Cycle 10: Cooperation and Conflict Flashcards
Intraspecific Vs Interspecific Interactions
Intraspecific interactions: Interactions between individuals of the same species
Interspecific interactions: Interactions between individuals of different species
What is one thing in common with all organisms?
They all want RESOURCES (food, mates, territory etc.)!
When we study ecology, we look at how the organisms interact with their environment. If there’s one thing in common with all organisms, it’s that every single organism needs resources such as food, mates, territory etc. and this inevitably leads to competition for these resources. When populations are high, there is more competition and when populations are low, there is less competition.
Interference/Contest Competition
Dangerous Competition
Think of this type of competition as dealing with gatekeepers. This is where one organism has the resource, and another organism will fight the organism with the resource to take it. This type of competition is dangerous! Either party has a chance of getting hurt. For example, if you have the resource, then you’ll get attacked and might get hurt. But also because you’re the one with the resource, maybe you have it because you’re stronger than the others, and you’ll hurt the other individuals that attack you. Creosote bushes have deep roots so they access the deeper layers of soil water. The problem arises when we have little rain, the shallow rooted plants will access the water before the water reaches the deeper soil layers. So, to fight for the resource of water, these bushes will release toxic chemicals which will then prevent plants from growing nearby.
Exploitation/Scramble Competition
2 or more organisms that will use the same resource, but there’s always going to be one organism that’s going to use up the resource more than the others.
Think this type of competition as a free for all but with no physical fighting. This is where we have 2 or more organisms that will use the same resource, but there’s always going to be one organism that’s going to use up the resource more than the others. A great example would be your siblings! Think of when you and your sibling share food, usually one of you ends up taking more than the other. That’s scramble competition.
Competition for Resources: Food
(difference between interspecific and intraspecific)
In nature, we often see competition for 3 resources: Food, Territory, and Mates.
Starting off with food, we have intraspecific competition for food which is organisms within the same species competing for food. Whoever eats the fastest will get more of the resource and grow bigger. So that’s you and your human friend competing for steak.
On the other hand, we have interspecific competition for food which is organisms of different species competing for food. This time, it’s you and your dog competing for steak.
Competition for Resources: Territory
((difference between interspecific and intraspecific)
Next we look at competition for territory. Let’s take a look at an example you talked about in class: red-wing blackbirds.
The male red-wing blackbirds are very territorial. They will perch on top of trees and fend off against the other male red-wing blackbirds. It’s intraspecific since he’s fending off males of his own species.
There have been cases where these male red-wing blackbirds will chase out larger animals like horses. It’s interspecific competition since it’s between different species.
Competition for Resources: Mates
(difference between interspecific and intraspecific)
Example: Japanese Beetles where we have the females emitting pheromones which will attract many males to crowd onto her to try to mate with her.
Symbiosis
A close and long term association between 2 species
Mutualism (+/+)
Both species benefit from the association
Predation (+/-)
Only one species benefits from the association and the prey is injured or killed.
2 Strategies: Sit and Wait Strategy; Active Pursuit strategy
Commensalism (+/0)
One species benefits from the association but the other is unaffected
Parasitism (+/-)
This is where only one species benefits from the association between the parasite and the host. (+/-) Parasites affect the fitness of the host, but don’t result in its direct death since they’re not going to want to bite the hand that feeds them. If the host dies, the parasite dies too so killing the host would be a bad idea for parasites.
Herbivory (+/-)
This is similar to parasitism but between herbivores and plants. (+/-) The herbivore will affect the fitness of the plant it’s eating, but also doesn’t kill it.
Simple (Direct) Life Cycle
1 Parasite, 1 Host
When a parasite species uses ONE host species to complete their life cycle and survive.
E.g. Mistletoe
Ectoparasite: Parasitic plant
Roots penetrate into tree
Can exploit OR provide nutrients (i.e. water)
E.g. Tapeworms
Endoparasite (Endo = INSIDE)
Lives in the intestine
Shed segments full of eggs that, once ingested, can infect a new host
Complex (inDirect) Life Cycle
1 Parasite, MULTIPLE Hosts
When a parasite species uses AT LEAST 2 different host species to complete their life cycle and survive.
E.g. Schistosomiasis
1) Schistosoma eggs are eliminated with feces or urine, depending on species (i.e. infected human)
2) These eggs will hatch and penetrate specific snails hosts → these are your intermediate hosts
3) Developed parasitic snail hosts are released are free-swimming
4) Penetrates skin of human host
5) Circulate to the lungs → heart → develops in the liver
6) Eliminated with feces or urine → process is repeated
Parastoids
When an adult is free living, but its offspring develop in OR on the host and kill it.
Example: Tomato Hornworms and Parasitic Wasps. As the eggs hatch, the larvae feeds on the insides of the hornworms. Adult wasps will emerge from the cocoons and the hornworm will die.
