Nov 04 2009
Niches Revisited
One of Mr. W’s favorite brain rules is #5, repeat to remember, so lets revisit what we learned yesterday about niches.
Every organism has a niche, but how are they determined?
- What you eat
- Where you work (habitat)
- Role in energy flow
- Role in matter cycling
- Interactions with others
When an organism’s environment changes, it has 3 choices. It can adapt, migrate, or die. Part of what we talked about today was organisms adapting to their environments to ensure survival.
The two types of niches we talked about today were fundamental and realized. A fundamental niche is very general; realized is specific within the fundamental niche. Think about it like report card comments. A teacher may say, “this student is doing well, but they have not reached their maximum potential.” The full potential of the student is similar to a fundamental niche, they have all this room to grow but have only realized a portion of it.
http://birdwatch.ph/images/gallery/lsplover1.jpg
This picture of the Sand-Plover shows both fundamental and realized niche. The fundamental niche extends past the boundaries of the picture, but the realized niche is that strip of land that the Sand-Plover is able to eat from. This bird has a long enough beak and legs to enter the water along the shore line and eat safely. This area is probably the farthest out it can reach for food. The flamingo, on the other hand, has much larger legs and can reach farther into the water; therefore, the flamingo travels into deeper water to catch its food. These different water levels are the realized niches of the different bird species. The fundamental niche is the whole area that is the coastline, where both birds can successfully eat from. Where the different birds eat is an example of resource partitioning. Species can occupy the same area (fundamental), but they become more specialized by adapting. If the birds didn’t adapt, they would be left with only 2 other options: migrate or die.
To review some niche descriptions:
- Keystone species
- Foundation species
- Indicator species
- Native species
- Nonnative species
Nice job, Julie! Not sure native and non-native really describe niches, rather they indicate whether or not a species evolved in a particular ecosystem/biome (or not). All are terms used to describe species.
So does this mean that the Sand Plover could adapt and, therefore, alter his realized niche over time? If natural selection was to occur over generations of a Sand Plover family, and a genetic mutation for the growth of longer legs was to spread throughout the whole Sand Plover population and prove to improve the bird’s strength, health, and ability to reproduce, would the Sand Plover then share a niche with the Flamingo? Then would competition ensue, leading to either coevolution or the exclusion of one species?
Sorry this question kind of rambled on, but all of the effects of natural selection and microevolution fit together and lead me to asking more questions.