Ecology! Flashcards
what is ecology?
- science of how organisms interact with each other and their environment
- abiotic and biotic components
- must ensure ecosystems are sustainable
What is modern ecology?
- uses approaches such as observational, experimental, data analytical, stats modelling, community engagement and verse knowledge systems
What two factors do ecologists examine?
Distribution and abundance
What is distribution?
- limits to distribution and changing distribution
What is measured in abundance?
- changes in abundance, are populations growing or shrinking
What types of problems are addressed by ecology? (5)
- Conservation and biodiversity - effectiveness of conservations strategies
- environmental issues - evaluate consequences of human activity
- wildlife and resource management : when does fishing become overfishing
- Pest control: strategies for reducing crop loss (without harming environment )
- Human health: How are diseases spread through animals ?
What is the organism level of ecological study?
- how organisms adapt to environment
What is a population?
Same species
Community?
Multiple species
What is ecosystem?
- organisms and abiotic environment
What is landscape/seascape?
- connected ecosystems
What is global ecology?
Considers the biosphere
What is the most significant influence on distribution of organisms?
Climate
What is the climate?
- long term prevailing weather condition in a given area
- includes temperature, precipitation, sunlight, wind, seasonal patterns
What determines the climate?
- input of solar radiation
- earth’s movement in space
- large bodies of water
- mountain ranges
- greenhouse gases
What are the main climate determinant?
solar radiation and earth’s movement In space
What are climate modifiers?
- large bodies of water, mountain ranges, greenhouse gases
How does solar radiation impact precipitation and evaporation?
Heat from direct sunlight at equator drives evaporation, rising moist air cools and releases moisture as precipitation
Describe the evaporation cycle
- rising air cools and release precipitation, depending air then absorbs moisture leading to arid climates
Why is there seasonal variation as a result of sunlight?
- summer north hemisphere pointed towards sun
- winter north hemisphere pointed away from sun
describe how air behaves on a mountain range
- cool, most water form offshore. Air warms as it crosses land.
- Air flowing over mountain cools and releases moisture as precipitation
- Dry air picks up moisture
Would there be more plant diversity before or after a mountain range?
Before, because it hasn’t yet lost its moisture and is not taking moisture from the ground, allowing for more plant life
What are the characteristics of northern coniferous forests ?
- largest terrestrial biome on earth
- winter cold, summer hot
- dominated by cone bearing trees like spruce, pine, hemlock
Describe the temperature precipitation chart for biomes
tundra, north coniferous forest, temperate broad leaf forest, tropical forests
(increasing linearly on a chart of temperature and precipitation)
What are biomes ?
Major zones of life name for climactic features and predominant vegetation
What is disturbance?
- event which removes individuals from a population
What are the two forms of disturbance? What are their impacts ?
1) large herbivore grazers
2) fire
Without fire and grazing, savannah would be woodland. instead trees and grass removed, grass grows back faster
Describe the biomes on a chart of precipitation and disturbance
tropical savannah: high disturbance, low precipitation (dry)
tropical forest : low disturbance high precipitation
will changing climate alter biomes?
as temperatures rise biomes and ecosystems are shifting towards poles
What is one example of the climate altering biomes ?
- edge of boreal forest moving north and up mountain slopes (for cooler air in order to grow)
What are some impact on species?
Range shifts, impacts on people, distribution changes
What are range shifts ?
- species redistribute to stay within climate
- leads to movement away from equator and towards poles
- deeper in oceans
- pests may be more common in warmer climate
What are the reasons some species may not be able to shift to suitable temperatures ?
1) suitable habitat not available
2) some species may not migrate quickly enough to track suitable climate
What are some impacts on people of a changing climate?
- increased vulnerability: food, water, health, habitat. infrastructure impacted
- trend shows nations impacting climate greatest are least affected by climate change
what are some human causes for distribution ?
- habitat destruction, climate change, pollution, overexploitation, invasive species
What limits distribution?
dispersal: organism couldn’t ge there
Abiotic factors: temperature, moisture, salinity, oxygen
biotic factors: resources, predation, competition, disease
In coyotes in the northern hemisphere, what are some reasons for their distribution?
- wolf disruption changed (less competition and wolf hunting makes easier expansion for coyotes)
- European settlement : agriculture leads to forest removal, habitat resembles grassland, small prey, enables coyote expansion
ie: can conclude biotic factors are the cause of this distribution
What are some primary causes of climate changes?
- co2 and other greenhouse gases (methane) trapped in earth’s atmosphere
What is a population?
A group of individuals of the same species living in the same area
How can population ecology be used?
Measuring population size, population growth, life history, and diversity
What are the 2 ways of measuring population size?
1) census: direct measurement of population
2) indirect indicators
Why is a census impractical?
Not all species can be easily counted (too small, too many)
Why are indirect indicators effective?
- can be applied to small/many species
- less resources, less time, less costly
What are some examples of indirect indicators?
of nests, burrow, tracks
- CPUE : catch per unit effort
- mark recapture methods
What is a catch per unit effort?
- can demonstrate how many ish are caught per 100 hooks, represents whether populations are declining
- in class graph shows that overexploitation is occurring
What is the process of mark capturing techniques in mobile animals?
initial sample caught, later remeasured to see how many are in second sample to determine population growth
S = initial
N= number in 2nd sample
x= total number of individuals previously marked in 2nd sample
N (population size) = (s x n) / x
What are the assumptions of the mark recapture technique?
- no individuals born, die, immigrate, emigrate
- marked and unmarked have same probability of being caught
- marked individuals mixed completely back into population
What does a large r mean on an exponential growth model means?
faster growth
What is an exponential growth model?
Describes population growth in an idealized, unlimited environment
What causes a population growth rate to slow?
- resources limited, food and space limited, competition
What are the 2 kinds of competition?
Intraspecific and interspecific
What are some limits to population growth?
- resources become less abundant
- birth rate decline of death rates increase
Is birth rate density dependent or independent in sea otters?
density independant
Is death rate density dependant or independent in sea otters?
Pup death rate is density dependant (thin mothers, pups die)
What is a carrying capacity?
- the number of individuals of a population that an environment can support
- density dependant regulation
Are death rates always density dependant like in otter pups?
NO, it depends on the species
ie: dune grass death rate independent of density, birth rate declines due to water and nutrients being limited
What is the logistic growth model?
Has a carrying capacity
- N (population) = K (carrying capacity)
What does small N, high K mean for r?
large r
What does large N, small k mean for r?
Low r
What are some oversights with the logistic growth model in applying it?
- doesn’t account for influence on other populations,
- carrying capacity is not necessarily static,
- how environment changes
What is the term for when a population is regulated by a food source?
Bottom up
What is the term for when a population is regulated by predators?
top down
What is life history?
traits that affect and organisms schedule of reproduction and survival
What are the 3 variable of life history?
- age of first reproduction
- how often reproduces
- how many offspring
What are R strategists?
- maximize # of offspring, no parental care, smaller offspring,
- disturbed / open, temporary, unpredictable habitats
- invading species
- strength in numbers: can survive harsh and unpredictable environments
What are K strategists?
- maximize offspring survival, larget, parental care
- permanent crowded habitats
- strong competitors, number increase over time
Describe the survivorship curve
-K: low death rate, many live to old age
R: high death rate, many die young
Are all organisms K or R strategists?
No
What is population diversity?
- there are 220 distinct populations per species
What are the forms of species interactions?
Competition, mutualism, commensalism, parasitism, predation, and herbivory
Describe competition
- individuals of 2 species competing for resources required for growth and survival
- both species do better without the other
What is competitive exclusion?
One will eventually outcompete the other
What are interspecific competitors?
- use the same resource, resource is limited
what was the 1st experiment performed with the barnacles?
experiment 1: balunus removed, chthamalus settles and remains
- balanus present, chtamalus nearly gone
Conclusion: Balanus excludes chtamalus from the lower shore (interspecific)
What was the 2nd experiment performed with the barnacles?
- chthamalus present, balanus moves in, balanus dies
- chthamalus not present, balanus moves in, still dies
Conclusion: Chtamalus does not exclude balanus, not suited for environment
What is an ecological niche?
The position of a species within an ecosystem
- conditions necessary for its survival, the role played in an ecosystem
What are the 2 forms of ecological niches? What do they do?
- realized niche: the ‘observed’ niche that it occupies in the wild
- fundamental niche: the conditions in which it can survive and reproduce
What is the niche of the balanus?
realized = fundamental (resides where it can survives)
What is the niche of the chtamalus?
Realized < fundamental (infraspecific competitions makes it such that the niche it naturally inhabits is not viable)
What is the competitive exclusion principle?
- if two species compete for one resource, the better competitor will eliminate the other
- species must occupy somewhat different niches
Can two species with the same niche exist?
cannot coexist
What is resource partitioning?
- two species can coexist if one or more significant differences in their niches are present,
- May arise from character displacement
What is character displacement?
- evolution of differences in morphology and resource use as a result of competition