Bio2129 lecture 3
Ecology seeks to
undertsnd the general processes and laws that govern the distrobution of species and their interactions within the physical enviroment
what must we understand when it comes to ecology
the naural history
what is natural history in the ecology
observation of organisms behaving and interacting with their surroundings, this includes other organisms and their enviroment.
what are some important ecological characteristics
Biomass, ecosystem functions/services, species diversity, population and species distrobution
what is biomass
the mass of living materials in a defined area. can be living or dead and include species, area and biological communities
biomass can be a ...
natural phenomenon or caused by human activites (ex. stream pollution)
what happens when biomass is negtaivley affected by human activities (stream polluted by sewage)
1)Biodiversity loss: excess algae block sunlight which other submerged plants need to survive. 2) Trophic level distrobution : algae dominates the food web and the system of trophic levels are no longer balanced. when alegae die, consumes O in ecosystem. 3) Water quality: algae produces dead zones, making water harmful to humans. 4) Ecosystem transformation: changes in biomass effect how nutrients and gases cycle.
shifting trends in biomass =
biogeochemical and climate changes
what are ecosystem functions
the biophysical interactions in an ecosystem that keep it running. the fundemental biological, geochemical and physical processes.
What is primary productivity
The rate at which autotrophs ( like plants, algae, phytoplanton) produce new organic matter (biomass) through photosynthesis
How do primary producers function
autotroph absorb CO2 from the atm and convert it into organic matter (glucose and plant tissues) using sunlight
what are the roles of primary productivity
base of all food webs (everything depends on the engery captured by autotrophs), regulates carbon balance by absorbing CO2, determines how much energy is available for other trophic levels.
Why is primary productivity important
high primary productivity produces fertile soil and more food production. influences biodiversity
more productivy = more herbivores because..
ecosystems with a higher biomass can support a bigger population of grazers
how can Herbivores also affect productivity
grazing lowers biomass, but makes way for new growth by preventing build up of old or deat plant material.
Productivity varies by
location, some regions produce more plant biomass then others
why is water cycling an important ecosystem function
is controls how nutrients move through ecosystems, heavy water loss (erosion) can wash away nutrients and reduce soil fertility
what are some more examples of ecosystem functions and services
Decomposition ( breakdown of dead organisms and recyles them back into soil, which supports primary production) Biogeochemical cycles ( cleans water, nutrient rich soil, stable climate) Pollination ( plants reproduce via pollen and allow crops to grow)
why is species diversity good
effects how ecosystems function, which can also have an effect on functions that humans need to survive.
losing species diversity can...
reduce productivity, make ecosystems less stable because of drought, fire or climate change.
why is species abundance important
population estimates help to dtermine whether a species is considered threatened or endangered (legal protection)
what is hyperabundance
when species becomes very abundant, it can alter the biotic environment and ecosystem balance
what is species distrobution
where species occurs geographically. its range
why is species distrobution important
helps use describe and predict where species are found now and where they might be spread in the future. important for conservatio, species management and predicting impact of climate or land-use change
what is primary succession
the process where life colonizes an area that was previously sterile and had no living organisms or soil. overtime species like (lichen, mosses or certain plants) slowly build up soild and organic matter that makes it possible for other species to grow.
how does species abundance affect human economies
abundant and accessible populations can provide economic value, but sustainability is threatened by environmental change, overharvesting and ecological interactions
what are the factors that influence ecological characteristics
History, evolution, Physiological tolerance, Limiting resources and
Biotic interactions
how does does evolution affect species distrobution
shaped by evolutionary history and barriers to dispersal
what is wallace's line
a deep-water barrier in southeast asia separates regoins with marsupials from from placental mammals
Evolution usually opertates
over long timescales, which means slow changes in ecological timescals
what organisms is an eceptions to the time scales of evolution, why?
bacteria because they can reproduce so quickly that evolutionary changesare observable in a short time frame
what is an niche
the totale set of environmental conditions a species can tolerate ( temperature, light, subtrate, water)
what is the defintion of an ecological niche
an n-dimentional hypervolume that defines where a species can persist.
what is the key point of ecological niches
organisms usually need multipule enviromental conditions simultaneously not just one factor
what is physiological tolerance
the range of environmental conditions (like temperature, moisture, salinity, pH, or light) that an organism can survive, grow, and reproduce in.
rapid environmental changes can
pass the tolerance and cause mortality
physiological tolerance influences
a species geographical range
why is physiological tolerance important
it is critical for adaptation and distrobution of life on earth
what challenges are there in physiological tolerance
rapid change in environment can exceed tolerance and caus emortality
what are limiting factors
a factor essential for individual growth that can become depleted and limit further growth or survival
example of limiting factors
nutrients like (N,P,K), light, water, space
what is th elaw of minumum
growth is controlled by the scarcest resource, not the total resources available
what are biotic interactions
interactions among living organisms that influence nuches and survival
what are the types of biotic interactions
competition, mutualism, parasitism, predation
distrobution is not just tolerance but shaped by
biotic interactions
fundamental niche
all conditions a species could occupy without competition
what is a realized niche
actual competition a species occupies after competition
what is Liebig’s Law of the Minimum
Whichever essential factor is in the smallest amount relative to an organism’s needs will limit its growth