Weeks 11-12 Flashcards
what defines a community
all species that occupy the same habitat at the same time
what defines an ecosystem
the organisms + the abiotic factors
what is the most important reason as to why species are found in some areas an not others
dispersial - if it cant go there it cant grow there
what are the ecological filters
-dispersal - disperse to certain area
-environmental (abiotic) - is the species able to grow in the environment
-interaction (biotic) - will species survive interactions with other organisms
why isnt speciation important for determining species diversity on a local scale
it happens over a much larger area so it wont work on a local scale
how do species co-exist in a community
they occupy diff niches/have diff roles (resource partitioning/niche differentiation)
TF a species niche can be defined by both abiotic and biotic factors
T ex) temp it thrives in, food it eats, space it occupies
how are niches affected by other species
the niche can either increase or decrease based on the type of interaction
what is a fundamental niche
the space and resources a species uses when not interaction with other species (the maximum range)
2 species w similar niches will
slightly shift away from eachother for less competition
TF 2 species with a very similar niche will coexist and fight for it
F, if the niche is too similar - they are not likely to coexist
what can help the number of species living in an area besides resource partitioning
moderate natural disturbances (help species to not out compete one another)
- fire
- grazing
- predation
- flooding
what is a keystone species
A species that has a large effect on an ecosystem e.g. maintains biodiversity and balance, but that is NOT the dominant species
what is it called when 2 species benefit from eachother
mutualism
what is it called when one species benefits while the other is being harmed
parasitism
what is it called when 2 species only do harm to eachother
Competition
what factors determine biodiversity at the local scale
disturbances
immigration
diversity and resources
available niches
what defines a mass extinction
over 75% of species gone within 2 mil yrs
what are some factors that could have led to mass extinctions
volcanic eruption
ocean acidification
asteroid impacts
increased Oxygen
what happened in the first extinction (ordovician-sulurion)
ordovician-sulurion extinction
- wiped out many marine invertebrates
- benefitted early vertebrates
what happened in the 2nd extinction(devonian)
devonian extinction
- wiped out many ancient fish species
- benefitted early land vertebrates and seed plants
what happened in the 3rd extinction (permian-triassic)
permian-triassic extincion
- wiped out many marine vertebrates, amphibians, and proto mammals
- benefitted dinosaurs
what happened in the 4th extinction(cretaceous-paleogene)
cretaceous-paleogene extinction
- wiped out all non-avian dinos
- benefitted small mammals, birds, flowering plants
what are the biggest world threats to biodiversity
changes in land and sea use
species overexploitation
invasive species and disease
pollution
climate change
what type of human activities lead to habitat fragmentation/ degradation/ loss
- intense agriculture (urban areas)
- resource extraction (logginh/mining)
which factors determine how fragmentation affect wildlife
species
size and shape of fragments
number of fragments
distance between fragments
characteristics of the matrix
connectivity of fragments
whats the difference between habitat: loss - fragmentation and degradation
loss = cannot support population
degradation = cant support lrg populations
fragmentation = might support populations
TF for some species, habitat fragmentation = habitat loss
T
TF priority species are less affected by fragmentation
F, more affected
how else does fragmentation affect species
some species need to travel long distances for food/ mate and can get blocked by a highway or river etc
what is the edge effect of a fragmented habitat
When a large habitat is fragmented (broken into smaller pieces), the amount of edge area increases compared to the interior
- the edge environment is different from the interior (core), more edges = less safe space for the species that want the deep undisturbed habitat
TF more edge effect = more core habitat
F, less core habitat
what are some abiotic factors of the edge effect
more sun
more light
dryer soil
more wind
inc temp
what are some biotic factors of edge effects
altered species
altered plant dispersial
increased invasive plants
more competiton/predation
why cant habitat fragmentations support high biodiversity or lrg populations
Not enough niches or resources
what is the extinction vortex
the cumulative effect of many different factors
leads to a smaller and smaller population.
TF some keystone species are the top predators
T
what are ecosystem engineers
a type of keystone species that physically modify, create, or maintain habitats, shaping the environment in ways that benefit many other organisms
what is an invasive species
- species that disrupts an ecosystem
- they displace or prey excessivly
- grow/spread quickly
what makes an introduced species invasive
quickly reproduce
dont have natural predator
exploit/overtake open niche
what are 3 types of keystone species
Predators
ecosystem engineers
mutualists
what is a mutualist keystone species
form important relationships, pollinators
what is the #1 most likely consequence of climate change
species shifting (moving locations)
- have more predators, more comp, and more niche issues
ecosystem stability comes from what 2 components
- resistance (ability to remain enchanged)
- resilience (ability to recover from disturbance)
what are foundation species (alongside keystone species)
build up the structure of an ecosystem
and provide habitats
Why is a diverse community/ecosystem more productive ?
-Can effectively utilize many different resources (less
competition)
* Are more resistant to disturbances
* Recovers quicker from disturbances
* Can consistently produce high amounts of biomass
over time.
