Ecology 5- Community Ecology Flashcards
What is a community
Made up of populations of organisms that occur together in the same environment and interact with each other
What is diversity
Includes both species richness (i.e. composition) and species abundance (eveness / distribution )
What is composition
A listing of various species in the community
What are the fundamental characteristics of a community
Compositon; Richness and diversity
Explain community structure
- Changes as a result of interactions between populations
These interactions include:
- Competition
- Predation
- Parasitism
- Commensalism
- Mutualism
- Amensalism
Explain richness
Number of different species
Explain measuring species richness
- Uses samples to estimate
- Number of species depends on sampling size
- Plot a species vs area curve
- when it drops off = good job sampling
Eplain richness and abundance = diversity scenario : 1. Community of 100 individuals and 10 species and each species has 10 individuals.
- A community of 100 individual is made up of nine species having one individual each and one species having 91 individuals
1 = Diverse community ( equal number of individuals )
2 = Non-diverse 9 ( high species richness but less diverse )
Explain a healthy community
- Helathy community = diverse community
- Not dominated by one species
Explain species composition
- In general, species richness increases with decreasing latitude
( Increases from poles to tropics )
- More sun at equator thus plants have more energy to photosynthesis thus more resources and habitats
Explain predation
- AKA predator-prey interaction
+- relationship
- Abundance of predator incr while prey decr
Explain competition
( - - ) interaction
- Abundance of both species decreases
Explain commensalism
- Is a + 0 relationship
- One benefits but other doesnt benefit or suffer
Explain Ammenslism
-0 interaction
- One suffers from interaction but other neither benefits or suffers
Explain what is habitat
- The physical place where an organism lives and reproduces
- Each habitat has a characteristic range of physical and chemical conditions, such as the amount of light,(above canopy vs below canopy); temperature; pH of water,etc.
Explain Habitat and Ecological Niche
- Each species is adapted to the conditions of its habitat in terms of :
- morphology,
- physiologyand
- behaviour
Explain Ecological Niche
- Ecological niche is the full range of conditions under which an organism can survive and reproduce
- It is the role an organism plays in its environment
Includes both:
1. Habitat
2. Interactions with other organisms
What is ecological niche split into
Fundamental and realized niche
Explain the fundamental niche
Entire set of conditions under which the organism can potentially survive and reproduce
Explain realised niche
Set of conditions under which it exists in nature
What factors force a population to occupy its realised niche
Biotic niche
Explain interspecific competition
- When different species share resources that are limited, the species must compete with each other
- This has a negative impact on one or both species
Example: barnacles and mussels compete for space on a rock
Explain Competitive Exclusion
- States that no two species can occupy the same niche at the same time
- If two species occupy the same or similar niches, eventually one species will out- compete the other, which will die out
Explain Resource Partitioning
Species that share the same resources can coexist if their niches are slightly different
Explain character development
- When a particular character is more divergent (different) when two populations belong to the same community than when they do not
- They can live in the same region (sym- meaning “together”, plus patria, gives sympatry),
- Or they can live in different regions (allo- meaning “other”, plus patria gives allopatry)
eg ) Galapagos finches
When is resource partitioning NOT resource partitioning?
Species evolve differences in how they exploit those resources in order to reduce competition and make coexistence possible
