Chapter 54: Community Ecology Flashcards
What is biodiversity?
The variety of life across all levels of biological organization
- genetic diversity
- species diversity
- ecosystem diversity
What is genetic diversity?
Varying genes that make up the characteristics of a species
What is species diversity?
Number of different species in a particular region
Two parts:
Species richness
Species evenness
What is ecosystem diversity?
Variety of habitats and communities in the world
What is species richness?
The number of species
What is species evenness?
The relative abundance of the species in that environment
How many there are for that environment
Answer the following for each location:
a) What is the species richness?
b) What is the species evenness?
Location 1:
- One tree
- Nine of the same shrub
Location 2:
- Five of the same tree
- Five of the same shrub
Location 1:
a) Species richness = 2
b) Species evenness = low
Location 2:
a) Species richness = 2
b) Species evenness = high
What does the Berger-Parker Index say about diversity?
The sample with greater evenness is more diverse than the sample with greater richness
How are community interactions classified?
By whether they help, harm, or have no effect on the species involved.
What are the 4 community interactions?
- Competition
- Predation
- Herbivory
- Symbiosis
- parasitism
- mutualism
- commensalism
What is competition?
When two or more species try to obtain the same limited resources
What is predation?
An interaction between species where the predator kills the prey
What is herbivory?
When plants are consumed by animals
What is symbiosis?
When individuals of 2 or more species live in direct and intimate contact with one another
What is parasitism?
When one organism feeds on the other (host)
- host receives no benefit
What is mutualism?
When both individuals benefit from the relationship
E.g., ants feed off of acacia plants for nutrients, and the acacia plants are protected by the ants.
What is commensalism?
An interaction in which one species benefits and the other is neither benefited or harmed
E.g., birds nest in trees, tree is not benefited or harmed.
What are hitchhiking species?
Species that partake in commensalism on the go.
E.g., algae on turtle shells, barnacles on whales etc.
Does competition have a positive or negative effect on both species?
Negative on both
Does predation have a positive or negative effect on both species?
Positive for the predator
Negative for the prey
Does parasitism have a positive or negative effect on both species?
Positive for the parasite
Negative for the host
Does mutualism have a positive or negative effect on both species?
Positive on both
Does commensalism have a positive or negative effect on both species?
Positive for one species
Neither +/- for other
What is the competitive exclusion principle?
Principle which states that the species that acquires more of the resources will win and the other species will die out
How are species able to coexist?
Both species will confine themselves to a particular niche in the same environment
E.g., there are two types of barnacles. Barnacle type 1 lives on the part of the rock that receives high tide. Barnacle type 2 lives on the part of the rock gang receives low tide. If barnacle type 2 was absent, barnacle type 1 would cover the entire rock, however, they are coexisting together.
What is resource partitioning?
When similar species focus on different resources/niches in order to coexist in a community
E.g., multiple bird species can live in the same tree. Some with live at the top of the tree while another lives in the middle.
What is character displacement?
When a species in a habitat will diverge because competing for a specific niche has restricted them to specific resources
What are 4 characteristics that prey can do in order to prevent themselves from being eaten?
Camouflage
Warning coloration
Chemical defenses
Mimicry
What is cryptic coloration?
Camouflage, where the organisms appearance can blend in with a background.
What is warning coloration?
Aposematic coloration
When an organism will physically change its color in order to show or pretend it is venomous to frighten the predator away
What is mimicry?
When an organism pretends to be another in order to deter predators
What is Batesian mimicry?
When a species evolves to resemble a species that has superior, protective capability.
In Batesian mimicry there are 3 players: the model, the mimic, and the dupe. How does each one play?
The model is the species with the superior, protective capability.
The mimic is the species pretending to be the model.
The dupe in the predator fooled into believing that the mimic is the model.
What is a habitat?
The physical surroundings in which a species can normally be found
What is a niche?
All of the resources required for the survival, growth, and reproduction of a species.
- light, temperature and chemicals are also part of the niche
What is a keystone species?
A species who’s a sense from a community would bring about significant change.
- not every community has a keystone species
