[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.98,0:00:01.74,Default,,0000,0000,0000,,So...
Dialogue: 0,0:00:01.97,0:00:04.82,Default,,0000,0000,0000,,in your book in Chapter 17
Dialogue: 0,0:00:05.92,0:00:08.77,Default,,0000,0000,0000,,the importance of wolves to the \NYellowstone ecosystem
Dialogue: 0,0:00:09.58,0:00:11.24,Default,,0000,0000,0000,,is the main topic.
Dialogue: 0,0:00:12.53,0:00:16.34,Default,,0000,0000,0000,,And we have talked already about \Nthe connections between living things
Dialogue: 0,0:00:16.63,0:00:17.95,Default,,0000,0000,0000,,and their environment;
Dialogue: 0,0:00:18.12,0:00:19.95,Default,,0000,0000,0000,,and how there are different
Dialogue: 0,0:00:20.38,0:00:21.90,Default,,0000,0000,0000,,types of interactions.
Dialogue: 0,0:00:22.40,0:00:24.44,Default,,0000,0000,0000,,We also found out that wolves fulfill
Dialogue: 0,0:00:25.04,0:00:26.92,Default,,0000,0000,0000,,a very important role in the community:
Dialogue: 0,0:00:26.92,0:00:28.55,Default,,0000,0000,0000,,they're a keystone species.
Dialogue: 0,0:00:28.87,0:00:30.86,Default,,0000,0000,0000,,Which means that they have a really
Dialogue: 0,0:00:31.25,0:00:34.56,Default,,0000,0000,0000,,big influence for their population size \Non the community structure;
Dialogue: 0,0:00:35.21,0:00:38.77,Default,,0000,0000,0000,,and their presence or absence can really \Nchange that community structure.
Dialogue: 0,0:00:39.62,0:00:41.36,Default,,0000,0000,0000,,Wolves occupy
Dialogue: 0,0:00:41.90,0:00:45.36,Default,,0000,0000,0000,,a very important niche in the \NYellowstone ecosystem.
Dialogue: 0,0:00:45.90,0:00:48.41,Default,,0000,0000,0000,,And a niche simply refers to,
Dialogue: 0,0:00:48.77,0:00:51.21,Default,,0000,0000,0000,,what is an organisms role in \Nits environment?
Dialogue: 0,0:00:51.50,0:00:52.66,Default,,0000,0000,0000,,What does it do?
Dialogue: 0,0:00:52.90,0:00:55.10,Default,,0000,0000,0000,,Who does it interact with, and how?
Dialogue: 0,0:00:55.10,0:00:56.61,Default,,0000,0000,0000,,What are its needs?
Dialogue: 0,0:00:56.82,0:00:59.64,Default,,0000,0000,0000,,So, really, the needs and the...
Dialogue: 0,0:01:00.06,0:01:01.75,Default,,0000,0000,0000,,interactions of an organism
Dialogue: 0,0:01:01.75,0:01:02.87,Default,,0000,0000,0000,,in an ecosystem
Dialogue: 0,0:01:03.19,0:01:05.06,Default,,0000,0000,0000,,describe this concept of a niche.
Dialogue: 0,0:01:05.41,0:01:07.06,Default,,0000,0000,0000,,Basically, everything about how
Dialogue: 0,0:01:08.03,0:01:09.87,Default,,0000,0000,0000,,it acts in that ecosystem.
Dialogue: 0,0:01:10.44,0:01:12.68,Default,,0000,0000,0000,,If there is overlap of a niche,
Dialogue: 0,0:01:13.10,0:01:15.40,Default,,0000,0000,0000,,a place where needs and roles overlap,
Dialogue: 0,0:01:15.74,0:01:20.01,Default,,0000,0000,0000,,then we get our last type of biological \Ninteraction: competition.
Dialogue: 0,0:01:20.84,0:01:22.60,Default,,0000,0000,0000,,Competition is going to take place
Dialogue: 0,0:01:22.80,0:01:24.34,Default,,0000,0000,0000,,when two organisms,
Dialogue: 0,0:01:24.96,0:01:26.15,Default,,0000,0000,0000,,two species,
Dialogue: 0,0:01:26.59,0:01:29.02,Default,,0000,0000,0000,,or two members of the same species
Dialogue: 0,0:01:29.60,0:01:34.98,Default,,0000,0000,0000,,are interacting in a way that indicates \Nthat they are competing for a resource.
Dialogue: 0,0:01:35.49,0:01:38.42,Default,,0000,0000,0000,,So, for example, here we have a \Nlittle parakeet
Dialogue: 0,0:01:38.94,0:01:42.05,Default,,0000,0000,0000,,and a starling that are fighting \Nover a french fry.
Dialogue: 0,0:01:43.38,0:01:45.24,Default,,0000,0000,0000,,Now, hypothetically...
Dialogue: 0,0:01:46.34,0:01:47.97,Default,,0000,0000,0000,,in the case of competition,
Dialogue: 0,0:01:48.18,0:01:52.64,Default,,0000,0000,0000,,one competitor will usually manage to \Nexclude the other competitor for that
Dialogue: 0,0:01:52.64,0:01:53.96,Default,,0000,0000,0000,,--from that resource--
Dialogue: 0,0:01:53.96,0:01:56.27,Default,,0000,0000,0000,,and we refer to this as \Ncompetitive exclusion.
Dialogue: 0,0:01:56.98,0:01:58.100,Default,,0000,0000,0000,,Organisms can compete for lots of things.
Dialogue: 0,0:01:59.70,0:02:01.38,Default,,0000,0000,0000,,They can compete for space,
Dialogue: 0,0:02:01.60,0:02:03.08,Default,,0000,0000,0000,,like these corals.
Dialogue: 0,0:02:03.31,0:02:04.22,Default,,0000,0000,0000,,Um...
Dialogue: 0,0:02:04.58,0:02:06.83,Default,,0000,0000,0000,,the corals are also competing \Nfor sunlight.
Dialogue: 0,0:02:07.05,0:02:10.42,Default,,0000,0000,0000,,There is some algae sort of growing\Nhere in the corner of the picture;
Dialogue: 0,0:02:10.42,0:02:14.20,Default,,0000,0000,0000,,and as that algae grows over the coral \Nit takes up the sunlight and the coral
Dialogue: 0,0:02:14.20,0:02:15.21,Default,,0000,0000,0000,,can't get it.
Dialogue: 0,0:02:15.44,0:02:18.04,Default,,0000,0000,0000,,So organisms can compete for physical \Nresources like:
Dialogue: 0,0:02:18.04,0:02:20.79,Default,,0000,0000,0000,,space, sunlight, nutrients,\Nwater, things like that.
Dialogue: 0,0:02:22.15,0:02:24.15,Default,,0000,0000,0000,,Organisms can compete for food.
Dialogue: 0,0:02:24.70,0:02:27.32,Default,,0000,0000,0000,,The lions and hyenas are competing \Nfor food here.
Dialogue: 0,0:02:27.88,0:02:30.72,Default,,0000,0000,0000,,You saw some competition in the \N"Battle At Krueger" video.
Dialogue: 0,0:02:31.04,0:02:34.54,Default,,0000,0000,0000,,There was some very interesting\Ncompetitive interactions taking place.
Dialogue: 0,0:02:35.80,0:02:37.61,Default,,0000,0000,0000,,Organisms can compete for mates.
Dialogue: 0,0:02:37.79,0:02:39.86,Default,,0000,0000,0000,,These are two male elephant seals,
Dialogue: 0,0:02:40.00,0:02:42.61,Default,,0000,0000,0000,,uh, who are competing to become \Nthe "beach master."
Dialogue: 0,0:02:42.93,0:02:47.85,Default,,0000,0000,0000,,And that is a real term that describes the\Nmale elephant seal that has control of
Dialogue: 0,0:02:47.85,0:02:49.56,Default,,0000,0000,0000,,all the females on the beach.
Dialogue: 0,0:02:49.82,0:02:52.28,Default,,0000,0000,0000,,Elephant seals have a harem mating system
Dialogue: 0,0:02:52.69,0:02:55.39,Default,,0000,0000,0000,,where one male mates with the females,\Nand, of course,
Dialogue: 0,0:02:55.70,0:02:59.76,Default,,0000,0000,0000,,for that evolutionary fitness, for that\Nreproductive success,
Dialogue: 0,0:03:00.26,0:03:04.15,Default,,0000,0000,0000,,that is a very hotly contested position.
Dialogue: 0,0:03:04.62,0:03:08.48,Default,,0000,0000,0000,,You can see they are battling pretty hard.\NThey are bloody and fighting, uhm...
Dialogue: 0,0:03:08.48,0:03:11.100,Default,,0000,0000,0000,,What's really interesting about the \Nelephant seal situation is that you do
Dialogue: 0,0:03:11.100,0:03:14.05,Default,,0000,0000,0000,,have a little bit of disruptive selection.
Dialogue: 0,0:03:14.05,0:03:16.76,Default,,0000,0000,0000,,There are "sneaker males," as well,\Nin that system.
Dialogue: 0,0:03:17.58,0:03:20.40,Default,,0000,0000,0000,,But, there is very intense competition \Nfor mates.
Dialogue: 0,0:03:23.40,0:03:25.06,Default,,0000,0000,0000,,When organisms compete
Dialogue: 0,0:03:25.06,0:03:27.25,Default,,0000,0000,0000,,they can compete in different ways.
Dialogue: 0,0:03:27.73,0:03:32.36,Default,,0000,0000,0000,,Some organisms compete by taking up, \Nusing up a resource.
Dialogue: 0,0:03:32.90,0:03:35.90,Default,,0000,0000,0000,,And we refer to this as exploitation \Ncompetition.
Dialogue: 0,0:03:35.90,0:03:39.40,Default,,0000,0000,0000,,Now, this is different from the \Nexploitation that we talked about earlier
Dialogue: 0,0:03:39.40,0:03:42.96,Default,,0000,0000,0000,,when we talked about how parasites \Nand predators exploit other organisms.
Dialogue: 0,0:03:43.57,0:03:47.55,Default,,0000,0000,0000,,In the case of exploitation competition, \Nyou can also think of it as "scramble."
Dialogue: 0,0:03:48.14,0:03:49.84,Default,,0000,0000,0000,,This squirrel is hoarding nuts.
Dialogue: 0,0:03:50.42,0:03:54.30,Default,,0000,0000,0000,,He's gathered up nuts and he is sitting\Non them and he's com--com--com...
Dialogue: 0,0:03:54.98,0:03:58.84,Default,,0000,0000,0000,,um, taking up that resource and \Nkeeping other organisms from getting it.
Dialogue: 0,0:03:59.82,0:04:03.62,Default,,0000,0000,0000,,So exploitation competition can happen\Nwhen an organism uses up a resource
Dialogue: 0,0:04:04.16,0:04:06.66,Default,,0000,0000,0000,,and doesn't allow other organisms to \Naccess it.
Dialogue: 0,0:04:07.65,0:04:09.94,Default,,0000,0000,0000,,Interference competition, \Non the other hand,
Dialogue: 0,0:04:10.38,0:04:14.71,Default,,0000,0000,0000,,is when you have organisms that are \Nphysically competing, or interfering,
Dialogue: 0,0:04:14.71,0:04:16.52,Default,,0000,0000,0000,,with one another for a resource.
Dialogue: 0,0:04:16.77,0:04:19.44,Default,,0000,0000,0000,,This is sometimes referred to as \N"contest competition."
Dialogue: 0,0:04:19.69,0:04:21.60,Default,,0000,0000,0000,,So, in this case you have a, uh...
Dialogue: 0,0:04:22.23,0:04:26.16,Default,,0000,0000,0000,,a little ground squirrel and some \Nstarlings that are competing for nuts.
Dialogue: 0,0:04:26.68,0:04:30.07,Default,,0000,0000,0000,,And, instead of--instead of the ground \Nsquirrel hogging all the nuts
Dialogue: 0,0:04:30.07,0:04:31.74,Default,,0000,0000,0000,,and just setting them aside,
Dialogue: 0,0:04:32.08,0:04:35.21,Default,,0000,0000,0000,,instead what we have is an actual, \Nphysical altercation,
Dialogue: 0,0:04:35.63,0:04:37.69,Default,,0000,0000,0000,,a fight if you will, for that resource.
Dialogue: 0,0:04:38.44,0:04:41.57,Default,,0000,0000,0000,,So, exploitation competition: \Nusing up the resources.
Dialogue: 0,0:04:42.10,0:04:45.82,Default,,0000,0000,0000,,Interference competition: physically \Ncompeting over them and--and
Dialogue: 0,0:04:46.34,0:04:48.87,Default,,0000,0000,0000,,physically keeping other organisms from\Nhaving them.
Dialogue: 0,0:04:49.94,0:04:52.63,Default,,0000,0000,0000,,So those are two different strategies \Nfor competition.
Dialogue: 0,0:04:52.63,0:04:55.88,Default,,0000,0000,0000,,And depending on the organism and \Nthe resource, you might see either
Dialogue: 0,0:04:55.88,0:04:56.99,Default,,0000,0000,0000,,of those take place.
Dialogue: 0,0:04:58.61,0:05:02.40,Default,,0000,0000,0000,,The coral example here, we have the \Nalgae is engaging
Dialogue: 0,0:05:02.40,0:05:04.84,Default,,0000,0000,0000,,in exploitation competition by
Dialogue: 0,0:05:04.84,0:05:07.63,Default,,0000,0000,0000,,covering up the coral and keeping it \Nfrom getting light.
Dialogue: 0,0:05:08.22,0:05:11.98,Default,,0000,0000,0000,,The elephant seals are engaging in \Ninterference competition
Dialogue: 0,0:05:12.40,0:05:14.25,Default,,0000,0000,0000,,by physically battling one another
Dialogue: 0,0:05:14.44,0:05:15.57,Default,,0000,0000,0000,,for the mates.
Dialogue: 0,0:05:17.07,0:05:17.86,Default,,0000,0000,0000,,Okay...
Dialogue: 0,0:05:18.59,0:05:20.15,Default,,0000,0000,0000,,When competition occurs
Dialogue: 0,0:05:20.91,0:05:22.36,Default,,0000,0000,0000,,one of the things that we see
Dialogue: 0,0:05:22.84,0:05:25.12,Default,,0000,0000,0000,,is that one competitor,
Dialogue: 0,0:05:27.49,0:05:29.79,Default,,0000,0000,0000,,if they have the same exact needs,
Dialogue: 0,0:05:30.27,0:05:32.40,Default,,0000,0000,0000,,will often out compete the other \Npredator.
Dialogue: 0,0:05:32.89,0:05:34.33,Default,,0000,0000,0000,,So here are two protists.
Dialogue: 0,0:05:34.88,0:05:37.61,Default,,0000,0000,0000,,Um , Paramecium aurelia and\NParamecium caudatum.
Dialogue: 0,0:05:38.10,0:05:40.03,Default,,0000,0000,0000,,That, if grown in separate flasks,
Dialogue: 0,0:05:40.38,0:05:41.60,Default,,0000,0000,0000,,in separate conditions,
Dialogue: 0,0:05:41.60,0:05:44.78,Default,,0000,0000,0000,,we see almost the exact same \Npopulation growth curves.
Dialogue: 0,0:05:44.78,0:05:46.35,Default,,0000,0000,0000,,They grow in the same way.
Dialogue: 0,0:05:47.65,0:05:50.45,Default,,0000,0000,0000,,If, however, we put them in the same flask
Dialogue: 0,0:05:51.03,0:05:56.00,Default,,0000,0000,0000,,Paramecium aurelia ultimately out competes\NParamecium caudatum
Dialogue: 0,0:05:57.46,0:06:02.15,Default,,0000,0000,0000,,because two organisms cannot occupy\Nthe same niche simultaneously
Dialogue: 0,0:06:02.15,0:06:03.66,Default,,0000,0000,0000,,and continuously.
Dialogue: 0,0:06:04.42,0:06:06.90,Default,,0000,0000,0000,,This is known as competitive exclusion.
Dialogue: 0,0:06:07.25,0:06:10.13,Default,,0000,0000,0000,,So, the parrot and the starling competing \Nfor a french fry,
Dialogue: 0,0:06:10.13,0:06:13.31,Default,,0000,0000,0000,,if they lived in the exact same \Nenvironment and only ate the same
Dialogue: 0,0:06:13.31,0:06:17.72,Default,,0000,0000,0000,,food, over time what we would see \Nis one competitor would be a superior
Dialogue: 0,0:06:17.72,0:06:21.42,Default,,0000,0000,0000,,competitor; out compete the other one.\Nand we would get competitive exclusion.
Dialogue: 0,0:06:23.25,0:06:26.60,Default,,0000,0000,0000,,How organisms get around this is through \Nresource partitioning.
Dialogue: 0,0:06:27.57,0:06:28.38,Default,,0000,0000,0000,,For example:
Dialogue: 0,0:06:28.78,0:06:30.88,Default,,0000,0000,0000,,this is a group of birds, warblers, \N
Dialogue: 0,0:06:30.88,0:06:32.33,Default,,0000,0000,0000,,a closely related species,
Dialogue: 0,0:06:32.80,0:06:34.94,Default,,0000,0000,0000,,that are engaging in \Nresource partitioning.
Dialogue: 0,0:06:34.94,0:06:36.54,Default,,0000,0000,0000,,They use different resources
Dialogue: 0,0:06:37.51,0:06:38.98,Default,,0000,0000,0000,,to allow them
Dialogue: 0,0:06:38.98,0:06:40.65,Default,,0000,0000,0000,,to effectively coexist.
Dialogue: 0,0:06:42.19,0:06:45.26,Default,,0000,0000,0000,,So, some of the warblers use \Ndifferent parts of the tree.
Dialogue: 0,0:06:45.66,0:06:49.61,Default,,0000,0000,0000,,The myrtle warbler, for example, is found\Nin the mid-section, the lower mid-section
Dialogue: 0,0:06:49.61,0:06:50.43,Default,,0000,0000,0000,,of the tree.
Dialogue: 0,0:06:50.43,0:06:53.52,Default,,0000,0000,0000,,While the cape may warbler is found\Nat the tops of the trees.
Dialogue: 0,0:06:54.16,0:06:55.48,Default,,0000,0000,0000,,They eat different things.
Dialogue: 0,0:06:55.48,0:06:58.77,Default,,0000,0000,0000,,Black throated warblers that live sort of \Nnear the tops are eating
Dialogue: 0,0:06:58.77,0:07:00.70,Default,,0000,0000,0000,,small worms and grubs.
Dialogue: 0,0:07:00.70,0:07:04.51,Default,,0000,0000,0000,,Where cape may warblers are actually\Nuh, eating flying insects.
Dialogue: 0,0:07:05.51,0:07:09.77,Default,,0000,0000,0000,,So we have different forms of competition
Dialogue: 0,0:07:10.07,0:07:12.100,Default,,0000,0000,0000,,different types of resources being\Nused here.
Dialogue: 0,0:07:13.44,0:07:15.56,Default,,0000,0000,0000,,Different spaces, different food items...
Dialogue: 0,0:07:16.29,0:07:19.74,Default,,0000,0000,0000,,And so these birds have engaged\Nin resource partitioning
Dialogue: 0,0:07:20.18,0:07:23.51,Default,,0000,0000,0000,,where they take advantage of \Ndifferent resources
Dialogue: 0,0:07:24.04,0:07:27.07,Default,,0000,0000,0000,,so that they can still gain a foothold \Nin the ecosystem.
Dialogue: 0,0:07:27.80,0:07:30.42,Default,,0000,0000,0000,,One of the things we might see \Nhere though is that
Dialogue: 0,0:07:30.42,0:07:35.04,Default,,0000,0000,0000,,some areas of this tree, or some types of \Ninsect prey may not be as desire--
Dialogue: 0,0:07:35.04,0:07:36.39,Default,,0000,0000,0000,,as desirable as others.
Dialogue: 0,0:07:37.14,0:07:41.72,Default,,0000,0000,0000,,So that when one resource is \Nremoved, or one competitor is removed
Dialogue: 0,0:07:42.01,0:07:43.48,Default,,0000,0000,0000,,we might see changes.
Dialogue: 0,0:07:43.70,0:07:47.31,Default,,0000,0000,0000,,And so competition really can \Ninfluence distributions in time and space.
Dialogue: 0,0:07:47.71,0:07:49.78,Default,,0000,0000,0000,,Here is an example from the \NOregon Coast.
Dialogue: 0,0:07:51.17,0:07:54.76,Default,,0000,0000,0000,,We have two different species that are \Nliving on the coastline here,
Dialogue: 0,0:07:55.00,0:07:56.22,Default,,0000,0000,0000,,we have barnacles
Dialogue: 0,0:07:56.61,0:07:57.89,Default,,0000,0000,0000,,and we have mussels.
Dialogue: 0,0:07:58.22,0:08:01.36,Default,,0000,0000,0000,,And these two organisms both like to \Nlive in the inner tidal zone.
Dialogue: 0,0:08:01.36,0:08:05.37,Default,,0000,0000,0000,,This is an area between the high and low \Ntides that is partially covered by water
Dialogue: 0,0:08:05.37,0:08:07.33,Default,,0000,0000,0000,,during a portion of the day .
Dialogue: 0,0:08:08.18,0:08:11.13,Default,,0000,0000,0000,,And mussels tend to be very quickly \Ngrowing.
Dialogue: 0,0:08:11.37,0:08:14.61,Default,,0000,0000,0000,,They grow fast, they are a little \Nbit bigger, and they can actually
Dialogue: 0,0:08:14.61,0:08:16.28,Default,,0000,0000,0000,,-and you see this happening here-
Dialogue: 0,0:08:16.28,0:08:18.46,Default,,0000,0000,0000,,they can crush and squeeze out barnacles.
Dialogue: 0,0:08:19.04,0:08:23.15,Default,,0000,0000,0000,,They are engaging in some exploitation \Ncompetition where they are physically
Dialogue: 0,0:08:23.15,0:08:26.34,Default,,0000,0000,0000,,taking up a resource and keeping other \Norganisms from getting it.
Dialogue: 0,0:08:27.44,0:08:29.02,Default,,0000,0000,0000,,The problem that mussels have
Dialogue: 0,0:08:30.86,0:08:31.86,Default,,0000,0000,0000,,is that...
Dialogue: 0,0:08:33.81,0:08:37.19,Default,,0000,0000,0000,,while they are competitively excluding \Nthese barnacles
Dialogue: 0,0:08:38.55,0:08:41.23,Default,,0000,0000,0000,,they are limited to the area
Dialogue: 0,0:08:41.83,0:08:44.91,Default,,0000,0000,0000,,that is covered by water for much \Nof the day.
Dialogue: 0,0:08:45.75,0:08:50.63,Default,,0000,0000,0000,,They have a much lower tolerance \Nfor drying out than the barnacles do.
Dialogue: 0,0:08:51.15,0:08:52.88,Default,,0000,0000,0000,,And so we see this very distinct,
Dialogue: 0,0:08:52.88,0:08:55.02,Default,,0000,0000,0000,,what's called a zonation line,
Dialogue: 0,0:08:56.33,0:08:58.82,Default,,0000,0000,0000,,that's separating the mussels and the \Nbarnacles
Dialogue: 0,0:08:58.82,0:09:01.77,Default,,0000,0000,0000,,because barnacles can live in those\Nhigher, inner tidals
Dialogue: 0,0:09:02.08,0:09:04.94,Default,,0000,0000,0000,,where there is less wave splash, \Nbut mussels can't survive.
Dialogue: 0,0:09:05.47,0:09:08.43,Default,,0000,0000,0000,,So this is a good example of resource \Npartitioning.
Dialogue: 0,0:09:09.38,0:09:13.80,Default,,0000,0000,0000,,The mussels have excluded the barnacles\Nfrom the--the wet zone down here
Dialogue: 0,0:09:14.60,0:09:18.10,Default,,0000,0000,0000,,but he barnacles, because they can last\Na little bit longer out of water,
Dialogue: 0,0:09:18.45,0:09:22.52,Default,,0000,0000,0000,,have been able to engage in resource \Npartitioning and use this space up
Dialogue: 0,0:09:22.52,0:09:24.00,Default,,0000,0000,0000,,in the high inner tidal.
Dialogue: 0,0:09:24.86,0:09:26.30,Default,,0000,0000,0000,,What's kind of exciting
Dialogue: 0,0:09:27.90,0:09:31.60,Default,,0000,0000,0000,,is that if mussels are removed in some way
Dialogue: 0,0:09:33.31,0:09:35.10,Default,,0000,0000,0000,,then barnacles will spread
Dialogue: 0,0:09:35.42,0:09:37.00,Default,,0000,0000,0000,,to fill the available space.
Dialogue: 0,0:09:37.24,0:09:40.03,Default,,0000,0000,0000,,So perhaps we have a sea star predator \Nthat comes up here,
Dialogue: 0,0:09:41.08,0:09:42.96,Default,,0000,0000,0000,,removes and eats the mussels,
Dialogue: 0,0:09:43.68,0:09:46.40,Default,,0000,0000,0000,,barnacles will then spread to fill \Nthat available space
Dialogue: 0,0:09:46.40,0:09:48.86,Default,,0000,0000,0000,,and this is known as \N"competitive release."
Dialogue: 0,0:09:49.54,0:09:52.96,Default,,0000,0000,0000,,Basically if a superior competitor \Nis removed
Dialogue: 0,0:09:54.34,0:09:58.23,Default,,0000,0000,0000,,then the other competitor may take \Nadvantage of that better resource.
Dialogue: 0,0:09:58.67,0:10:00.92,Default,,0000,0000,0000,,They don't have to resource partition \Nanymore.
Dialogue: 0,0:10:02.40,0:10:06.57,Default,,0000,0000,0000,,And so this the reason that sea stars\Nare, themselves, considered a keystone
Dialogue: 0,0:10:06.57,0:10:08.53,Default,,0000,0000,0000,,species on the Oregon Coast
Dialogue: 0,0:10:09.02,0:10:10.95,Default,,0000,0000,0000,,and throughout the Pacific Northwest
Dialogue: 0,0:10:10.95,0:10:15.03,Default,,0000,0000,0000,,because they wipe out big mussel \Npopulations and allow other kinds of
Dialogue: 0,0:10:15.03,0:10:16.96,Default,,0000,0000,0000,,organisms to live in the inner tidal.
Dialogue: 0,0:10:17.71,0:10:20.12,Default,,0000,0000,0000,,So, competition has a really big \Ninfluence here,
Dialogue: 0,0:10:20.62,0:10:24.34,Default,,0000,0000,0000,,but if our sea star comes along and \Nremoves that superior competitor,
Dialogue: 0,0:10:24.70,0:10:26.10,Default,,0000,0000,0000,,it changes the community--
Dialogue: 0,0:10:26.11,0:10:29.26,Default,,0000,0000,0000,,making the sea star another example\Nof a keystone species.
Dialogue: 0,0:10:31.69,0:10:35.89,Default,,0000,0000,0000,,And you can see that here in this \Nactual picture of the, um, these sea stars
Dialogue: 0,0:10:35.89,0:10:38.84,Default,,0000,0000,0000,,that come up to a certain level of the \Ninner tidal
Dialogue: 0,0:10:39.13,0:10:41.51,Default,,0000,0000,0000,,they've eaten a whole bunch \Nof these mussels.
Dialogue: 0,0:10:42.78,0:10:45.15,Default,,0000,0000,0000,,Remember from our example of\Nco-evolution,
Dialogue: 0,0:10:45.15,0:10:49.76,Default,,0000,0000,0000,,sea stars are great at eating shellfish\Nbecause they pry open that shell
Dialogue: 0,0:10:49.76,0:10:50.80,Default,,0000,0000,0000,,just a little bit
Dialogue: 0,0:10:50.80,0:10:54.85,Default,,0000,0000,0000,,and push their stomachs inside out and\Ninside that shell and--and dissolve those
Dialogue: 0,0:10:54.85,0:10:57.14,Default,,0000,0000,0000,,nutrients in there and then\N[clicks tongue]
Dialogue: 0,0:10:57.14,0:10:59.24,Default,,0000,0000,0000,,pull their stomachs back into their \Nbodies.
Dialogue: 0,0:10:59.91,0:11:04.17,Default,,0000,0000,0000,,So, here they have created this \Nline of mussels and if you look below
Dialogue: 0,0:11:04.17,0:11:07.34,Default,,0000,0000,0000,,the mussel line you can see all these\Ndifferent kinds of seaweed,
Dialogue: 0,0:11:07.34,0:11:09.20,Default,,0000,0000,0000,,there's some other shells downs here,
Dialogue: 0,0:11:09.20,0:11:10.11,Default,,0000,0000,0000,,some barnacles.
Dialogue: 0,0:11:10.11,0:11:12.46,Default,,0000,0000,0000,,And they have really changed the \Ncommunity.
Dialogue: 0,0:11:13.56,0:11:16.73,Default,,0000,0000,0000,,And we have different populations \Ntaking part in that community.
Dialogue: 0,0:11:16.82,0:11:17.99,Default,,0000,0000,0000,,We have mussels,
Dialogue: 0,0:11:17.99,0:11:19.42,Default,,0000,0000,0000,,we have sea stars,
Dialogue: 0,0:11:19.62,0:11:21.11,Default,,0000,0000,0000,,we have barnacles,
Dialogue: 0,0:11:21.11,0:11:22.56,Default,,0000,0000,0000,,we have algae,
Dialogue: 0,0:11:22.56,0:11:24.30,Default,,0000,0000,0000,,all of those populations,
Dialogue: 0,0:11:24.30,0:11:27.11,Default,,0000,0000,0000,,all the members of a species that are \Nliving together in a place
Dialogue: 0,0:11:27.11,0:11:28.59,Default,,0000,0000,0000,,are interacting...
Dialogue: 0,0:11:29.11,0:11:30.50,Default,,0000,0000,0000,,in this community.
Dialogue: 0,0:11:30.50,0:11:31.92,Default,,0000,0000,0000,,And what we are going to see
Dialogue: 0,0:11:31.92,0:11:33.64,Default,,0000,0000,0000,,is that competition
Dialogue: 0,0:11:33.64,0:11:36.09,Default,,0000,0000,0000,,can occur between members of a \Ncommunity.
Dialogue: 0,0:11:36.66,0:11:38.74,Default,,0000,0000,0000,,Like a lion and a crocodile.
Dialogue: 0,0:11:40.41,0:11:44.03,Default,,0000,0000,0000,,And, in this case, what are a lion and \Na crocodile gonna compete for?
Dialogue: 0,0:11:44.12,0:11:46.54,Default,,0000,0000,0000,,Well, they're certainly competing for \Nfood.
Dialogue: 0,0:11:46.54,0:11:49.52,Default,,0000,0000,0000,,But, they may not be competing for \Nall of the same things.
Dialogue: 0,0:11:50.05,0:11:52.70,Default,,0000,0000,0000,,So here we have niche overlap that is \Njust partial .
Dialogue: 0,0:11:52.78,0:11:54.80,Default,,0000,0000,0000,,In this case, the lion and the crocodile
Dialogue: 0,0:11:54.80,0:11:57.19,Default,,0000,0000,0000,,they're not competing for the same \Nplace to live;
Dialogue: 0,0:11:57.19,0:12:00.30,Default,,0000,0000,0000,,the crocodile prefers an aquatic \Nenvironment, the lion does not.
Dialogue: 0,0:12:00.30,0:12:02.36,Default,,0000,0000,0000,,They're certainly not competing for mates.
Dialogue: 0,0:12:03.60,0:12:04.67,Default,,0000,0000,0000,,However...
Dialogue: 0,0:12:05.26,0:12:10.40,Default,,0000,0000,0000,,lions are going to have 100% niche overlap\Nwith other members of the same species.
Dialogue: 0,0:12:11.25,0:12:16.05,Default,,0000,0000,0000,,And so competition tends to be much \Nmore intense between members
Dialogue: 0,0:12:16.05,0:12:17.63,Default,,0000,0000,0000,,of the same species.
Dialogue: 0,0:12:17.63,0:12:21.21,Default,,0000,0000,0000,,That's the difference between \Ninterspecific competition:
Dialogue: 0,0:12:21.21,0:12:24.61,Default,,0000,0000,0000,,competition that takes place between \Nmembers of a different species
Dialogue: 0,0:12:25.44,0:12:30.73,Default,,0000,0000,0000,,and intraspecific competition that takes\Nplace between members of the same species.
Dialogue: 0,0:12:31.37,0:12:34.03,Default,,0000,0000,0000,,And the real difference here is \Ncomplete niche overlap.
Dialogue: 0,0:12:34.46,0:12:35.90,Default,,0000,0000,0000,,If you're in the same species
Dialogue: 0,0:12:35.90,0:12:37.56,Default,,0000,0000,0000,,you're competing for food,
Dialogue: 0,0:12:37.56,0:12:38.73,Default,,0000,0000,0000,,for living space,
Dialogue: 0,0:12:38.73,0:12:39.80,Default,,0000,0000,0000,,for mates,
Dialogue: 0,0:12:39.80,0:12:41.67,Default,,0000,0000,0000,,because you have the exact same needs.
Dialogue: 0,0:12:41.67,0:12:45.30,Default,,0000,0000,0000,,So one of the things that we see with \Ncompetition that's really interesting
Dialogue: 0,0:12:45.30,0:12:51.10,Default,,0000,0000,0000,,is that intraspecific competition tends to\Nbe the most intense competition
Dialogue: 0,0:12:51.29,0:12:53.15,Default,,0000,0000,0000,,and is going to be much more intense,
Dialogue: 0,0:12:53.15,0:12:54.04,Default,,0000,0000,0000,,in many cases,
Dialogue: 0,0:12:54.04,0:12:56.21,Default,,0000,0000,0000,,than interspecific competition.
Dialogue: 0,0:12:59.57,0:13:03.87,Default,,0000,0000,0000,,We are going to be focusing more next\Nweek on other kinds of dynamics that
Dialogue: 0,0:13:03.87,0:13:05.32,Default,,0000,0000,0000,,influence the shape,
Dialogue: 0,0:13:05.32,0:13:07.24,Default,,0000,0000,0000,,and size of these pop...
Dialogue: 0,0:13:09.24,0:13:13.70,Default,,0000,0000,0000,,We are going to be looking in much \Nmore detail next week at other kinds
Dialogue: 0,0:13:13.70,0:13:17.96,Default,,0000,0000,0000,,of interactions that influence the shape\Nand size of these populations.
Dialogue: 0,0:13:19.15,0:13:25.04,Default,,0000,0000,0000,,In the meantime, don't forget to do the \N"Battle At Krueger" online exercise for
Dialogue: 0,0:13:25.04,0:13:28.66,Default,,0000,0000,0000,,your 5 activity points\Nand to also participate in the discussion
Dialogue: 0,0:13:28.66,0:13:31.58,Default,,0000,0000,0000,,forum for this week where you can ask\Nand answer questions.
Dialogue: 0,0:13:31.80,0:13:34.63,Default,,0000,0000,0000,,I will also be asking and \Nanswering questions
Dialogue: 0,0:13:34.63,0:13:38.66,Default,,0000,0000,0000,,and that is going to help us \Nkeep up on these community interactions.