ecosystems test Flashcards
what is symbiosis
relationships between organisms
what is commensalism
where one organism benefits and the other is neither harmed nor benefitted
what is mutualism
when both organisms benefit
what is parasitism
when one organism benefits and the other is harmed
how do ecologists study populations?
by examining their geographic range, growth rate, density and distribution, and age structure
what factors affect population growth
birth rate, death rate, and migration
what happens during exponential growth?
the larger the population gets, the faster it grows
what happens during logistic growth?
The population begins growing exponentially, it slows down, and then the rate of pop. growth reaches 0
_________ demonstrates how genetics and evolution influence each other
population genetics
How many factors change allele frequency within a population?
5
How does sexual selection change the population
Sexual selection changes the population because the traits that attract the most mates are going to show up more often in the Gene pool
Changes in allele frequency due to random chance is…
genetic drift
Changes in allele frequency due to mixing with new genetically different populations
Gene flow
What principle states that under the right circumstances Mendelian genetics works at the scale of a whole population
Hardy-Weinberg Principle
The Hardy-Weinberg equilibrium requires..
No natural selection, no sexual selection, gigantic population size, no mutations, no gene flow
What is the Hardy Weinberg equation?
p^2+2pq+q^2 (q= freq. of recessive allele, p = freq. of dominant allele)
What factors determine carrying capacity?
Limiting factors
What limiting factors depend on population density?
Density dependent factors like competition, stress, parasitism, disease, predation, and herbivory
What limiting factors do not typically depend on population density
Environmental extremes such as hurricanes, droughts, floods, natural disasters, and temperature
What is the relationship between limiting factors and extinction
If limiting factors causes the carrying capacity to fall low enough, populations can become extinct
Intrinsic growth rate is
whether the pop. is increasing or decreasing
A type 1 survivorship curve is most similar to the growth pattern of
K selected species
What is a K selected species?
Species that live long with parental care
What is a r selected species
Species that live shorter without parental care
What are the levels of organization in ecology
Biosphere, ecosystem, community, population, organism
What is the competitive exclusion principle?
A principle stating that no two species can occupy exactly the same niche in exactly the same habitat at exactly the same time
How do keystone species shape communities
If they are removed from an area, it can cause the ecosystem in that area to collapse entirely
What is the Anthropocene
The period during which human activity has become the major cause of global change
What are the steps of Ocean acidification
Carbon dioxide is released from fossil fuels burning, dissolves in seawater, and turns into acid
What kinds of pollutants are drivers of global change?
CFCs (industrially produced gasses), smog, waste, DDT (a pesticide), PCBs (toxic chemicals causing water pollution), and heavy metals
What is the goal of a compost bin
Nutrient rich organic material
Where can carbon be found
Fossil fuels, living organisms, the ocean, atmosphere, rocks
After a long long time, the carbon from the remains of dead organisms can be stored in
fossil fuels
what percent of the air is nitrogen
78%
nitrogen can be fixed by what in the roots of some plants and in the soil
bacteria
What are the key processes of the carbon cycle?
Photosynthesis, cellular respiration, decomposition, fossilization, and combustion
What are the key processes of the nitrogen cycle?
Nitrogen fixation, nitrification, assimilation, ammonification, and denitrification
What is nitrogen fixation?
Bacteria converts nitrogen gas into ammonium ions
What is nitrification
The process of turning ammonium ions into nitrites and nitrates via nitrofying bacteria
What is assimilation
The uptake of nitrate from the soil by the roots of plants
What is ammonification
Decomposers turn nitrogen compounds into ammonium
What is denitrification
The process of turning nitrates into nitrogen gas via denitrifying bactera
The precipitation that hits the ground can run off when
The ground is saturated like a sponge or if it is hard scaped like roads
How do plants get phosphate molecules
Fertilizer and soil
How are layers of new sedimentary rock containing phosphorus formed
The phosphorus compounds in the water and organisms sink to the ocean floor and form the layers
What is Eutrophication
a process by which too much phosphorus runs off into bodies of water
What are the key processes of the water cycle?
Evaporation, transpiration, condensation, precipitation, and percolation
What is percolation?
When water moves through soil layers back to lakes and oceans.
What are the key processes of the phosphorus cycle
Weathering, Surface runoff and fertilizer run off, decomposition, sedimentation, and uplift
What is weathering
The physical and chemical breakdown of rocks
What is sedimentation
Dead marine organisms get compacted by sediment forming sedimentary rocks
What is uplift
A geological process that moves rocks from oceans onto the land
How much energy is passed from one level of a food pyramid to the next?
10%
Why is a food web better than a food chain at representing interactions in an ecosystem?
It is a combination of multiple food chains put together shows the different relationships.
