Importance of Natural Resources

Video 5 Ecosystem Ecology


hi APESstudents welcome to video 5 it is on
ecosystem ecology so here are our objectives for video 5 I’ll let you
pause the video and kind of read through them but most of them are things that
you should probably remember from biology at least a little bit so levels
of organization you need to know and be able to put them in order and know what
they are organism is the same as an individual population is a group of
individuals or organisms community is multiple populations ecosystem now
includes abiotic factors of water air that sort of thing and then a biome we
know we’ve talked about already is a very very large area that includes lots
of different ecosystems so the factors that impact populations you have to
density dependent density independent basically density dependent depends on
the number of individuals that you have so things like food water disease those
all really depend on you know how how dense an area is so disease will flow
through a very dense population a lot differently than a very scattered
population additionally independent are things that
it doesn’t matter how many animals or plants there are one zebra or a hundred
zebras drought is going to impact those zebras in the same way and then carrying
capacity is limiting factors acting on a population so we know carrying capacity
is the number of individuals that our ecosystem can support and those limiting
factors like space and food are going to be impacting that carrying capacity so
we talked about abiotic and biotic factors be able to list out a few biotic
factors are basically all of your consumers and producers abiotic factors
are all of your nonliving things in the environment so things like the Sun
precipitation oxygen those sorts of things now down here when we have the
soil soil can be both a biotic and biotic because there’s bacteria in the
soil that are breaking down different organisms so again that one has living
and nonliving in it so some key words to know in terms of definitions are
keystone species and indicator species keystone species have an unusual large
impact on the ecosystem like the American alligator the L
and the wolf here is your keystone right here in the Ark and if you take that out
all of the other animals and organisms will basically collapse indicator
species have served as early warning signs for an environment most the time
they’re gonna be things like birds reptiles amphibians you may have heard
the canary in the coalmine which alerts the coal miners to low
oxygen levels if the bird dies so that’s an indicator species um so we’re gonna
talk about food chains and food webs now and producers are the base of all of our
food chains and food webs and they are producing all of our food they do this
by photosynthesis yes you need to know and memorize this formula if it helps
remember the numbers 666 okay not the greatest numbers in the
world but they will help you remember this formula so you have six carbon
dioxide’s you have six oxygens it’s producing glucose and six are sorry six
water’s in the beginning over here it’s producing six R its producing glucose
and six oxygens and then the opposite of aerobic respirate or opposite of
photosynthesis is respiration glucose and oxygen giving us carbon dioxide and
water so here’s our food chain we have our producers also known as an autotroph
if you don’t know that word we have our consumers also known as heterotrophs you
also need to be familiar with herbivore which is something that eats only plants
like our grasshopper you need to know carnivore eat only animals like the owl
and snake and omnivores eat both plants and animals like the bird so we look at
a more complex situation we have a food web which has multiple food chains in it
you’ll notice that the producers are at the bottom of the food web and the
consumers are at the top we also talked about a positive feedback loop in our
food webs and this is a trophic cascade so say for example I take out the
grasshopper remember a positive feedback loop is changing in the same direction
so if I take out the grasshopper the rat is also going to die off because it
doesn’t have a grasshopper to eat since the rat has died off the bird will have
shoes because the wolf is now only going to be feeding on that if the wolf is
only feeding on the birds then the dragonflies are going to have issues
because now the bird is not going to be around and now the dragonfly is going to
be feeding on these animals and then eventually the Frog will go extinct and
you see the idea here all of our organisms start to be impacted so again
this is a positive feedback loop multiple organisms are dying off because
even just a few are gone from our food web um so again the base is our
producers that gives us a hundred percent of energy in our food web and on
average about 10 percent is passed along into each next level so we lose a lot of
the energy as heat on the actual cost of doing business in your body digestion
all those sorts of things and then here’s actual numbers and I would draw
this pyramid or at least you know you don’t have to draw the animals or
anything but just label the pyramid and put some numbers in there so the
producers might give us 20,000 kilocalories meter squared per year then
I move up I only get about 10% so that’s 2,000 and then I have 220 and 2 so this
is pretty easy calculations here we’re just taking off a zero so what are some
of the things that our ecosystems do for us you should know these words
provisioning supporting cultural and regulating provisioning think like when
you get a food provision so how much food water you know wood things like
that we actually get supporting services or things that support the ecosystem so
nutrient cycling soil productivity that sort of thing regulating are things that
help regulate our ecosystem so climate water air regulation keeping the air and
the water clean then we have things that are more human and that’s a cultural
service so like spiritual aesthetic educational values for ecosystems so
we’re gonna talk about bioaccumulation and biomagnification now when you have
toxins in your food chain it can affect individuals they can also affect the
entire food chain so if it affects an individual and it accumulates inside the
tissues of one organism we call that
bioaccumulation okay if it then accumulates and goes up in the food
chain that is biomagnification okay so this is an individual over here by
accumulation by a magnification is increasing toxicity in each level of the
food chain okay and to give you an idea and kind of analogy for this I’m going
to play a quick game of pac-man you can play the idea that’s playing pacman
okay so I’m gonna go back over here so how does that relate to what we’re
talking about why in the world was Miss Jones playing pacman also imagine that
the pac-man is the consumer okay and the consumer is eating food these are the
little food pellets okay so a nomnomnom needs food okay
and some of that food had pollution in it so the blue dots are representing
pollution okay now you have the ghost which is gonna eat pac-man and that
ghost gets all of the pollution now the ghost is going to eat another pac-man
and it gets more pollution it’s going to eat another one it gets more pollution
you get the idea here so that’s biomagnification now you have a fish
it’s going to eat that ghost and it gets all of that pollution inside of it okay
getting another ghost and it gets even more pollution okay so that is what
biomagnification is and increase in pollutants with the trophic level so
what things bio magnify we’re gonna look at persistent organic pollutants and
mercury but these things are things that I am NOT excreting out so when I ingest
them they’re getting like absorbed into my tissues and they’re going to actually
be biologically active so they’re not just going to be urinated out so things
like persistent organic pollutants an example would be DDT so it’s present and
pesticides Plastics pretty much any industrial Kim
on the problem with DDT if you remember Rachel Carson is the one who told us
that DDT has some issues with our ecosystem and interfered with a bird’s
ability to produce calcium and calcium is really important to make the
eggshells very hard so the eggshells were really thin and then when the birds
set on the eggs to incubate them they would break and then of course the baby
birds cannot hatch another issue with pee Opie’s is the they are hormone
disruptors they mimic estrogen and so you end up having more females born than
males which is not good for the overall population mercury is also something
that bio magnifies so we burn coal and that releases mercury into the
atmosphere and then it can rain down and be deposited on land and water and once
it gets into bacteria it turns into this organic form methyl mercury and now
that’s what can get into our food chain and the streams that were tested in the
u.s. of the 300 every single one of them contained fish that had mercury
poisoning in it so this is one reason why you’re not supposed to eat a ton of
fish because it can accumulate in your body so what are the impacts of this
most of them are neurological blindness and deafness seizures muscle tone issues
delayed motor development and decreased brain size because they are neurological
and children are developing in uterus and uterus for pregnant women pregnant
women and children are the most at risk for these effects these are a fish that
you should eat versus one you shouldn’t North Carolina is a state that has a
fish advisory so if you catch anything from our waters you want to be careful
things that you should eat salmon is fine not so bad you know canned tuna is
starting to get up there shark and swordfish are things that you should not
eat a lot of because they’re gonna have a very high mercury content okay bring
your questions tomorrow thank you


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