Define succession, seral community (or sere), and climax community - ✔✔ succession- the process of change in the species structure and composition
... [Show More] of an ecological community over time.
It is more or less orderly and predictable changes following a disturbance or the initial colonization of a new habitat.
Usually discussed in terms of the plant species, but animal species present change with the changes in plant species
seral community (or sere)- an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained
climax community- the last stage of an ecosystem.
It is when the ecosystem has become balanced and there is little risk of an interfering event or change to mutate the environment.
Several rainforests and deserts qualify as being in the climax stage.
What is tricky about a climax stage is that given human development, any ecosystem that is in the climax stage now holds the risk of being destroyed and going backward in the stages.
What is primary succession? - ✔✔ This is when an ecological community first enters into a new form of habitat that it has not been present in before.
A good example of this would be the habitat created when granite is removed in a quarry. The rock face that is left behind is altered and becomes a new habitat.
Volcanic eruptions.
What grows within that habitat is considered to be in its primary stage.
Where (or under what conditions) would primary succession take place? See slide 5 for one example. - ✔✔ lifeless areas—regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier
volcanic eruptions
What are pioneer species? Intermediate species? Slide 7. Not the actual species, but where they fit in the succession pathway. - ✔✔ pioneer species- hardy species which are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by fire. Some lichens grow on rocks without soil, so may be among the first of life forms, and break down the rocks into soil for plants, first arrow
Intermediate species- specific species that create "connecting links" between the fossil record of life which help to demonstrate the gradual process of speciation and evolution, second arrow
first two arrows of primary secession
What is secondary succession? - ✔✔ The secondary succession stage occurs after a habitat has been established, but it is then disturbed or changed in some fashion and a new community moves in.
Changes can occur naturally (for example, lightening strike fire) or can be man made (for example, land cleared for farming and left fallow).
That ecological habitat has now entered its secondary stage.
Where (or under what conditions) would secondary succession take place? See slide 9 for examples. - ✔✔ Changes can occur naturally (for example, lightening strike fire) or can be man made (for example, land cleared for farming and left fallow).
a process started by an event (e.g. forest fire, harvesting, hurricane, etc.) that reduces an already established ecosystem (e.g. a forest or a wheat field) to a smaller population of species
What is a climax stage (or climax community or climax succession)? - ✔✔ the last stage of an ecosystem.
It is when the ecosystem has become balanced and there is little risk of an interfering event or change to mutate the environment.
Several rainforests and deserts qualify as being in the climax stage.
What is tricky about a climax stage is that given human development, any ecosystem that is in the climax stage now holds the risk of being destroyed and going backward in the stages.
Based on slide 12, does soil type impact succession? How (relative to the climax community)? - ✔✔ yes, depending on the soil, different things will grow
What are examples of how humans speed up or disrupt succession? - ✔✔ •Set-back succession or remove structure-terrestrial
•Allow/speed up succession or provide more structure-aquatic
•Provide artificial habitat "components"
4 stages of ecological succession - ✔✔ Pioneer - pioneer types are the new lifeforms that enter into a primary succession and begin to take hold. The pioneer has no connection to the environment, but it does find enough present in the new ecosystem to begin to establish its life.
Pioneer species are r-selected: fast growing, large number so young, easily disperse
Establishing - the establishing type can be hard to pinpoint because it crosses into the pioneer and sustaining. Establishing is the process in which lifeforms identify elements in an ecosystem that can sustain their basic needs - such as food, water and safe habitat.
Sustaining - Sustaining type means that life in the ecosystem has begun to enter into a pattern that allows for a cycle of life to continue. This means that birth and death are occurring, and there is little migration outside of the ecosystem - this is most common in the climax succession.
Sustaining species are K-selected: slow growing, few young, slower to disperse
Producing - the producing type occurs during the secondary succession. This is when lifeforms are breeding and growing, but there is migration because what is produced is also not capable of being supported within the ecosystem.
Slides 16 & 17. What is eutrophication and how do humans influence it? - ✔✔ eutrophication- the process by which a body of water becomes enriched in dissolved nutrients (such as phosphates) that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen. Dead organic matter builds up over time
Humans can influence rates of eutrophication; nutrients from fertilizers, organic waste speeds up the process
Eutrophic signifies a stage where the water body is rich in nutrients that are stimulating plant growth. The plants grow and die and the decaying plants release nutrients which further speed up the plant growth.
Eutrophication is natural, but people definitely have the ability to speed up the eutrophication process. The addition of nutrients to a system, like runoff from fertilizer, human sewage, pet waste, etc., can speed up the eutrophication process.
On slide 1, know the ages of the Universe, Earth and Homo sapiens. - ✔✔ Universe- about 14 billion years old
Earth- about 4.6 billion years old
Homo sapiens- have been around for about 250,000 years
What is the big bang theory? - ✔✔ the idea that all matter and energy in the universe began in an unimaginably dense state, and then space itself began expanding, started with a huge explosion [Show Less]