Test 2 Flashcards
Group of the same species…
Living in the same place, same time, and able to interbreed/intergrade successfully (make offspring)
Demographics…
The study of populations
Populations are described by…
Size - # of organisms
Density - # per unit area
Dispersion - How these #’s per area are distributed.
Dispersion types…
Even - Low density; territorial. High density; avoid competition
Random - Wind dispersed; seeds/warms
Clumped - Herding and organized colonies (warmth, resources, protection, etc.)
Survival of population…
Fitness - Ability to reproduce successfully
Survivorship- Lifespan overtime
Limits to resources
Fitness (reproduce strategy’s)…
“r” strategists:
- Rapid reproduction, fast pregnancy, quick life cycle
- High reproductive rate
-Less parental involvement
“k” strategists:
- Slow reproduction, long pregnancy, slow life cycle
- Lower reproductive rate
- Long parental involvement
Recipe for survival…
Requires resources
- Carrying capacity: Total # of organisms that an environment can sustain
- Limiting factor: The 1 thing that limits this population
Growth models…
Exponential growth - J-curve (fast growth)
“r” strategists
Logistic growth - S-curve (grows a little slower)
“k” strategists
Exponential growth - G=RN, G = growth rate, N = # of individuals in a population, R = reproduction rate
Factors that limit population growth…
Density dependent:
- Resources competition
- Health & disease
- Predators/Prey
- Stress
Density independent:
- Weather & seasonal changes
- Natural disasters
Resources partitioning…
The division of limited resources by species to help avoid competition in an ecological niche
Biodiversity…
Richness - # of different species
Relative abundance (species evenness) - # of organisms of each species
Dominant species/ keystone species
Exerts strong control over the community structure from the top down (dominant) and all directions (keystone)
Competitive exclusions principle eliminates competition benefiting all
Response to disturbance…
Succession - evolution of ecosystems
Change in ecosystem due to competition and attrition
Dominant species of the climax community
Trophic structure…
Feeding relationships between produces, consumers, and detrivores
Niches…
Role or job an organisms plays in the environment
Generalist (niche)
Can make use of a wide variety of resources (humans)
Specialist
Limited on use of resources (panda bear, koalas)
Fundamental (niche)
Range of resources that you could ideally use (adapted to; evolution)
Realized (niche)
The range of resources that you can actually gain access to (acclimated to; used to)
Gause’s competitive exclusion principle
States that two species competing for the same resources cannot exist
Which is false
Symbioses
Close interactions that tie population together as communities
Trophic levels - feeding structure
- Producers from the basis
- Consumers “eat” those below them
- Only 10% - 20% of one level is passed on to the next level
- Up to 90% of the energy available at one level is lost to other levels as heat
Amensalism
- , 0
Competition
- , -
