T14 - Biosphere and ecology Flashcards
What is ecology?
The study of how organisms interact with each other and their environment
Interactions depend on biotic factors (other organisms) and abiotic factors (physical and chemical properties of the environment)
What is organismal ecology?
How organism structure, physiology and behaviours repsond to the environental challenges
What is population ecology?
How biotic and abiotic factors affect population size and how it changes through time
- Population dynamics and growth
Population = group of indivs of the same species living in an area
What is community ecology?
How interactions between species (predation, competition, mutualism) affect community structure and organization
Community = group of populations of different species in an area (these can be microorganisms, plants, animals..)
What is ecosystem ecology?
How energy and chemicals cycle between organisms and the environment
Ecosystem = community of organisms in an area and the physical factors with which those organisms interact
- Takes into factors such as how carbon cycles, humidity levels, resource availability
What is landscape ecology?
What factors control exchanges of energy, material and organisms across multiple ecosystems and how
Lanscape = mosaic of connected ecosystems
- Taking note of effects of things like erosions, volcanic eruptions
What is global ecology? What is another term for this ?
How the regional exchange of energy and materials influenecs the functioning and distribution of organisms across the biosphere
Global ecosystem (biosphere) = sum of all planets ecosystems and landscapes
- Can compare differences in populations on tropic regions vs oceanic regions globally
What is climate? What 4 factors determines this?
Long term weather conditions in a given area
Determined by; temperature, light, wind, precipitation
What is a biome?
A major ecosystem type classified according to the predominant vegetation and the physical environment and characterized by adaptations of organisms to that environment
Where do species occur and why?
Distribution of a species depends on its evolutionary history, biotic factors and abiotic factors
- pace of evolution and how species evolved (specialized)
Where is the highest and lowest diversity found?
Highest diversity in tropics and near shore areas
Lowest diversity near the poles
What is species richness?
Number of species in a biological community
- increase = more speciation (more species have evolved or less extinction has occurs
What are 3 hypotheses that can help explain the gradient in species richness?
- Tropical latitudes receive more solar energy than temperate zones
- more photosynthesis can occur with more sunlight = much longer growing season
- higher productivity
- increase in biodiversity with more resources to accomodate and maintain a wider variety of different species
- Fewer seasonal changes in tropical regions (more stable climate)
- Increase competition leads to a smaller niche (forces them to specialize for one resource)
- leads to an increase in specialization and resource partitioning (fewer species that can exploit the same resource as another = less competition)
- increase in biodiversity
- resources remain stable, there is no need to acclimate to multiple environments/habitats/seasonal changes
- During the ice age, temperate communites were vulnerable to glaciations
- Tropical communities are typically older and have stayed undisturbed for longer
- reduced extinction rates in the tropics
- increase in biodiversity, increase in level in speciation, may have this in temperature regions but they have a higher extinction rate
- glaciation happened near the pole regions, not affecting these tropical regions
What is the net diversification rate?
Speciation - extinction
What is a generalist vs a specialist? What is an example of both?
Generalist = species that thrives in a wide varitey of environmental conditions (different resources)
Ex. raccoons that can eat berries, insects, small animals
Specialist = species that thrives only in a narrow range of environmental conditions (very specific resources)
Ex. Koalas feed almost exlcusively on eucalyptus leaves
What is dispersal?
Movement of indivs away from the area of origin or from centers of high population density
Dispersal might limit its distribution because some may not be accessible or there may not be enough time for a species to adapt to new seasons
There may also be the presence of an invasive species limiting disperal distribution
How can species living along an environmental gradient respond to climate change?
a) Natural range limited to physiological factors (original population might be more climatically suited to one area)
b) Natural range is shifted north = species will colonize new areas
c) shrinkage of natural range because of limited number of habitats avail in the north and south ern limit moving north
d) dispersal barriers prevent colonization of potentially suitable habitats (environmental barriers - mountains - that may block new possible habitats)
e) limited dispersal abilities prevent keeping up with rapidly changing conditions
f) adaptation to new conditions and expansion of the natural range (evolutionary change)
List some examples of species interactions that may influence the composition and dynamics of communities
Mutualism (both benefit)
Commensalism (one benefits, the other is not affected)
Parasitism (one benefits, the other is harmed)
Neutralism (neither are benefitted or harmed)
Amensalism (one is harmed, the other is not affected)
Competition (both species are harmed)
What is the difference between the realized niche and the fundamental niche?
The realized niche is always smaller than the fundamental niche because of competition
- when 2 indivs of different species compete for a resource, limiting their growth and survival
What is competitive exclusion?
When populations of 2 similar species compete for the same limited resource (same prey/occupying the same habitat)
One population will use the resources more efficiently (reprod advantage) leading to the elimination of the other population
Essentially, one species ‘wins’ against the other
What is resource partitioning? What does it accomplish?
The differentiation of ecological niches
Can decrease competition and allow 2 species to coexist
- Different adaptations allow them to exploit different resources
Ex. 7 species of anolis lizards that coexist in the same habitat but occupy different niches (different legs; shorter/longer for catching different prey)
What is bottom up control vs top up control?
The controlling of populations of intermediate trophic levels;
Bottom = amount of food available in lower trophic levels
Top = presence of predators
