Correct option is C
Primary successional species are the first organisms to colonize a newly formed or disturbed environment where no previous life existed (e.g., volcanic islands, newly exposed rock surfaces). These species are typically r-strategists, characterized by high reproductive rates, low parental care, and high early mortality, which corresponds to a Type III survivorship curve.
Characteristics of Primary Successional Species:
- High fecundity (many offspring).
- Rapid dispersal and colonization.
- Short lifespan with high mortality at early life stages.
- Can tolerate extreme or nutrient-poor environments.
- Example: Lichens, mosses, some grasses, pioneer plants like fireweed.
Information Booster
Primary vs. Secondary Succession:
- Primary succession: Occurs in completely barren areas (e.g., lava flows, glacial retreats).
- Secondary succession: Occurs in previously inhabited but disturbed areas (e.g., after forest fires).
Survivorship Curves:
- Type I (Low early mortality, high survival): Found in K-selected species (e.g., humans, elephants).
- Type II (Constant mortality rate): Found in birds, reptiles, and rodents.
- Type III (High juvenile mortality, few survivors): Found in r-selected species (e.g., fish, amphibians, and pioneer plants).
Role in Ecosystems:
- Primary successional species prepare the environment for later species by building soil and improving conditions.
- Lichens break down rock into soil, facilitating plant colonization.
Additional Information
Option (1) These species do not follow specific survivorship curves (Incorrect):
- Primary successional species do follow Type III survivorship curves.
Option (2) These species show Type II survivorship curve (Incorrect):
- Type II curves show constant mortality at all life stages, which does not match pioneer species.
Option (4) These species show Type I survivorship curve (Incorrect):
- Type I curves are typical of K-strategists (e.g., large mammals with high parental care), which do not match primary successional species.
