Interaction between Interaction between SpeciesSpecies

A closer look…A closer look…

First, a reviewFirst, a review

What is carrying capacity?What is carrying capacity? How big a population can get while still being How big a population can get while still being

supported, having enough resourcessupported, having enough resources How can you increase carrying capacity?How can you increase carrying capacity?

Altering ecosystem so more energy, Altering ecosystem so more energy, resources are availableresources are available

Altering behaviourAltering behaviour

Copy this downCopy this down Humans have altered the ecosystems that Humans have altered the ecosystems that

support us, so the carrying capacity is highsupport us, so the carrying capacity is high

But, modern human societies are still subject to But, modern human societies are still subject to the ecological principle of carrying capacitythe ecological principle of carrying capacity

Human growth has rapidly accelerated over the Human growth has rapidly accelerated over the past 400 yearspast 400 years With a current doubling time of less than 1 human With a current doubling time of less than 1 human

lifetimelifetime

Human Population GrowthHuman Population Growth

Ecological FootprintEcological Footprint

Def: an estimate of how much land and Def: an estimate of how much land and water required to support someone’s water required to support someone’s lifestylelifestyle

What is your ecological footprint?What is your ecological footprint? Mine is 6Mine is 6

Urban SprawlUrban Sprawl

A city’s growth as it’s population increasesA city’s growth as it’s population increases More and more development on the ‘outskirts’ of a More and more development on the ‘outskirts’ of a

citycity

The Golden HorseshoeThe Golden Horseshoe

West end of Lake Ontario

Interaction Among SpeciesInteraction Among Species

Resources and abiotic factors are not the Resources and abiotic factors are not the only influences on a populationonly influences on a population

Organisms interact with each other tooOrganisms interact with each other too

Ecological NicheEcological Niche

Species focus onSpecies focus on1.1. SurvivingSurviving

2.2. ReproducingReproducing They do not have jobs, but they do They do not have jobs, but they do

contribute a ‘role’contribute a ‘role’ Provide benefits to the ecosystemProvide benefits to the ecosystem

Def: the role an organism plays within its Def: the role an organism plays within its ecosystem (biotic and abiotic factors)ecosystem (biotic and abiotic factors)

Ecological NicheEcological Niche

Sample nichesSample niches Regulation of a population (like insects)Regulation of a population (like insects) Decomposition of dead matterDecomposition of dead matter Cycling of matterCycling of matter

There are millions of spots on EarthThere are millions of spots on Earth There are millions of niches tooThere are millions of niches too

Carnivorous PlantsCarnivorous Plants

Predation and Population SizePredation and Population Size

Predators and prey influence one Predators and prey influence one another in 2 waysanother in 2 ways

1.1. Bottom-up population regulationBottom-up population regulation

2.2. Top-down population regulationTop-down population regulation

#1

Bottom-up population regulationBottom-up population regulation

Grasshoppers eat grass; shrews eat Grasshoppers eat grass; shrews eat grasshoppersgrasshoppers

GrassGrassGrasshopperGrasshopperShrewShrew If the grasshoppers eat too much grass, If the grasshoppers eat too much grass,

population could decrease due to lack of population could decrease due to lack of food.food.

If the population of grasshoppers If the population of grasshoppers decreases, there is not enough food for decreases, there is not enough food for shrews shrews their population decreases their population decreases

Bottom-up population regulationBottom-up population regulation

This is called… This is called… … because there is … because there is a shortage in the plant resource at the a shortage in the plant resource at the basebase of the food chain which affects of the food chain which affects animals in higher trophic levelsanimals in higher trophic levels

Top-down population regulationTop-down population regulation

Now consider this…Now consider this… What if the population of rabbits increases?What if the population of rabbits increases?

With more rabbits to eat, coyote population With more rabbits to eat, coyote population increasesincreases

But with more coyotes eating rabbits, the rabbit But with more coyotes eating rabbits, the rabbit population will decreasepopulation will decrease

This is top-down regulation because a This is top-down regulation because a higher (top)higher (top) trophic level organism influences the population of trophic level organism influences the population of a lower trophic levela lower trophic level (eventually the # of coyotes would decrease too)(eventually the # of coyotes would decrease too)

CompetitionCompetition

As the population of a As the population of a species increases, so species increases, so does the competition does the competition for resourcesfor resources Can limit population sizeCan limit population size The more energy an The more energy an

organism spends organism spends competing, the less competing, the less energy it has for growth energy it has for growth and reproductionand reproduction

#2

SymbiosisSymbiosis

The interaction The interaction between members of between members of 2 different species 2 different species that live together in that live together in close associationclose association

2 types of symbiosis2 types of symbiosis1.1. MutualismMutualism

2.2. ParasitismParasitism

#3

MutualismMutualism

Def: symbiotic relationship between 2 species Def: symbiotic relationship between 2 species where both benefitwhere both benefit Ex: clownfish and anemonesEx: clownfish and anemones

In symbiotic mutualism, the clownfish feed on small invertebrates which otherwise could potentially harm the sea anemone, and the fecal matter from the clownfish provides nutrients to the sea anemone. The clownfish is additionally protected from predators by the anemone's stinging cells, to which the clownfish is immune.

ParasitismParasitism

Def: symbiotic relationship between 2 species Def: symbiotic relationship between 2 species where 1 organism (where 1 organism (parasiteparasite) depends on another ) depends on another larger organism (larger organism (hosthost)) Frequently the parasite benefits at the host’s expenseFrequently the parasite benefits at the host’s expense

These primitive fish attach to the bodies of native fish and feed on the fish's body fluids. This often leads to the death of the native fish. Species at risk in the Great Lakes include prized commercial and recreational species such as lake trout, salmon, rainbow trout (steelhead), whitefish, walleye and catfish.

Brain WormBrain Worm

1.1. Worm lays eggs in brainWorm lays eggs in brain

2.2. Eggs travel to lungs and hatchEggs travel to lungs and hatch

3.3. Larval worms excretedLarval worms excreted

4.4. Eaten by slugsEaten by slugs

5.5. Eaten by deerEaten by deer

White-tailed deer White-tailed deer aren’t affectedaren’t affected Brain-worm cycle Brain-worm cycle

successfulsuccessful

Other animals are Other animals are very vulnerablevery vulnerable Moose diseaseMoose disease SheepSheep Elk Elk CaribouCaribou

Human ParasitismHuman ParasitismA 28-year-old medical resident and a companion returned from hiking in Central America with pruritic, erythematous, single-track linear and serpiginous lesions located predominantly on their lower extremities. A physician clinically examined the skin disorder and diagnosed the two patients with cutaneous larva migrans after learning that they had been walking barefoot on the beach during their vacation.

Cutaneous larva migrans (CLM) was first described as "the creeping eruption" and diagnosed by a physician in 1874. Today, it is one of the most common hookworm infections acquired from subtropical and tropical regions of the world.