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Ecological Succession

Added Oct 07, 2015 •

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Great overview for Chap. 4 Section 1

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hides mr. Anderson and in this podcast I'm going to talk about ecological succession Russian is simply a series of events by which life comes back into what am I talking about well look here we've got a picture of a forest but this is a year after there forest fire in so you can see a lot of the charred burnt trunks it's a basically a photographer came here and he came here once a year to the same place and took fish inside this to be your one the sippy year to the city year 3  year for  in year five and so basically what you see is Life coming back and changes taking place and that is called succession and it tends to occur at a connectable rate and using them number of predictable species it's a basically succession we could break into two different parts the first one is called primary succession primary succession occurs when you have bare rock in other ones when there's no soil left and so if you look at this a lava flow basically the lava flow down here you can see the I cut a footpath year but basically Life is starting to come back life can't grow out here for the most part because there's no soil there we can't have plants that start to grow their what's so we have to have a rosion we have to have wind and rain and eventually we have soil and then we can start have plans come back another example of primary succession is right here this is for Mount Saint Helens the day before it exploded after it exploded it look just like this and so here in Montana we had about that much Ash everywhere just came from the top of this mountain as it exploded well this should be primary succession cuz there's no soil left it's all gone it's in Montana not in Washington and so basically like to reestablish itself and said this is a picture of Mount Saint Helens now the few years ago and so this is on this kind of noun this Rim up here I'm so what's had to happen a series of events by which life is come back now if you compare this to that Estonian Forest you can see that it's coming slower and that's because we had to go all the way down to the Rock great example of this is the island of surtsey and so I think this is a 1962 all the sudden off the coast of Iceland there's huge volcano in a brand new island shows up in Emmett surtsey which is some Norse god and so basically what scientist decided to do is to not go there a few scientists will go there every year it's basically to study how life comes back and so you can see all this vegetation on this island and there's been weathering going on just think this isn't just a regular Island in this really not that old answer the cool thing is they can see what species are showing up first it didn't take long for vascular to show up and you might think how did they get there well lot of them are blown by the wind or carried by birds or float there and so it's pretty cool but all of that again is prime succession secondary succession in this is a gorgeous picture that was taken here in Montana during a forest fire secondary succession occurs when you have some kind of a disturbance but the Still Remains and actually the burning of fires is something that's really common in the mountains and so you can see the selkie or after the fires in Yellowstone Park and there's no vegetation but what you should know is it the soil is sitting there and life is ready to come back and so basically this is what Yellowstone Park look like a few years later and then looks like napped and so what were some of the first organisms to come in what we tend to call these things Pioneer organisms and Pioneer organisms are going to be organisms that tend to make their Rain by coming into an area after there's a disturbance in the two examples in Montana when would be Lupin Lupin is going to be a flower it's actually a legume so related to a p what's a nice about Lupin is that it can fix nitrogen has bacteria that live on its roots and they can actually take nitrogen in the air and return it to the soil then another example to be Lodgepole Pines Lodgepole Pines are really skinny and long Conifer trees that we have here in Montana and basically what they do is they have two different cones they have certain cones that they use your 2-year to reproduce but they also have these really waxy what are called Sir rottenness cones and they're just filled with wax and they never open unless there's a fire and if there's a fire then they'll open up and then their seeds will come back it's a basically Lodgepole Pine have evolved this new is there way to be a pioneer species to come in now eventually as that for starts to develop it's going to be replaced by more climax species and so that's another term that I just that's called the climax climax is basically what's going to happen after succession so on this side will have a disturbance organ of a disturbance on so what are some disturbances we could have fire or human disturbances or like a tsunami on a really cool disturbances after Chernobyl all down there all humans had to leave and so it's a wild kind of a land but basically life can come back and how does it come back will let's look at this chart which is great so we look at bear bear rocks going to be the first thing that you have and you matter bear rock is going to drop off as vegetation of course starts to come in what's next will then we're going to mosses and grasses come why don't they come right away well lots of times there's no soil there and so we have to have weathering rain wind and then we start to get soil and then they can come back now you might think well why don't they just stay forever I just have a huge amount of these grasses well if you think about it as the other species are to take off their going to be taller than those grasses they're going to start to take the sunlight and said there play replaced by other species which is eventually we're going to have some small wooden plants and they're going to have some trees this would be like the Lodgepole Pine and eventually we have some is it come back like that and so what happens eventually everything kind of levels off and then we have these climax species at the end does it stay like that forever well it depends so if you're like a redwood tree you're big enough that fire sweeping through an area is not going to affect you but most PCS are going to be killed by a disturbance and then that whole process over again it's a what is succession is the series of steps by which life comes back remember there's primary secondary primary no soil secondary soil and I hope

Uploaded by Greg Grammer.

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