, bats

Biotic Pollination

• Plants that require pollinators for reproduction, from insects to vertebrates.
• Entomophily (insect pollination); Zoophily (pollination by vertebrates); Ornithophily (bird pollination); Chiroperophily (bat pollination); and Anthropophily (human pollination).

Factors Affecting Pollination

• Plants: Floral display size, flowering plant density, nectar-sugar concentration, flowering plant adaptations
• Weather: Lack of pollinators, domesticated pollinators, light intensity, and humidity
• External factors: Insecticides, temperature, wind speed

Cross Pollination & Self Pollination

• Cross-pollination involves the transfer of pollen between different flowers.
• Self-pollination involves the transfer of pollen within the same flower or between flowers of the same plant.

Seeds

• Seeds: Fertilized ovules containing an embryo and stored food.
• Key unit of plant reproduction.
• Important in tropical ecology due to being the foundation, maintaining biodiversity and ecosystem function.

Seed Adaptations in Tropical Conditions

• Thick seed coat: protects against harsh conditions, predators, and pathogens.
• Dormancy: Delays germination until favorable conditions arise.
• Nutrient storage: Provides energy for seedling growth.

Seed Size and Shape

• Small seeds: Often wind-dispersed, numerous, and short-lived
• Large seeds: Typically animal-dispersed, fewer in number, and longer-lived.

Types of Seeds in Tropical Ecosystems

• Orthodox seeds: Tolerate drying and freezing
• Recalcitrant seeds: Cannot tolerate drying or freezing. Characteristic of many tropical tree species.

Seed Dispersal

• Abiotic factors: Wind (small, lightweight seeds with wings or hairs); water (seeds with buoyant structures).
• Biotic factors: Endozoochory (ingestion and dispersal in feces); epizoochory (attachment to animal fur or feathers). Ant dispersal (small seeds with elaiosomes).

Importance of Seeds in Tropical Ecology

• Regeneration: Essential for the establishment of new forests.
• Biodiversity maintenance: Diverse seed dispersal mechanisms contribute to genetic diversity.
• Ecosystem services: Provide food for animals, contribute to soil fertility, and support carbon sequestration.
• Human use: Source of food, medicine, and valuable products.