Biomes to population Flashcards
What is ecology
the “study of the household [of nature]2
What is a biome
each region with its characteristic climate, day-length, topography, flora and fauna
Community of plants and animals that have common characteristics for the environment they exist in.
Distinct biological communities that have formed in response to shared physical climate.
What 2 abiotic factors are used to classify biomes
precipitation and temperature
Average precipitation of tropical rainforests
60mm - occur in areas where there is no dry season
Where are true rainforests found
between 10degrees N and 10 degrees south of the equator
Where do tropical rainforests usually occur
within the 28° latitudes (between the Tropic of Cancer and the Tropic of Capricorn)
Mean monthly temperature of tropical rainforest
18 degrees C
Average annual rainfall of tropical rainforest
No less than 1680 mm, can exceed 10m. Average - 1750-3000 mm
Why do tropical rainforests have poor soils
due to high level of precipitation
Is biodiversity high or low in tropical rainforests
high - 40 - 75% of all biotic species indigenous to rainforests
Tropical rainforest biodiversity stats
Home to 50% all living animal and plant species on Earth: 66% all flowering plants. 1 ha may contain - 42,000 species of insect, 300 species of trees, 1,500 species of higher plants
Tropical rainforests are being threatened …
due to large scale fragmentation
habitat fragmentation causes
caused by geological processes (volcanism) and climate change in past, identified as drivers of speciation. Human driven fragmentation one of major causes of species extinction
Habitat fragmentation definition
Process by which habitat loss results in division of large, continuous habitats into a greater number of smaller patches of: lower total area, isolated from each other by matrix of dissimilar habitats.
Consequences of patch isolation
reduces population connectivity, probability of population persistence.
Apart from oceans what is the worlds largest biome
boreal forest (taiga)
What is the % cover of boreal forest
29% of world’s forest cover
Where is boreal forest found
throughout the high northern latitudes, between tundra and temperate forest, about 50° N to 70° N.
How is boreal forest charcterized
by coniferous forests: mostly pines, spruces and larches
After tundra/permanent ice caps which biome has lowest annual av temperature
boreal forest
Boreal forest climate
sub-Arctic climate with very large temperature range between seasons; long and cold winter is dominant feature.
Boreal forest summers
1-3 months (always less than 4)
How long do winters last in boreal forest
5-8 months
How much does temperature vary in boreal forests
-54 to 30 degrees C
Typical winter day temperature - boreal forest
-20 degrees C
Typical summer day temperature - boreal forest
18 degrees C
Boreal forests type 1 - southern: closed canopy forest
many closely spaced trees with mossy ground cover
clearings with shrubs and wildflowers common.
Boreal forest type 2 - Northern: lichen woodland or sparse taiga
trees more spaced and lichen ground cover
forest cover often stunted in growth form
in North America ice-pruned and asymmetric with diminished foliage on the windward side
Where are temperature deciduous forests found
areas with moist summers and mild winters.
Three major areas occur in Northern Hemisphere: North America (mainly Eastern), East Asia, Europe
Smaller areas in: Australasia, North America (Western), Southern South America
What are temperature deciduous forests dominated by
trees that lose their leaves each year
Typical trees found in temperature deciduous forests
oak, maple, beech and elm (Northern) and southern beech, Northofagus spp. (Southern).
Where is diversity higher in temperature deciduous forests
where winter milder and mountainous regions that provide array of soil types.
Where is the largest intact deciduous forest
6 million acre Adirondack Park, upstate New York
How did human colonization effect temperature deciduous forests
Harvested wood for timber and charcoal. Many forests small fragments dissected by fields and roads. Introduction of exotic diseases a threat to forest trees (e.g. chestnut and elm). Animals such as deer (clearing rather than forest animals), expanded range and proliferated
Describe a desert
Barren area of landscape where little precipitation occurs.
Annual precipitation in a desert
25-200 mm - some years none
Biodiversity in a desert
low - Living conditions hostile for plant and animal life. Lack of vegetation exposes ground to denudation.
what % of land surface is arid or semi-arid (little rain)
33%
What is a desert classified by
precipitation, temperature, causes of desertification, geographical location.
What are the 3 types of desert climate
Hot – between 30 ° S and 30 ° N (horse latitudes).
Mild - west coasts of continents; near-tropical locations.
Cold - typically located in temperate zones. (Arctic and Antarctic regions have polar climates).
Beetle in the desert
Stenocara gracilipes, beetle native to Namib Desert, Southern Africa.
Very arid area: 1.4 cm rain per year.
Beetle survives by collecting water on rough back surface from early morning fogs and humid air
What renewable energy source are deserts good for
renewable energy source - Mojave Desert (USA) Solar Park – large areas covered in mirrors; combined capacity 354 MW.
Sahara Desert – estimated all of the world’s electricity needs could be supplied from from 10% of Sahara. Major European interest – DESERTEC.
Negev Desert, Israel
What do anthromes include
Urban, Village, Cropland, Rangeland, Seminatural anthrome
What are anthromes
Globally significant ecological patterns created by sustained interactions between humans and biomes / ecosystems.
Define ecosystem
Whole community of living organisms in conjunction with the non-living components of their environment (e.g. air, water and mineral soil).
What do ecosystems usually include
Primary producers, Decomposers and detritivores, Pool of dead organic matter, Herbivores, carnivores and parasites, Physico-chemical environment (source and sink for energy and matter)
How are biotic and abiotic factors linked together in an ecosystem
through nutrient cycles and energy flows
What is respiration
plants (animals and micro-organisms) release carbon locked in photosynthetic products back to atmospheric and hydrospheric carbon compartments
What is primary productivity
rate biomass produced per unit area by plants, the primary producers
What is gross primary productivity
total fixation of energy by photosynthesis
What is autotrophic respiration
proportion energy fixed by photosynthesis lost by respiration
What is net primary productivity
difference between GPP and RA; represents actual rate of production of new biomass available for consumption by heterotrophic organisms (bacteria, fungi and animals).
What is secondary productivity
rate production of biomass by heterotrophs
Different types of patterns in primary productivity
1.Latitudinal trends in productivity
2.Seasonal / annual trends in primary productivity
3.Autochthonous and allochthonous
4.Variations in productivity to biomass relationship
5.Above-ground NPP and below-ground NPP for five categories of grassland ecosystems
What is autochthonous
Organic matter produced by photosynthesis within an ecosystem’s boundaries
What is allochtonous
Organic matter imported from elsewhere
Consumption efficiency formula
energy consumed (C) / Energy availabke (T)
Assimilation efficiency formula
energy assimilated (A) / energy consumed (C)
Growth (production) efficiency formula
energy fixed in tissues (P) / energy assimilated (A)
Who has higher assimilation efficiencies
organisms further along the food chain because of their diet quality
Why is diet quality improved as you go further along the food chain
Herbivores have plentiful supply: 33% may be non-digestible cellulose (without bacteria) Assimilation efficiencies low – around 10%. Need to consume large volume of vegetation
Carnivores: energy as fats and proteins. Richer and more readily digestible. Assimilation efficiencies as high as 90%
What are endotherms
warm blooded animals
Endotherms metabolic costs
high metabolic costs; over 90% of energy income may be spent in maintaining body temperature
What are ectotherms
cold blooded animals
Ectotherms metabolic costs
rely on external heat sources; can devote more of their energy to production
What is production efficiency
percentage of assimilated energy incorporated into new biomass
Define communities
A naturally occurring group of plants, animals and other organisms interacting in a unique habitat.
What do communities add to their habitat
The complex range of interactions between the component species provides an important level of biological diversity in addition to genetics and species
How can we understand communities
by examining the two-way, and then the multi-way, interactions involving pairs of species or many species
Define mutualism
the way two organisms of different species exist in a relationship in which each individual benefits from the activity of the other.
What is co-operation
mutualism within a species
Mutualistic protector example: striped cleaner wrasse Labroides dimidiatus
Establishes “cleaning station“ (cave or overhang); swims in a bobbing, dance - like motion. Larger fish come to the cleaning station for ectoparasite removal. (client clean - less infection)
Swims around the fish picking off and eating the parasites. Often enters the mouth and gill chamber of large fish (food source)
Farming mutualisms - leaf-cutting ants
Fungus only grows in the underground chambers of the ants’ nest
Ants actively cultivate their fungus (Lepiotaceae family) and maintain it free from pests and moulds
bacterium that grows on the ants secretes chemicals which protect the fungus from moulds - portable antimicrobials.
When ants bring back toxic leaves, fungus secretes a chemical that warns the ant not to collect any more of that type of leaf
Pollination mutualisms
Nectar and pollen offered as reward
Reduces wastage of pollen
Costs: pollinator attraction, disease transfer
Pollinators par excellence – insect
Which animals have a rumen
cows, sheep, goats and cammels
Function of the rumen
Microbial populations collaborate to digest cellulose and other polysaccharides producing carbon dioxide, methane and organic acids.
Microbial content in the rumen
Fungi (digest lignin and cellulose), Bacteria, Protozoa- mutualistic relationship to live in the rumen
How big is the rumen in sheep and in cows
In sheep, ~ 6 L; in cows, ~ 50-150L
What is interspecific competition
Individuals of one species suffer a reduction in fecundity, growth or survivorship as a result of resource exploitation or interference by individuals of another species
Interspecific competition: Dolly Varden Charr
Either species alone, higher temperature led to increased aggression
Effect reversed when Dolly Varden charr in presence of white- spotted charr
At higher temperatures Dolly Varden charr suppressed from obtaining favorable foraging positions when white-spotted charr present
Dolly Varden charr also suffered lower growth rates
Interspecific competition example: Galium hercynicum and G.pumilum
Galium hercynicum grows naturally in UK at acidic sites; G. pumilum confined to more calcareous soils.
Alone – both species thrive on both soils
Together – only G. hercynicum grew successfully on acidic soil and only G. pumilum on calcareous soil
Together species compete; one species competitively excluded. Outcome is habitat – dependent
Interspecific competition example: paramecium aurelia, P.caudatum, P.bursaria.
Laboratory experiment. Paramecium consumed bacteria or yeast cells; these lived on regularly replenished oatmeal. All three species grew well alone, reaching stable carrying capacities in tubes of liquid medium
P.aurelia and P.caudatum together. P. caudatum always declined to the point of extinction, leaving P.aurelia as victor
P. caudatum and P.busaria together. Neither species suffered a decline to point of extinction. Stable densities much lower than when grown alone – indicating competition
What is Gause’s principle: competitive exclusion principle
If two competing species coexist in a stable environment, then they do so as a result of niche differentiation, i.e. differentiation of their realized niches.
If, however, there is no such differentiation, or if it is precluded by the habitat, then one competing species will eliminate or exclude the other
What is a population
A group of organisms of one species. Usually separated in some degree from other groups of the same species by geographical, topographical or by some boundary chosen by investigator
When does random spatial distribution occur
variance = mean
When does contagious spatial distribution occur
variance greater than mean
When does regular spatial distribution occur
variance is less than mean
Which spatial distribution is the most common and why
clumping - because there is safety in numbers and there is social interaction to care for young and help to access resources. Resources are clumped
Why is uniform distribution
used because of scarce resources - not as cpmmon
Why is random distribution hard to determine
hard to say if it is truly random or largely clumpy - quite rare
How do population exhibit dynamic behaviour
through the action of changing rates of emigration, immigration, birth and death. It is the quantification and explanation of these numerical changes that concern the population ecologist
What is exponential growth
when uncrowded populations grow by simple multiplication over successive intervals of time
What happens to populations that have continuous exponential growth
they run out of resources - Competing individuals that fail to find resources they need may grow more slowly or even die; survivors may reproduce later and less; or, if they are mobile, they move further apart or migrate elsewhere
What is carrying capacity
A species’ average population size in a particular habitat
What shape is the population rate when it gets closer to K (carrying capacity)
there is a reduction in the rate of increase giving S-shaped curve. Logistic grow pattern
Relationship between population density and rate of increase - what is this referred to as
inverse relationship - density dependent effect
What are the 2 extreme forms of intraspecific competition
contest competition and scramble competition
What is scramble competition
Resource is shared amongst all the competing animals
Sharing would be equal and the mortality would raise immediately from 0 to 100% when the resource per capita becomes just insufficient for survival
What is contest competition
Each successful animal gets all it requires.
The unsuccessful animals get insufficient for survival and reproduction.
Mortality increases with density
Example of contest competition
Competition between solitary wasps for limited number of nest holes
r-selected species
Potential to multiply rapidly - producing large numbers of progeny early in the life cycle.
Strategy advantageous in environments that are short-lived.
Allows organisms to colonise new habitats quickly and exploit new resources.
Spend most of their life in the exponential, r-dominated part of population growth
Example of r-selected species
Annual weeds (invade disturbed land), mosquito larvae (temporary puddle), blowfly laying their eggs on a dead chick
K-selected species
Organisms with different life histories survive in habitats where there is intense competition for limited resources.
Successful individuals are those that capture, and often hold on to, the larger share of resources.
Those that win in struggle for existence do so because they have grown faster (rather than reproducing) or some other activity (e.g. aggression) has favored them.
K-selected species example
whooping crane, redwood forests, mike whale
