Populations & Sustainability Flashcards
animals and how they act out in nature basically....
What is the Lag, Log and Stationary Phases of Pop. Growth graph?
- Lag = rate of reproduction AND growth rate will be low
- Log = plentiful resources, much faster rate of reproduction exeeding mortality rate, exponential increase
- Stat = rate of reproductive and mortality rate will be EQUAL, cant support larger pop.
Define Carrying Capacity?
- max population size mantained over tmie in a habitat!!
Difference with density dependant and density independant Limiting Factors!
- dep = limiting factor affected STRONGLY by population sizes, e.g. pathogens; competition; predation
-
indep = limiting factor NOT AFFECTED by population sizes, e.g. tempratures; climate changes
LIMITING FACTOR = something limiting growth of pop.
Define, Example and State Differences with K-Strategists and R-Strategists!
= represents 2 different strategies adopted by living organisms
1. K»_space; species which poplation is determined by carrying capacity, LIMITING FACTOR take more significant effect as population gets closer to carrying capactiy, low reproductive rate/long lifespan/large body mass
2. R»_space; pop can increase very fast, exceeding carrying capacity via boom, where lack of resources and food causes decline in population, excess waste can posion pop, with high reproductive rate/short lifespan/small body mass
K = elephants, pandas, Birds
R = insects, mice, weed plants
Malthusian Carastrophes….
Why would Predator-Prey cycles by more complex in nature than a lab reading?
- Nature may have other speices that may also predate on same prey
- multiple factors may also act as limiting factor [O2 conc/Habitat availability]
- Single predator may consume more animals than other predators
How can we describe Predator-Prey cycles
- can be describe as having a negative feedback
- As prey increases, greater food abundance for predators, hence both will increase
- as predators increase, more prey will eaten, so prey decrease
- lack of food for predators again causes decrease, and prey starts to thrive and cycle starts ALL OVER..
State and Explain are the 2 types of competition in animals
- Intraspecific = competition WITHIN same species, with relitavly stable pop. sizes, as food/resources become limiting, species die, plentiful again and increase!
- Interspecific = individuals with DIFFERENT species, one species normally OUTCOMPETING the other species/ 1 species with much lower pop. size than other… due to competative exclusion principle
What is the Competative Exclusion Principle?
- If 2 species occupy exacly the same niche, one will outcompete the other, as 2 species CAN NOT OCCUPY AND THRIVE in EXACTLY SAME NICHE!!
Methods to conserve certain Ecosystems…?
- Terai Region-Nepal = alternate sources of fuel, other than environment dependant (solar-cookers/Biofuel generators)
- Masai Mara-Kenya = Ecotourism, while farming in a controlled, sustainable manner
- Peat Bogs-UK= Government funded programmes to encourage sustainable use, or banning use of peat..
How may human activities affect a population of ecosystem, and how to STOP IT?
- Introducing Invasive Species: Humans may bring non-native species in an area, may increase competition over resources = struggle to survive » Undergo culling programmes and increased survaillance to prevent invasive species
- Hunting: decreases wildlife population Predator-Prey cycles » banning and surveillance
- Erosion: footpath erosion, trampling and destroying vegetation via unmarked routes » visitor education on footpaths, and mantainance undertaken (e.g digging drain)
Define Sustainability [in ecosystem terms…]
- abilty for an ecosystem to mantain biodiversity, while providing humans with resources needed over many generations, without harming the ecosystem over the long-term
Main methods of sustainable SMALL SCALE Timber Harvest
- Coppicing = felling trees close to the ground, leaving behind stump (allowing newer shoots to grow from stump] » allows future harvest of tree + no machines needed….
- Rotational Coppicing = coppicing on rotation, allowing various LIGHT LEVELS to reach ground (biodivserity), and allows tree REPLENISHMENT…
- Pollarding = tree cut 2-3 meters from ground, extending lifespan of tree for long-term » avoids newer shoots eaten by grazers, existing tree roots mantains soil quality
Main methods of sustainable LARGE SCALE Timber Harvest
- Selective Cutting: felling ONLY most valuable trees, leaving immature/non wanted trees alone
- Allowing tree replenishment time
- Trees replanted, and done with large distance between: prevents competition
- Limiting area of felled trees as a whole
Main methods of sustainable LOCAL-WIDE fishing
- Large Net Sizes: ensures only larger, mature fish caught, leaving immature to reproduce and mantain pop.
- Specifies times of year: protecting breeding seasons, allowing pop. to recover
- Fish Farming/Aquaculture: prevents loss of wild species, monitor diseases, controlled exploitation
Main methods of sustainable GOVERNMENT-WIDE fishing
- Surveillance of catches: allowing non-endangered species only to catch
- Banning unssutainable catches: gillnets, bottom-trawling e.g.
- Promoting sustainable fishing practise: e.g. mid-water trawling via Marine Stewardship Council….
