2nd Bio Midterm

2200 - Lectures 14-21

what can structure biotic factors

• abiotic factors

niche definition

• the specific range of resources a species uses

fundamental niche definition

• theoretical range of conditions a species can tolerate

• all the things an organism wants and can live in

• possible places it can live

• what it is capable of using

• ex. this is the amount of nitrogen that you will give you growth, this is the light you need, this is the soil you like, these are the perfect temps for you

realized niche definition

• portion of fundamental niche that a species actually occupies

• SUBSET of fundamental

• where it actually lives

competitive exclusion

• two species with identical resource requirements can’t coexist

• a competing species can lead to exclusion from overlapping resources

character displacement

• when species that coexist in the same geographic area evovle distinct traits to reduce competition for resources

what can competition lead to

• disruptive selection and character displacement

• this can lead to resource partitioning within a shared fundamental niche

• ex. when both finch species share resources, distributions of beak depths shift to reduce competition

communities are structured around diverse species interactions

changes in the biotic/abiotic environment over time can impact community structure

mutualism

• both species benefit

predation

• one species consumes the other

parasitism

• a species lives on/in another, deriving nourishment

population cycles

• periods of rapid burst and decline of species

• species interactions can lead to dynamic changes in population growth

population ecology definition

• within a speciesc

community ecology definition

• different species interactions

what does it mean when an environment can structure a community

• how abiotic factors are affecting the community

what are resouces

• ALL the things

  • light, amount of N₂, pollinators

  • anything the organism can encounter

competitive exclusion in terms of niches

• how realized and fundamental niche interact in context of competitive exclusion

what happens when 2 species have identitical resource needs

• one will always overcome the other

what happens when 2 species have overlapping resource needs

• find a way to partition the resources and the niche

• can coexist and push the other out of its range

what is changing in order to allow for coexistance

• the niches

what happens first before displacement

• change in resource happens and then the displacement occurs

what DRIVES the character displacement

• the RESOURCES

• because there are no medium sized seeds they move to two extremes

what would happen if there are medium sized seeds

• one of the species already there and would push out the other and force them to eat the small seeds

quantify change in community structure through time

• things that impact community structure can have evolutionary implications too

population cycles can be the result of species interactions

where would disease be in terms of niches

• the realized niche because the fundamental is all ideal things

• real world is no fairytale

can a realized niche be the same size as the fundamental niche?

yes!

species-specific interactions can lead to…

• predicatable changes in population size

• ex. where the hare increases, lynx predators have more food so they increase, then the lynx eats all the hares and then they crash and then there is a crash in lynx, and then the hares would rebound and then cycle repeats

what does it mean when a niche can have “n” axes

• these are all the places someone can live

describe what happens to the niches when partitioning happens

• the realized niche will be narrower than the fundamental when niche/resource partitioning leads to coexistence

what can competition lead to?

• competitive exclusion

OR

• resource partinioning

• it depends on if their resources overlapp or not

biotic and abiotic factors change and that shapes communities

• not just them being there

need to look at each individual species alone and not all together in order to see actual differences in a community

trophic interactions

• associated with how energy is obtained by an organism

• informs movement of energy in ecosystem

• some species fulfill multiple roles

• multiple species in each trophic level

what is more accurate to use to show community interactions

• food webs not pyramids

keystone species definition

• an organism with an impact that is disproportionately larger than its abundance

• has a small # but a LARGE impact

trophic cascade definition

• removal of a keystone species has a big effect

  • directly and indirectly

  • changes ecosystem processes

who are heterotrophs

• detrivores, herbivores, primary predators, secondary predator

who are autotrophs

• plants

bottom up effect

• everything is the same

• fewer plants, fewer herbivores, fewer predators

what is top down effect also

trophic cascade

top down effect description

• fewer predators, more herbivores, then fewer plants

heterotrophs definition

• eat other organisms

• consumers

autotrophs definition

• make their own food

ecological niche

• how an organism uses the resources of its environment

omnivore

• eat autotrophs and other organisms

difference between decomposers and deritivore

• decomposers are a subcategory of a deritivore

does anything happen to the fundamental niche?

• NO, it doesn’t change that is established before anything comes

importance of data literacy

• on the mcat

• crucial for career in science

• helps us be an informed citizen

why do we do data analysis in class

• better to do it than just look at it

• looking at raw data can help us understand

  • data range, standard deviation

  • see outliers

what do autotrophs use

• they use inorganic things

  • like chemicals not actually organims

what do deritivores do

• eat decaying materials

what is seen with a trophic pyramid

• it is about energy and how it moves through the ecosystem

what happens when you move up the trophic pyramid

• there is a reduction in energy

how do we know an organism is a keystone species

• when we lose it

abundant species

• when 90% of the ecosystem is this species and it is affecting interactions and things

difference between abundant and keystone species

• abundant

  • 90% of them and they make a big impact

  • large amount, large impact

• keystone

  • small amount, large impact

how can a trophic cascade change ecosystem processes

• ex. an absent of bass (fish) makes algae form and takes away from oxygen of lake

video example of trophic cascade

• sea otters, the top, decrease

• sea urchins increase and kelp decreases

• if no kelp then nowhere for fish to hide and then they will decrease

• also a decrase in mussell too when no sea otters

  • because there is nowhere to latch since all the urchins are there

are bottom-up and trophic cascade the same

• NO

where is diversity higher

• near the equator

why is diversity higher where it is

• because of

  • climate

    • warmer

  • constancy of condition

    • not dealing with extremes

  • evolutionary age

    • older

  • spatial structure

    • diversity of physical space

what reflects niche availability within communities

• species richness

species richness

• the number of different species present in a community

heterogeneity

• diverse in content

there is feedback between biodiversity and abiotic components of ecosystem

what does species diversity influence

• resource production

• the ability to resist invasion

• recovery from natural disasters

• structure of higher trophic levels

ecosystem function

• things that happen that keep an ecosystem running and healthy

• what the ecosystem does to maintain life

• ecological processes that control the flow of energy, nutrients and organic matter through the enviornment

• how you can help other trophic levels

examples of a healthy ecosystem function

• primary production

• nutrient cycling

• decomposition

biomass

• weight of all the living things

plant species and biomass relationship

higher plant biomass

• which controls for resources

more plant species leads to…

• higher ecosystem stability

  • measured as how much variation there is in mean plot biomass

• and increases resillience after disturbance

intrinsic value of biodiversity

• inspires art & poetry

• tied to spirtuality

ecological value of biodiversity

• biodiversity is correlated with ecosystem function

• supports diversity at higher trophic levels

  • more plants, means more herbivores, which means more predators

ecosystem services

• functions provided by nature that support humans

examples of ecosystem services

• products extracted from ecosystems

• processes that maintain healthy ecosystems

• cultural benefits from ecosystems

estimating the monetary value of ecosystem services can be easy or difficult

• value of ecosystem services is often only reocgnized when they are lost

habitat loss

• threat to biodiversity

• nearly all biomes have experieneced habitat loss

• humans have modified up to 75% of the earth

habitat quality and biodiversity

• anthropogenic activity can reduce habitat quality

• humans can increase disturbance, introduce pollution, reduce connectivity of natural habitats

indicator species

• when something happens to them we know something is going wrong

• ex. frogs are sensitive to water pollution so when they start getting sick then we know something is up

what has happened to the earth in terms of temperature?

• there has been an increase in atmospheric CO₂ and that has led to a mean global temperature increase of 1 degree celcius

impact of incrase of temperature change on biodiversity

• habitats become unsuitable

• resources reduced

• timing of biological events altered

• loss of species interactions

difference between species richness and abundance

• species richness = the different types of species

• abundance = how many individiuals

do all top down effects lead to a trophic cascade?

• no

an increase in biodiversity means more likely to survive because the niches are not all affecting or getting the same treatment

what is the only consistent predictor of biodiversity (& state relationship)

• temperature

• higher temp = more biodiversity

what is a local pattern of diversity

• species richness

  • see this b/c of niche availability and how many diverse niches in an area

can you be highly productive without being diverse?

• yes

  • think invasive species

factors that shape diversity at a local level

• climate

• primary productivity

• habitat heterogeneity

• disturbance

habitat heterogenity

• how different each things are in a habitat

• ex. a corn field not much, but a rainforest a lot

primary production

• the amount of biomass an autotroph makes

• increase rate of this in an ecosystem function

nutrient cycling

• cycling of organic matter

when controlling for resources (give everyone same light, etc), what happens to species and biomass

• as the number of species of plants increases so does plant biomass

• niche partitioning is happening

biodiversity and primary production relationship

• increase in biodiversity means increase in primary production

stability

• ability to withinstand challeneges

what happens if there is a disturbance and there is a lot of biodiversity

• will bounce back because using different niches

hard to put a $ value on an aesthetic part of nature

when did the cambrian explosion happen

535-525 MYA