Browse By Unit
Jillian Holbrook
Karla Jauregui Sandoval
Jillian Holbrook
Karla Jauregui Sandoval
Population rates for species depend on the effectiveness of their reproductive strategies. Through comparing the reproductive strategies of species, we are prompted to ask:
In ecology, the terms "r-selected" and "K-selected" refer to the two ends of a spectrum of reproductive strategies that species can adopt.
R-selected species are those that have a high rate of reproduction and low investment in individual offspring. These species are adapted to environments where resources are scarce and unpredictable, and their strategy is to produce many offspring with the hope that a few will survive to reproduce. Examples of r-selected species include annual plants, insects, and some small mammals. 🐁
K-selected species, on the other hand, have a low rate of reproduction and a high investment in individual offspring. These species are adapted to environments where resources are more stable, and their strategy is to produce a smaller number of offspring but to use more resources in their survival. Examples of K-selected species include large mammals. 🐘
If a species has a high biotic potential and is able to reproduce and survive at high rates, it will have the potential to grow and expand its range quickly. On the other hand, if a species has a low biotic potential and is unable to reproduce and survive at high rates, it will have a slower rate of population growth and may be more vulnerable to extinction.
Because significant time, energy, and resources are invested into child rearing, K-selected species tend to have a Type I and Type II survivorship curve. Offspring live longer lives and grow slowly through an extended period of youth until their habitat hits the carrying capacity. K-selected species reproduce more than once in their lifetime, but competition for resources tends to be relatively high.
Because r-selected species must adapt quickly to their unpredictable habitats, these species experience lower competition for resources. However, r-selected species tend to only reproduce once in their lifetime.
| | K-selected | r-selected | | --- | --- | --- | | Size | Generally larger as species (terrestrial mammals) | Generally small | | Parenting | LOTS of parental care ➪time, energy, and resources in child rearing | Parents invest a little amount of time. energy and resources in children | | Family Size | Small ➪ few offspring per reproductive event ➪ long lifespans ➪ grow slowly until they hit carrying capacity | Large offspring per reproductive event ➪ short lifespan ➪ fast sexual maturity ➪ grow quickly but are followed by overshoots and die-offs - predator-prey relationships | | Competition | Highly competitive for resources (crowded niches) | Low competition for resources ➪ adapt quickly | | Eco. Succession | Late stage successors | Pioneer species | | Invasive species | Mostly affected by invasive species | Most invasive species are r selected because they reproduce quickly | | Examples | Humans, eagles, elephants, parrots, bison, and bears. | Insects, mice, bacteria, grasses, |
🎥 Watch this video here at 34 minutes to discuss this key topic more!
<< Hide Menu
Jillian Holbrook
Karla Jauregui Sandoval
Jillian Holbrook
Karla Jauregui Sandoval
Population rates for species depend on the effectiveness of their reproductive strategies. Through comparing the reproductive strategies of species, we are prompted to ask:
In ecology, the terms "r-selected" and "K-selected" refer to the two ends of a spectrum of reproductive strategies that species can adopt.
R-selected species are those that have a high rate of reproduction and low investment in individual offspring. These species are adapted to environments where resources are scarce and unpredictable, and their strategy is to produce many offspring with the hope that a few will survive to reproduce. Examples of r-selected species include annual plants, insects, and some small mammals. 🐁
K-selected species, on the other hand, have a low rate of reproduction and a high investment in individual offspring. These species are adapted to environments where resources are more stable, and their strategy is to produce a smaller number of offspring but to use more resources in their survival. Examples of K-selected species include large mammals. 🐘
If a species has a high biotic potential and is able to reproduce and survive at high rates, it will have the potential to grow and expand its range quickly. On the other hand, if a species has a low biotic potential and is unable to reproduce and survive at high rates, it will have a slower rate of population growth and may be more vulnerable to extinction.
Because significant time, energy, and resources are invested into child rearing, K-selected species tend to have a Type I and Type II survivorship curve. Offspring live longer lives and grow slowly through an extended period of youth until their habitat hits the carrying capacity. K-selected species reproduce more than once in their lifetime, but competition for resources tends to be relatively high.
Because r-selected species must adapt quickly to their unpredictable habitats, these species experience lower competition for resources. However, r-selected species tend to only reproduce once in their lifetime.
| | K-selected | r-selected | | --- | --- | --- | | Size | Generally larger as species (terrestrial mammals) | Generally small | | Parenting | LOTS of parental care ➪time, energy, and resources in child rearing | Parents invest a little amount of time. energy and resources in children | | Family Size | Small ➪ few offspring per reproductive event ➪ long lifespans ➪ grow slowly until they hit carrying capacity | Large offspring per reproductive event ➪ short lifespan ➪ fast sexual maturity ➪ grow quickly but are followed by overshoots and die-offs - predator-prey relationships | | Competition | Highly competitive for resources (crowded niches) | Low competition for resources ➪ adapt quickly | | Eco. Succession | Late stage successors | Pioneer species | | Invasive species | Mostly affected by invasive species | Most invasive species are r selected because they reproduce quickly | | Examples | Humans, eagles, elephants, parrots, bison, and bears. | Insects, mice, bacteria, grasses, |
🎥 Watch this video here at 34 minutes to discuss this key topic more!
© 2024 Fiveable Inc. All rights reserved.