Lecture 1 -- Ecology Flashcards
basic definition of ecology
science of how organisms interact with one another and their environment
what two componenets does ecology include
abiotic and bitotic
abiotic
non-living things like environment, nutrient cycles, soils, temperature
biotic
all living organisms
modern ecology vs natural history/ecology
in modern ecology, we use approaches that involve technoliogy, which help attain data, and pictures, we also use experiments and natural observations. The technology and experiments are what differ from natural history/ecology.
what do ecologist often examine
distribution and abundance.
distribution: they examine the limits, and how distribution is changing.
Abundance: they examine changes in the abundance, and if populations are growing or shrinking
the importance of ecology in YOUR world
climate change, mass extinction, biodiversity loss
types of problems addressed by ecology.
- conservation and biodiversity
- environmental issues
- wildlife and resource management
- pest control
- human health
conservation and biodiversity `
evaluate effectiveness of conservation strategies (do marine protected areas work)
environmental issues
evaluate consequences of human activities (pollution, fishing, hunting) (what effect is climate change having on biodiversity)
wildlife and resource management
evaluate effectiveness of management strategies (when does fishing become overfishing) for humans this is a loss of job because lack of fish and for fish this could mean extinction
pest control
strategies for reducing crop losses
human health
how diseases spread through animals (lyme disease)
levels of ecological study
organism, population, community, ecosystem, landscape/seascape, global
organismal ecology
how organisms adapt to environment, maybe look at the genetics
population ecologyu
looking at how same species interact w each other.
community ecology
multiple species interacting; multiple population
ecosystem ecology
both organisms and abiotic environemnt.
landscape/seascape ecology
connected ecosystems, for example how organisms ca move between ecosystems via lakes..
global ecology
the biosphere, all life on earth.
limits to distribution: concept
concept of biomes. why there are no trees in the far north (tundra)
terrestrial biomes
major ecosystem type, classified by dominant vegetation. it starts near the poles and makes way to equator.
tundra
terrestrial biomes.
far north, ~60º N, expansive area of ARCTIC. it is treeless, because the ground is permanently frozen. therefore there is no nutrients for the roots. ON SCALE (cold and dry)
northern coniferous forest.
examples include Canada and Russia. latitude is ~50-60º N. it is evergreen, needles. these evergreens are retained all year round because the leaves (needles) are energetically worth it and prevent the loss of water. strong seasonal signals (cold long winters, warm short summers)
ON SCALE they are in the middle, near more cold weather
temperate broadleaf forest
broad leaves, deciduous which means they drop their leaves in the fall because they are not energetically worth it. in the summer the leaves grow again, these leaves change colour,. around latitude of 30º N.
ON SCALE they are just above coniferous as they differ slightly in seasonal changes.
tropical froest
evergreen, broadleaves, these leaves photosynthesize all year round, therefore they are energetically worth it. hot and humid. ON SCALE at the very top right, high in temperature, and very wet. EQUATOR
distribution is correlated with latitude
the hypothesis is that the climate drives the observed biome patterns.
what are some tradeoffs for the hypothesis of terrestrial distribution
energy, adaptations, vegetation cannot dominate, no organism is perfectly adapted to environment.
Savanna
grass land with very few, scattered trees. Difference seasonally compared to tropical rainforest. its precipation has dry/wet seasons, but tropical is always wet. Its temperaturte is always hot just like tropical. this is near EQUATOR.
disturbance
an event that reomves individuals from a population – stops ecosystem from reaching equilib rium
why is there only grass in savannas
deisturbances such as large herbivore grazers that graze the trees which limits them from growing, and fires. Grass can grow more rapidly which is why it is domiant over trees.
temperate grasslands
grasslands, differ in precipitaton, compated to temperate broadleaf. the grassland is much drier than the broadleaf but the temperature is the same for both (cold/warm). latitude is around 30º N
changing distributions; what limits distributions
dispersal, abiotic factors, biotic factors.
dispersal; limiting distribution
organisms didnt / cant get there. an example is islands. Islands’s biodiversity id very unique because it id isolated so organisms have a hard time entering or leaving.
abiotic factors; limiting distribution
enviornment - temperatutre, moisture, salinity (ocean), oxygen (ocean) – if an organism is not adapted to the specific environment it cannot thrive and persist
biotic factors; limiting distribution
resources (food), competition, predation, disease.
coyote example ; why did coyote distributiuon change?
- the wolf distribution changed. the wolves moved out of the south into the north, which lead to wolf extermination where coyotes were still present. This extermination decreased the biotic interaction between the coyote and grey wolf (predation on coyote by wolf). therefpre more coyotes survived.
- european settlement. The agriculture led to forest removeal, which is why wolves moved. this means there was an abundant amount of rodents and other small prey for the wolves, as the habitat started to resemble grassland. this conversion enabled the coyote expansion`
what is a population
a group of individuals of a single species living in the same area.
interspecific interaction
interactions between different speciesi
intraspecific interactions
`interactions within the same species
potential to interact examples
mating, socialize, compete for food.
population dynamics
when population changes – abundance and density can change overtime.
popuylation size
number of individuals
density
number of individuals per unit area.
Desert
latitude is 30º N and S, it can be hot or cold. it is defined by dry, low precipitation. organisms should be able to tolerate hot and dry conditionds and be able to deal well with sudden heavy rainfalls.
why are deserts at 30º latitude (explain using sunlight direction)
sun light directly hits the equator. The warm, moist air rises, and releases moisture via rain. in doing so, it will dry the air out, and will get pushed away from the equator (30º latitude). The dry air will absorb moisture, contributing to the dry conditions at the latitude before being recirculated. This circulated process is the Hadley cells.
Desert locusts life cycle, and nutrition and problems they bring
they are herbivores, and eat their own weight in plants each day.
they have a life span of about 4 months.
- egg (100 / female)
- juvenile (hopper)
- adult
a problem that comes from a large number of locust is food security for humans because they can clean out vegetation in an area.
outbreaks definition
a rapid increase in the population abundance, – something allowed the population to grow rapidly.
exponential growth model
dN/dt = rN
where dN/dt is the rate of change in population over time.
r = per capita growth rate
N = popluation size.
how r contributes to population
when r = + then population increases
when r = - then population decreases
when r = 0 population is constant, doesnt change.
larger r = faaster growth
smaller r = slower growth
exponential growth
unlimited growth; unlimited resources/environment/
what is per capita growth rate determined by
birth rate b, death rate d, immigration rate i, andn emmigration rate e. r = b+d+i-e
closed population
example is islands, individuals are isolated, therefore closed population – no immigration or emmigration (r=b-d)
open population
per capita population growth (r) depends on m (i-e), b, and d. r=b-d+m
what causes a desert locust outbreak
has to do wit birth rates increasing. the bir rates depend on the environment, because resource availability will increases therefore more eggs are able to survive. The desert has very low, variable rainfall, so when it does rain it is very intense. The heavy rainfall leads to new vegetation which is new energy source for the female locusts. But whats so special about locusts? this is truwe for many animals. because of the new vegetation and increased birth rates, the locusts will start to clump, this is just individual locusts clumped together in groups for various reasons like social, mating, and defence against predators. then they crowd. and the last step that is unique is gregarization which is a change in behaviour from solitary to social creatures that aggregate together.
what happens when the locusts are gregarized
because they are so close, the hairs on their arms and legs will brush against one anothewr and this stimulates hormones to be released (serotonin)
low density vs high density
low = solitary, pale green, fly alone at night
high = gregarious, strong colours, fly in swarms during the day
how does the outbreak end
the rain ends therefore no more new vegetation, the locust will eat everything, and they will revert back to solitary form because it is no longer crowded.
