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Ecological Succession

Added Nov 08, 2019 •

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Discussion of how an ecological system can go through changes, especially after disasters have occurred.

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so One More Concept that we have to cover an ecology is homeostasis in the changing ecosystem's homeostasis hopefully remember from earlier in the year it is a state of balance basically so there is a dynamic change that can occur dynamic equilibrium within a Neko we said the dynamic means that it can increase or decrease but it really comes back down to that same stable constant most of the time so conditions are going to be held more or less constant despite any changes in biotic living or abiotic non-living factors ecosystems tend to be dynamic nature they don't stay exactly the same overtime They do change slightly their characteristics will fluctuate just like population sizes will fluctuate and resource availability will fluctuate as well on this all depends on changes in the environment it was in the different populations that exist within an ecosystem but most ecosystems are capable of staying constant over long periods of time due to the complex ecosystem interactions that occur are there call biodiversity the diversity of living things if you are if you have an ecosystem with low biodiversity it's going to be very stable because if you remove even just one type of species you can set the entire ecosystem off so for example if you have any go system with low biodiversity and you remove one type of prey species that could be a problem for the the food chains in an ecosystem we're at as an ecosystem biodiversity changing environmental conditions declines in River City which will cause ecosystems resilience to decline we'll talk about that soon the end result is Hulu stability in the ecosystem and when you lose stability you run the threat of losing. Ecosystem entirely so ecosystems that are less stable than others might not be able to respond to the normal disturbances that occur within the environment whether it's weather or climate or a change in population numbers and that can damage the entire ecosystem as well as how well it functions of ecosystem resistance is when an ecosystem keeps its structure and and continues its normal functioning even if the environment changes so resistance means it's not going to give in to change very easily ecosystem resilience is after a disturbance your ecosystem returns back to normal so it was disturb for a while but is able to return to ecosystem resistance is more like it doesn't change because of a disturbance in the first place and ecosystem is yes it did change but it was able to come back to the way it was before and still be functional again changes in ecosystem conditions could be small biological or physical changes so you might have a forest canopy fall found or seasonal flood occur in some cases drastic changes within the ecosystem extreme changes like a volcanic eruption or a forest fire or change in the climate things like that could have more extreme changes ecosystems and it has a better chance of throwing it off balance entirely human class changes habitat instructions really big lawn pollution invasive species combustion and burning of fossil fuels those things can all disrupt an ecosystem and throw survival of specific species within that ecosystem so humans have a big influence over their environment and it is possible for us to see negative side effects from our activities within them ecological succession concept of how ecosystems change over time so succession is the sequence of changes in an ecosystem that regenerate a damaged Community or create community in a previously uninhabited area meaning maybe it's nearly existed there before and it destroyed by some kind of disturbance and succession shows how it comes back to be the way it was before succession can also show how an area that's never given or a sustained life before can now suddenly create an ecosystem living in living things together so the continuing process in all ecosystems succession is never really completely finished it's something that happens frequently in forests coral reefs are always building Marine pond in desert environments and it ends call the climax ecosystem which is like the most stable form of the ecosystem that's where it wants to be that's what it's fighting to get to and it's going to remain pretty unchanged from that climax ecosystem until some other disturbance comes into effect and push again so what does a general model of what succession looks like you start with small living things will he really start with non-living material and then you moved to smaller living organisms and they build up stage by stage by we're going to see some specific examples of succession as well primary succession is when you have the development of a community in an area that was previously uninhabited so this is the first time an ecosystem or a living thug life is going to be existing in that area so as an example if you have a volcanic eruption and now you have bear Rock because you have all this little side lava in an area or if you have a glacier scrape the face of a rock completely clean so there's not even any soil left this is one primary succession will occur so primary succession depends on the presence of unique organisms that can grow without soil and facilitate the process or help the process of soil formation so those are called pioneer species species are there Pioneers they're the first ones there are the first organisms in an ecosystem they help break down rock into smaller pieces to help create soil so you can't have plants even like grasses and certainly not larger plants like trees unless you have soil and environment so for primary succession to take place these pioneer species will go in and start breaking down that rock to create soil for those later species to plant themselves in the pioneer species. They also adding more organic matter to the habitat so that is a way that they help as well examples of pioneer species include lichens that's what you see in this picture over here a lichen is an example of mutualism between an algae and a fungus so they together we both benefit and the Lycan will come through and break rocks down into soil some mosses also act as pioneer species as well so this is what primary succession would look like you've got their rock over here seeing this picture but the Lycans would move into the Rock and start breaking that down into Terrier to get into soil and then when the like instead to add more organic matter to soil you get small annual plants you end up with grasses and perennials those are the ones that return each year winter grasses and shrubs and finally you have Oak and hickory trees in this case the city with all the climax community the most stable version of this ecosystem we also have a secondary succession that's when you reestablish in ecosystem used to exist that was damaged in some way so the plants and other organisms that are left behind by whatever this disturbance was are the ones they're going to start the process of regrowth so this occurs much more quickly than primary succession because at least you have soil some seeds and maybe some plants left behind your not starting completely from scratch so as an example if you have a fire that comes through this forest ecosystem you still have all of your soil present so I can just a couple of years you're going to start with those small plants add the perennials larger grasses and shrubs and once again you're going to get to your climax community or ecosystem which is the most stable form so the difference between the two types of succession or what they're starting with primary succession is the first equals intrigues us there when you start with bare rock and move your way up and with secondary succession you start with the soil and maybe even some roots and seeds from Plants left behind so this is a much quicker process some stages of succession last four just very short periods of time but others might take hundreds of years to occur so this really is a constant process disturbances to let you go system can affect how quickly or slowly succession occurs in a particular area, can usually secondary succession is more primary succession because you already have the soil present if it's just a moderate or small disturbance the air is going to be composed of habitats in different stages of succession so moderate disturbance might affect one part of the forest but not all of it so you're going to see different places stages of that change if you have frequent or intense to Services there is going to be characterized by the species present in the earliest stages of succession which makes sense because if you have like a Forest Community that's frequently hit with fire or some other statements like that that it can continuously has to go through that succession process over and over so the most common species of find are the earliest colonizers of the succession process so this last thing is just a table two processes again once more primary succession begins with no life in that area but secondary has a sort of present and potentially some plans Left Behind as well as follows the removal of existing buy Iota Iota means living things and there's no soil present but it's already here and secondary succession we create a new area for primary succession so it's brand new Leaf colonize an old area is used for secondary succession would primary succession you need those pioneer species lichen and Moss has with secondary succession the season Roots again they're already present in that soil and then in primary succession and all you have is there rock that make sense to you don't have much glue are there yet but with secondary succession you have a higher level of living materials so make sure you understand the difference between primary and secondary succession and that if you see one of those pictures we start with smaller plants that gradually grow taller over time recognize that a succession because that's a really important Concept in econ

Uploaded by Laura Lovelace.

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