Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 4: Ecology Part 2 - Coggle Diagram
Chapter 4: Ecology Part 2
Population dynamics:
Population: Reproducing species in a certain area.
How to understand wildlife populations?
Need to examine:
Pattern of change equation. Change in population=(Birthing +immigration)-(Death + emigration).
Carrying capacity (K): Upper Limit of an species an ecosystem can hold.
Ecologists analyze populations with models:
Population growth curves:
Constant.
Exponential (J-Curve)
Logistic growth (S-Curve)
Why might population growth slow after a large increase?
Approaching carrying capacity which can be due to too many species thus leading to too
Few resources,
Lack of space,
Predator adaptation/attraction,
Disease,
Competition.
Biotic potential: Number of offspring under ideal conditions.
Environmental Resistance: Biotic vs. abiotic factors cause mortality and limit population increase.
If species survives through early growth stages->recruited into breeding population.
Reproductive strategies. R vs K strategies:
R: Many offspring, generally tend to be smaller, less parental care, lifespan tends to be shorter, unstable population, young onset for reproduction.
K: Few offspring, generally tend to be larger, more parental care, tend to have a longer lifespan, stable population, older age for reproduction.
In between is R-K.
Limits on Population:
Density: individual species/unit area
Density dependent: limits increases as population density increases.
Density independent: population limited by abiotic factors regardless of numbers.
Top down regulations vs. bottom up regulation
Top down regulation: control population by predation.
Bottom up regulation: control of population due to resource scarcity.
Critical number: minimum population for a species to survive in the environment.
Sharp decline=threatened.
Below critical number=endangered classification.
Extinction=species no longer exists in the wild.
Community interaction types:
Symbiosis: two species’ lives are connected (positive or negative)
Predation: one species benefits and other is harmed. (Mountain lion and deer)
Predatory, herbivory, parasitic. (Athlete’s foot)
Competition: two organisms (same species or different) relying on the same resource. Intraspecific: competition for resources between the same species. Interspecific: competition for resources between different species. Typically results in resource partitioning.
Mutualism: both species benefit. (Water Buffalo and egret)
Commensalism: One species benefits and the other is unaffected.(Water Buffalo and egret)
Amensalism: One species unaffected and the other is harmed. (Livestock trampling over grass)
Neutralism: Neither species are harmed or benefited. (Coexisting)
Evolution:
Evolution occurs through adapting to environmental factors.
Predation and competition.
Favor survival of individuals that lower impacts of negative interactions.
Predators and prey can adapt to one another.
Selective pressure: Environmental resistance factors.
Selective pressure: Environmental resistance factors.
Natural selection: Process of specific traits favoring survival of certain individuals.
Process discovered independently by Charles Darwin and Alfred Wallace.
Island biogeography theory:
Extinct.
Speciation due to natural selection which leads to evolution.
Colonized from elsewhere.