Glossary
K-selected species
Species that produce few offspring but invest heavily in their survival, typically having long lifespans and stable populations.
Example:
Grizzly bears are K-selected species; they have a long gestation period, raise only a few cubs, and provide extensive maternal care.
Mortality Patterns
The characteristic ways in which individuals within a population die over their lifespan, often depicted by survivorship curves.
Example:
A high infant Mortality Pattern in a species suggests that many offspring die very young, which is common for species that produce many offspring.
Parental Care
The investment of time and energy by parents to ensure the survival and development of their offspring.
Example:
Species with extensive Parental Care, like wolves raising their pups, typically have higher offspring survival rates.
Population Dynamics
The study of how populations change in size, density, dispersion, and age structure over time, influenced by factors like birth rates, death rates, immigration, and emigration.
Example:
Understanding the Population Dynamics of deer helps wildlife managers set appropriate hunting quotas to maintain healthy herd sizes.
Reproductive Strategies
The set of adaptations in an organism that influence its reproductive success, including the number of offspring, parental care, and lifespan.
Example:
A species' Reproductive Strategies determine whether it invests in many small offspring or a few large, well-cared-for offspring.
Survivorship Curves
Graphs that illustrate the proportion of individuals in a population likely to survive to different ages, providing insight into mortality patterns across species.
Example:
Ecologists use Survivorship Curves to compare the life histories of species, like seeing how many sea turtles survive past their hatchling stage versus how many humans live to old age.
Type I Survivorship Curve
A curve characterized by high survival rates throughout most of the lifespan, with a sharp increase in mortality only in old age.
Example:
Elephants, which invest heavily in a few offspring and protect them for many years, exhibit a Type I Survivorship Curve.
Type II Survivorship Curve
A curve showing a relatively constant death rate throughout the lifespan, meaning an individual's age does not significantly affect their probability of survival.
Example:
Many bird species, like robins, face a consistent risk of predation or disease throughout their lives, illustrating a Type II Survivorship Curve.
Type III Survivorship Curve
A curve marked by very high mortality rates early in life, with only a small fraction of individuals surviving to old age.
Example:
A single oyster can release millions of eggs, but very few survive to adulthood, demonstrating a classic Type III Survivorship Curve.
r-selected species
Species that produce many offspring with little to no parental care, often having short lifespans and fluctuating populations.
Example:
Dandelions are r-selected species, producing thousands of seeds that disperse widely with no parental investment beyond seed production.