ENVS 200 CHAP 10 Flashcards
What is species richness?
It refers to the number of species in a given area, but the practice of counting species is difficult
What are diversity indices?
They are measures that combine both species richness and the evenness of the distribution of individuals among species.
ex. Shannon index
* DO PRACTICE QUESTIONS*
What is evenness?
It is how even or equitably distributed species are. Is the abundance of all species equal? The more equal, the more diverse it will be
What is niche breadth (n)?
niche breadth is a way of describing how flexible or specialized a species is in its ecological job or role..
Think of a “niche” as a job or role that an organism has in its environment. Now, “niche breadth” (often represented by the symbol ‘n’) refers to how versatile or flexible a species is in terms of the different tasks or roles it can handle within its environment.
In simpler terms, if a species has a broad niche breadth (higher ‘n’), it means that it can do a variety of things well and adapt to different conditions. It’s like having a wide skill set that allows the species to thrive in various situations. On the other hand, a species with a narrow niche breadth (lower ‘n’) might be more specialized, excelling in a specific role but not as adaptable to different environmental conditions.
What is niche overlap (o)?
It is when the niches of adjacent species overlap. The average is described by o-bar.
ex. the greater o-bar is, the more species there are that coexist on the resource continuum
What is the productivity hypothesis?
in simple terms, suggests that the amount of life (biomass) an ecosystem can support is directly related to the amount of energy it receives and uses for plant growth.
Imagine an ecosystem as a garden. The productivity hypothesis argues that the more sunlight, nutrients, and water that the garden receives, the more plants it can grow. These plants, in turn, provide food and energy for other organisms, such as herbivores (plant-eaters) and carnivores (meat-eaters). So, the overall productivity, or the ability to support life, is linked to the energy available for plant growth.
In ecosystems, this concept is often applied to the idea that areas with higher sunlight, more nutrients, and better conditions for plant growth will generally support a larger and more diverse community of living organisms. In contrast, areas with limited resources may support fewer and less diverse species. The productivity hypothesis helps scientists understand how energy flows through ecosystems and influences the abundance and diversity of life within them.
What is the energy hypothesis?
In simple terms, it suggests that the amount of energy available in an ecosystem determines the number and variety of species it can support.
Think of an ecosystem as a kind of “energy budget.” If there’s a lot of sunlight, which plants use to make food through photosynthesis, and this energy is efficiently transferred to various organisms through the food chain, then the ecosystem can support a greater number and diversity of species. More energy means more life.
On the other hand, if there’s less energy available, perhaps due to factors like limited sunlight or inefficient energy transfer between different organisms, the ecosystem might support fewer species, and they may struggle to thrive.
In essence, the energy hypothesis helps scientists understand how the flow of energy through an ecosystem influences the overall health, diversity, and abundance of life within that ecosystem. It emphasizes the role of energy as a key factor in shaping the structure and dynamics of ecological communities.
What is eutrophication?
It occurs when human activities lead to an increased input of nutrients (nitrates, phosphates, etc.) into waterways, like lakes, rivers, estuaries, etc.
What is the paradox of enrichment?
It is when there is increased food available to the prey, which causes the predators population to destabilize.
ex. lots of food for rabbits makes them overabundant, so the pop grows unbounded, so then the lynx pop will grow unsustainably larger that will eventually result in a crash that could lead to extinction
What is particulate organic carbon (POC)?
Particulate Organic Carbon (POC) is basically small, solid pieces of material that come from living or once-living things, and these pieces contain carbon.
In the context of the environment, POC often refers to small particles of plant or animal matter in water or air. It’s an important aspect of ecosystems because it represents a form of carbon that’s part of the natural cycle of life and plays a role in various biological processes. Scientists study POC to understand more about how carbon moves through ecosystems and influences the health of our planet.
What is alpha-diversity?
It refers to diversity at the local scale (within a community), so it is high when there are many species
What is beta-diversity?
It refers to the differences among communities within a region, so it is high when different communities in a region differ in the species they contain (found by dividing gamma by the average of alpha)
What is gamma-diversity?
It refers to diversity at a whole, regional scale (collection of communities), so it combines alpha and beta diversity and is highest when both individual communities are diverse/communities in the region differ. (found by adding the alpha diversity of all communities together)
What is potential evapotranspiration (PET)?
It is the amount of water that would evaporate or be transpired from a saturated surface and therefore measures atmospheric energy
What is net primary productivity (NPP)?
It is GPP-R auto and represents the actual rate of new biomass production available for consumption by heterotrophs
