Ecology

  • biodiversity - variety of life in all of its forms

    • ecosystem diversity - variety of ecosystems found in an area/on earth

    • species diversity - number/relative abundance of species found in an ecosystem

    • genetic diversity - variety of genes/alleles present in a species

      • high genetic diversity → more likely to survive changes in environment

        • via natural selection

    • measured through ecological surveys of wide range of habitats

  • number of species fluctuated over time

    • there have been at least 5 mass extinction events

  • anthropogenic species extinction - loss of species due to human activities

    • humans are causing a 6th mass extinction

      • habitat destruction

      • climate change

      • pollution

      • overexploitation (overhunting)

      • invasive species

      • disease

  • Giant moas - large flightless birds that lived on new zealand

    • had few predators before humans

    • Maori people hunted them for food, clothing, and jewelry

      • overexploited/overhunted → extinct

  • caribbean monk seal

    • hunted to extinction for meat, clothing, blubber by humans

      • also damaged breeding sites

  • one of the biggest causes of biodiversity loss = destruction of habitats/ecosystems by ppl

  • mixed dupterocarp forest

    • some of the most biodiverse ecosystems on earth

    • loss from human activities

      • deforestation - hardwood timbers

      • agriculture - development of palm oil plantations

      • mining - excavation for mining coal, metals, and diamonds

      • climate change - result in floods + droughts

      • hunting - reduces biodiversity + disrupts ecological balance

  • mangrove ecosystem

    • loss from human activities

      • coastal infrastructure + tourism

      • agriculture - farms upstream release harmful chemicals into mangroves

      • fishing + aquaculture - overfishing removes links in food change + eutrophication

      • climate change - mangroves cannot tolerate more salt water from higher tides

  • biodiversity should consider richness + evenness

    • richness - number of different species

    • evennes - relative population numbers of each species

    • should have a wide variety of different species

  • simpson’s reciprocal index - measure of biodiversity in an ecosystem

    • high index value → stable site w many different niches

    • index value may decrease in response to ecological disturbance

    • low index value → site w few potential niches where only few species dominate

  • benefits of citizen science

    • increases quantity of data

    • cost effective

    • increased public engagement in conservation

  • challenges

    • data quality

    • bias

  • over-exploitation of resources - unsustainable use of resources

    • disrupts food webs → decrease in biodiversity

    • poaching/irresponsible hunting

    • overfishing

    • logging

  • urbanization - movement of people to cities and towns

    • leads to loss of ecosystem biodiversity

  • deforestation

    • happens due to demand for wood + agricultural land

    • destroys ecosystems + biodiversity → climate change

  • agriculture

    • farm wastes, fertilizers, pesticides enter ecosystem → disrupt food webs + biodiversity

  • pollution - introduction of harmful substances into environment

  • invasive species - introduced species harm their non native ecosystem

    • brought by global transport

      • also pests + diseases are brought

  • species conservation

    • ex situ conservation - conservation outside of natural habitats

      • zoos, botanical gardens

      • ex. espanola giant tortoise

        • in danger of extinction via competition w goats + overhunting

        • tortoises entered captive breeding program

        • goats removed from island

        • tortoises reintroduced

      • seed banks - store seeds to preserve genetic variety

      • tissue banks - store plant tissues to propagate future plants

      • advantages

        • protection from predators

        • greater control of conditions → ensures that offspring survive after birth

        • IVF can increase offspring

      • disadvantages

        • captive populations have limited genetic diversity

        • organisms living outside natural habitat → may not have required survival strategies when reintroduced

        • does not prevent destruction of og habitat

    • in situ conservation - conservation inside of natural habitats

      • management of nature reserves

        • nature reserve - protected ecosystem managed for conervsation

          • endangered species often kept to protect from poachers

      • rewilding + reclamation of degraded ecosystems

        • aims to restore degraded ecosystems back to natural state

          • regenerate biodiversity

      • restoration of ecosystems

      • removal of invasive species

      • reintroduction of locally extinct species

      • legal protection against pollution/development

      • controlling access to ecosystem

      • controlling poaching

      • advantages

        • organisms not in captivity → survival strategies

        • other species in protected habitat also protected

        • biodiversity

      • disadvantages

        • endangered species need large areas for population survival

        • difficult to prevent poaching

        • genetic variety may already be damaged

  • Evolutionarily Distinct and Globally Endangered (EDGE) Program - identifies species to conserve

    • evolutionary distinctiveness - species are unique and has few/no close relaitves

    • global endangerment

      • based on IUCN red list

        • identifies threat level of extinction for a species

  • ecology - biology dealing w relationships btwn organisms + environment

    • organisms - any individual life form

      • have at least 1 cell

  • habitat - natural home/environment of an organism

    • must provide all resources an organism needs to survive

    • ex. coral reefs

  • descriptions of habitats

    • geographical location

      • latitude, longitude, climate

    • physical location - characteristics of the geographical area

      • landforms, water bodies, vegetation, microhabitats

    • type of ecosystem - broader ecological community

      • species interact w other species + abiotic environment

  • species - group of organisms capable of reproducing with each other to produce fertile offspring

  • population - one species in one location in one time

  • community - populations of different species living and interacting w each other in a habitat

    • interactions include

      • predator + prey

      • herbivory

      • competition for resources

      • mutualism

      • parasitism

  • ecosystem - location where a community of organisms interact w each other + abiotic environment

    • abiotic environment - nonliving environment

      • air, minerals in soil, light, climate

  • adaptations - any heritable traits that make an organism better able to survive + reproduce

    • Marram grass - adapted to little water (xerophytes)

      • leaves roll into a tube w stomata inside

        • air trapped inside → maintains high humidity outside stomata → reduce transpiration

      • sunken stomata w fine hairs

        • traps moist air outside stomata → reduces transpiration

      • thick waxy cuticles on leaves

        • reduces evaportion

      • long/deep roots

        • aid in search of water

      • extensive roots near surface

        • helps sand retain water

    • mangrove trees - adapted to waterlogged, anoxic soil + high salinity

      • prop roots descend from trunk

        • provide tree w stability

      • widespread shallow root system

        • provides additional support

      • aerial roots (pneumatophores)

        • low tide → gas exchange occurs through open passages → air transported to underground roots

      • salt filtration

        • plasma membranes of roots prevent salt from entering

  • Shelford’s Law of Tolerance

    • organisms have optimal survival rates for abiotic factors

    • an organism moves away from optimum conditions → decrease in survival rates

      • optimum range - max survival rates

      • zones of stress - reduced survival rates

      • zone of intolerance - organisms cannot survive

  • variables affecting the distribution of organisms

    • temperature

    • ph

    • available minerals + light

    • altitude

    • latitude

    • humidity

    • soil content

    • breeding sites

    • aeration of soil

    • climate

  • belt transects - investigate relationship btwn distribution of species w an abiotic factor

  • coral reefs - sessile animals w a mutualistic relationship w zooxanthellae

    • water clarity

      • need clear water

    • water depth

      • grows best at 50 m to allow light to penetrate zooxanthellae

    • temperature

      • 16C - 34.5C

    • pH

      • 8 - 8.3

    • salinity

      • 23 - 42 ppt

  • biomes - naturally occurring communities of organisms occupying a major habitat

    • tropical forest

      • high rainfall + temperatures

    • temperate forest

      • hot summers + cold winters

      • moderate rainfall

    • grassland

      • low rainfall

    • hot desert

      • hot days + cold nights

      • very low rainfall

    • taiga

      • cold/snow winters + warm/humid summer

      • low precipitation (snow)

    • tundra

      • frozen a lot of the time

      • short summers

      • low precipitaiton

  • whittaker’s climograph - predicts terrestrial biome found in a location according to mean annual temperatures and mean annual precipitation

  • convergent evolution - independent evolution of similar features in different species

  • adaptations of desert plants

    • succulence - fleshy stems + leaves = water storage

    • reduced leaf surface

      • reduce transpiration

    • deep root systems

      • access groundwater

    • CAM Physiology - stomata close during day and open at night

    • thick waxy cuticle

      • reduces evaporation

  • saguaro cactus

    • thick waxy cuticles

    • spines

      • reduce surface area for transpiration

      • protection

    • water storage

    • widespread root system

  • adaptations of desert animals

    • nocturnal behavior

    • efficient water conservation

      • concentrated urine

    • efficient metabolism

      • low

    • camouflage

    • long loops of henle

  • Camels

    • water conservation

      • concentrated urine

    • fat storage

      • fat can be metabolized when sustenance scarce

    • large SA:V ratio

      • efficient heat loss

    • high temperature tolerance

    • long legs

      • above hot sand

    • long nasal passages

      • trap + reabsorb moisture from air

    • broad feet

      • walk over sand

  • adaptations of plants in tropical rainforests

    • buttress roots

      • provide stability + absorb nutrients

    • drip tips

      • allow water to run off

    • epiphytes

      • grow on trees

    • lianas - vines that grow on trees to reach light

    • mutualistic relationships

  • dipterocarp trees

    • tall

    • fast growth rate

    • buttress roots

    • large leaves

    • lots of fruit

      • seed dispersal

    • chemical defenses

  • adaptations of animals in tropical rainforests

    • arboreal adaptations

      • tails, grasping hands/feet, strong limbs

      • acute sesnses

      • camouflage

  • sumatran orangutans

    • long arms + grasping feet

    • opposable fingers and toes

    • color vision

      • see food + predators

    • camouflage

    • intelligence

    • strong jaws and teeth

  • ecological niche - role of an organism in an ecosystem

    • includes abiotic and biotic factors that affect

      • growth + survival

      • reproduction

      • mode of nutrition

      • interactions

  • obligate aerobes - cannot survive in presence of oxygen

    • anaerobic respiraton

  • facultative anaerobes - survive with or without oxyegn

    • aerobic or anaerobic

  • obligate aerobes - cannot survive in absence of oxygen

    • aerobic respiration

  • autotrophs - produce own food

  • heterotrophs - must take food from other organisms

    • holozoic nutrition - ingests + internally digests food

    • saprotrophs - external digestion via enzymes

      • ex. bacteria and fungi

  • mixotrophs - can be autotrophs and heterotrophs

    • ex. Euglena

    • obligate mixotrophs - need both to survive

    • facultative mixotrophs - can switch based on resources

  • archaea - metabolically diverse prokaryotes

    • phototrophs - use light to produce atp BUT no oxygen produced

    • chemolithotrophs - oxidize inorganic compounds to make ATP

    • organotrophs - oxidize organic compounds to make ATP

  • herbivores - have flat teeth + strong jaws

    • homo floresiensis

    • paranthropus robustus

  • omnivores - mixture of sharp teeth + flat molars

    • homo sapiens

  • plant adaptations against herbivores

    • physical structures (ex. thorns)

    • sharp trichomes w chemicals

    • tough/fibrous leaves

    • capsaicin

    • nicotine

  • adaptations of grazing mammals

    • flat molars

    • teeth grow forever → do not wear down

  • adaptations of insects

    • sharp mandibles w serrated edges

      • cut through cell walls

    • strong muscles in mandibles

    • piercing mouth pieces

      • stylets → insert into phloem → obtain nutrients

  • predator adaptations

    • physical

      • sharp claws/alons

      • powerful jaws/teeth

      • speed

      • camouflages

    • chemical

      • venom

    • behavioral

      • hunting in a pack

      • ambush tactics

  • prey adaptations

    • physical

      • armour/protective cover

      • swift

      • camouflage

      • mimicry

    • chemical

      • toxic/unpalatable chemicals

        • brightly colored

    • behavioral

      • travel in groups

      • swarms

      • alarm calls

      • nocrutnal/diurnal

  • plant adaptations for harvesting light

    • trees reaching canopy

    • lianas

    • epiphytes + strangler epiphytes

    • shade tolerant shrubs/herbs growing on forest floor

  • canopy trees

    • height/crown structure

    • broad leaves

  • liana vines

    • climbing mechanisms

    • rapid growth

    • flexible/thin stems

    • large broad leaves

  • epiphytes - plants growing on another plant

    • grow on canopy trees

    • broad flat leaves

    • flexible growth

  • strangler epiphytes - germinate in branches of canopy trees but send roots to floor

  • shade tolerant plants

    • branching

    • broad leaves

    • lots of chlorophyll

  • ecological niche - role of an organism in an ecosystem

  • fundamental niche - niche an organism COULD occupy without competition

  • realized niche - niche an organism occupies BECAUSE of competition

  • competitive exclusion - no two species occupy the same niche

    • one is better adapted → outcompetes → other species eliminated

    • ex. red and grey squirrels in the UK

  • population - one species in one location at one time

    • have to be reproductively isolated

      • reproductive isolation - a barrier stops individuals from reproduction

  • Sampling - estimate population size

    • not enough time to count

    • collecting data may damage habitat

    • counting is not feasible

    • quadrat sampling - estimates population of plants + sessile animals

    • random

      • representation

      • removes bias

      • generalization

  • Capture-mark-release - estimates population of motile animals

    • random sample captured + counted (M)

    • captured individuals marked + released

    • second sample of population captured + counted (N)

    • number of recaptured mark is counted (R)

    • lincoln index formula

  • Carrying capacity - max population size of a species that cen supported long term in an environment

    • based on

      • availability of food + water

      • space

      • shelter

      • disease + predators

      • climate

  • factors affecting population growth

    • density independent - not based on population size (abiotic)

      • climate events + natural disasters

      • habitat destruction

      • seasonal changes

    • density dependent - based on population size (biotic)

      • competition

      • risk of predation

      • disease

  • 4 factors affecting population growth

    • natality (birth)

    • mortality (death)

    • immigration (entering)

    • emigration (leaving)

    • change in population size = (natality + immigration) - (mortality + emigration)

  • exponential growth = environment with limited competition

  • sigmoid growth curve = environment with competition

    • exponential phase

    • transitional phase

    • plateu phase

  • intraspecific competition - competition btwn members of the same species

    • all have the same ecological niche

    • increases due to density dependent factors

    • territory for food + reproduction

    • mates

    • social dominance

  • intraspecific cooperation - benefits all members of a population

    • increases population’s access to resources + protection from predators

    • group hunting + foraging

    • defense against predators

    • parenting

  • community - populations of different species living/interacting w each other in an ecosystem

    • herbivory

    • predation

    • interspecific competition - different species compete for same resources

      • leads to competitive exclusion or species having different ecological niches

    • mutualism - close relationship btwn two different species (symbiosis)

      • both individuals benefit

    • parasitism - one species benefits, another is harmed

    • pathogenicity

  • examples of mutualism

    • root nodules in Fabaceae

      • nodules w nitrogen fixing bacteria

      • plants unable to synthesise nitrogen compounds

      • bacteria give nitrogen compounds to plants → plants give organic compounds + carbs to bacteria

    • mycorrhizae

      • roots of plant + fungus

      • orchids increase SA for absorption of water/materials

      • fungi enhances orchids ability to get nutrients

    • zooxanthellae and coral

      • zooxanthellae are photosynthetic

        • produce glucose for coal

        • remove wastes

        • produce oxygen

      • coral protects zooxanthellae + gives CO2

  • alien species - organisms introduced to an ecosystem

    • can become invasive if cause harm

      • replace endemic species via competitive exclusion

        • absence of predators + disease

        • faster reproduction

        • larger + more aggressive

        • outcompeting food + resources

  • positive assocation - two species are likely to be found together in an ecosystem

  • negative association - two species are not likely to be found together

  • chi squared tests of association

    • null hypothesis - no significant association (P > 0.05)

    • alt hypothesis - significant association (P < 0.05)

    • Steps

      • construct table of observed frequencies for 2 species

      • construct table of expected values

      • calculate column + row totals

      • formula

      • calculate chi squared

      • determine degrees of freedom

      • determine if P > or < 0.05

        • if calculated < table → null hypothesis

        • if calculated > table → alt hypothesis

      • determine association

  • top down controls - pressures applied at higher trophic levels to control ecosystem dynamics

    • predator prevents prey overpopulation

  • bottom up controls - resources available to producers that affect their growth

  • allelopathy - release of chemicals by an organism that influences germination, growth, survival, or reproduction of another

    • black walnut trees produce juglone → inhibits growth of many plants

      • reduces competition

    • penicillium fungus secretes penicillin → stops bacteria growing

      • reduces competition

  • communities form ecosystems via interactions w abiotic environment

    • ecosystems = open systems where energy + matter and leave

    • earth = closed system

      • energy exchanged w surroundings outside planet

      • matter is not

  • most ecosystems depend on sun as principal source of energy

    • autotrophs use energy to photosynthesize

    • heterotrophs eat autortrophs

  • some ecosystems do not use sun

    • hydrothermal vent ecosystems

      • producers = chemoatuotrophic bacteria

    • deep sea ecosystems

      • producers = chemosynthetic bacteria

    • cave ecosystems

      • rely on organic matter from outisde cave

      • also chemoautrotophic bacteria

  • energy flows from producers → consumers

  • Food chains - shows feeding relationship btwn organisms in an ecosystem

    • arrow = energy + biomass transfer

    • always begin w producer

    • food webs - interlocking + interdependent food chains

  • decomposers - organisms that get energy from dead organisms

    • saprotrophs - heterotrophs that externally digest dead organisms

      • ex. fungi

    • detritivores - heterotrophs that internally digest dead organisms

      • ex. worms

    • consume faeces, dead parts of organisms, and dead organisms

  • autotrophs - producers who use external energy to make their own food from inorganic substances

    • photoautotrophs - use light

    • chemoautotrophs - oxidize inorganic compounds

      • iron oxidizing bacteria - oxidize ferrous ions to ferric ions

  • organisms release energy from food → use it for metabolism → provide energy for anabolic reactions → build macromolecules

  • heterotrophs - organisms use carbon compounds from other organisms to synthesize food

    • saprotrophs - externally digest dead organisms

    • detritivores - internally digest dead organisms

    • consumers - internally digest living organisms

    • digestion = hydrolysis reactions

      • carbon compounds assimilated → synthesize carbon compounds via condensation

  • trophic level - position an organism occupies in a feeding sequence

    • many species occupy different trophic levels

    • pyramid of energy - shows flow of energy through an ecosystem

    • 90% of energy is lost btwn trophic levels

      • organisms lose energy in forms of heat during respiration

      • organisms die before being eaten → energy not available to next level

      • some parts of organisms are not eaten

      • some parts are indigestible (ex. cellulose)

      • loss of energy restricts the number of trophic levels in ecosystems

        • each stage in food chain has less total biomass → less energy available to organisms at higher levels

  • source of energy for most food chains = sun

    • autotrophs get light energy → photosynthesis → carbon compounds

    • consumers eat autotorphs/other consumers

    • most (90%) of energy lost as heat btwn trophic levels

    • decomposers get energy from dead plants/organisms

  • productivity - rate of generation of biomass in an ecosystem

    • primary productivity - producers synthesizing compounds to create biomass

    • secondary productivity - heterotrophs feeding to increase biomass

      • always lower than primary productivity

    • productivity varies per biome

      • tropical rainforests get more rain + high temperature → plants grow fast

      • deserts have a lack of water → plants grow slowly

    • low primary productivity → reduces secondary productivity

    • loss of CO2 = loss of biomass

  • Carbon cycle

    • to air

      • combustion

        • fossil fuels

        • forest fire

      • cellular respiration

        • decomposers

        • consumers

        • producers

    • to producers

      • photosynthesis

    • to consumers

      • eating producers

      • feeding on each other

    • to bacteria/fungi

      • death of producers + consumers

    • to fossil fuels

      • incomplete decomposition + fossilization

  • carbon sinks - absorb co2 from atmosphere

    • ecosystems where photosynthesis exceeds respiration

      • net uptake of CO2

    • examples

      • fossil fuels (peat, coal, oil, natural gas) in distant past

      • formation of biomass (wood) currently

  • carbon sources - release co2 into atmosphere

    • ecosystems where respiration exceeds photosynthesis

      • net release of CO2

    • examples

      • combustion of biomass, peat, coal, oil, natural gas

      • human activities

        • combustion of fossil fuels

  • Keeling curve - shows change in earth’s atmospheric co2 concentrations

    • most landmass + plants in northern hemisphere

      • summer/winter in northern hemisphere → greater impact on keeling curve

    • photosynthesis peaks in summer → more CO2 removed from atmosphere

    • photosynthesis decreases in winter → more CO2 added to atmosphere

    • general increase in atmospheric CO2 since 1940s

      • human activity

  • heterotrophs require oxygen produced by autotrophs for aerobic respiration

  • autotrophs require CO2 produced by heterotrophs for carbon fixation

  • all chemical elements are cycled within ecosystems

    • decomposers release chemical elements from dead organisms back into ecosystems

    • loss of chemical elements → reduces productivity

  • many ecosystems are stable without human activity

    • tropical rainforsests - millions of years

    • desert ecosystems - 60 million years

  • requirements for stable ecosystems

    • supply of energy

    • recycling nutrients

    • genetic diversity

    • climatic variables within tolerance levels

  • tipping point - critical threshold that when crossed = large/irreversible changes in the climate system

    • ex. brazilian forests may be at tipping point for climate change

      • generate atmospheric water vapor via transpiration → cools atmosphere → impacts air flow + rainfall

      • rain forests = carbon sinks

      • 20% of amazon rainforest been deforested

        • impact wind + rainfall → climate change

  • mesocosms - indoor environmental systems mimicking a natural environment under controlled conditions

    • allow to control/manipulate variables while investigating ecosystems

  • keystone species - species w a disproportionate effect on the structure of their community

    • ex. wolves in yellowstone

  • harvesting < replacement → harvesting plants/fish from ecosystem = sustainable

    • must have sufficient adult organisms to ensure enough offspring

    • commercial fishing usually not sustainable

      • sustainable fishing - harvesting fish where fish population does not decline over time

        • ex. alaskan cod

      • maximum sustainable yield - largest catch of fish that can be sustained without causing fish stocks to decrease

    • ex. silver top palms

    • remove leaves → harvest without killing plant

  • sustainable farming - agricultural production that meets current needs of food production + preserving natural environment

    • factors affecting sustainable farming

      • soil erosion

      • leaching nutrients

        • eutrophication - a body of water becomes enriched w nutrients and leads to algal growth

          • algal growth → increase biological oxygen demand

            • may become anoxic → animals die bc of low oxygen levels

          • prevents sunlight reaching plants in lake → plants die

          • nutrient levels decrease → algae dying

          • dead plants + algae accumulate → aerobic bacteria decompose

      • supply of fertilizers + other inputs

      • pollution bc of agrochemicals

      • carbon footprint

  • biomagnification - increase in concentration of a substance in tissues of organisms at successively higher levels in a food chain

    • ex. DDT

      • used to kill insects

      • does not readily break down in fat tissue

      • insects → fish → birds (ospreys)

      • causes shells to be very thin → shells break → offspring dead → osprey population decreases

    • ex. Minamata disease - neurological disease caused by biomagnification of methylmercury

      • mercucry released into manamata bay by chemical factory → bacteria turn it itno methylmercucry

      • plankton → fish → people

  • macroplastics - large visible debris

  • microplastics - produced by physical breakdown of macroplastics

  • evidence that consumption of plasitc → killed many Laysan albatrosses

  • sea turtles eat plastic bags → plastic becomes lodged in oseophagus → feeding problems

  • rewilding - aims to restore degraded ecosystems back to normal

    • reintroduction of keystone species

    • reestablishing connectivity of habitats through wildlife corridors   

      • wildlife corridors - areas of habitat connecting wildlife populations separated by human activities/structures

        • allow

          • migration

          • expanding habitat range

          • increasing biodiversity

          • greater genetic variety

    • management of ecosystems to reduce human impact

      • Hinewai Reserve - goal to regenerate native vegetation + wildlife

  • ecological succession - process of change in an area of a period of time caused by complex interactions btwn organisms and the environment

    • primary succession - begins when an area of ground/bare rock with no existing soil is colonized

      • after volcanic eruptions/retreat of glaciers

      • ex. glacier bay national park

        • glacier retreats → bare rock

        • pioneer species colonize → pioneer dies → soil quality improves

        • pioneer species replaced by other communities → more soil improvement

        • woodland of alder trees present

          • replaced by a climax community → reduces pH → bad soil

            • climax community - ecological community where populations of organisms stay stable + exist in balance w each other/environment

              • final stage of succession + remains unchanged

    • secondary succession - started by a disturbance that reduces an already established ecosystem to a smaller community of species

    • abiotic factors involved

      • natural disturbances

        • retreating glacierss

        • forest fires

      • changes to soil composition

        • nutrient deposition

        • weathering

        • pollution

      • geolocial changes

        • soil erosion

    • biotic factors involved

      • pioneer species

        • modify environment → lets new species colonize

      • species competition

      • predation and prey cycle

      • keystone species

    • changes that occur during succession

      • size of plants

        • small → big

      • primary production

        • biomass increases over time

      • species diversity

        • increases

      • complex food webs

        • increases

      • nutrient cycling

        • soil builds up → more nutrients recycled

    • cyclical succession - community is changed by recurring events/changing interactions w species of plants/animals

      • ex. wildfires

        • plants have adaptations

          • lodgepole pines produce serotinous pine cones → release seeds after extreme heat

      • always secondary succession

    • arrested succession - natural progression of plant species is halted due to human activity or other factors

      • grazing livestock

        • eat vegetation that could grow more

        • reduces biodiversity

      • draining wetlands

        • less water → dryer soil

        • less biodiversity

  • anthropogenic climate change - climate change caused by humans

    • combustion of fossil fuels + wood → co2

    • farming cows, sheep, rice → methane

    • more co2 + methane → increase in global temp

      • greenhouse gases

  • climate change - long term shifts in temp + weather

  • positive feedback loops increase global warming

    • snow + ice

      • snow + ice reflect solar radiation

      • snow + ice melt → dark land/water exposed → absorb solar radiation as heat → more global temp

    • decomposition of permafrost

      • permafrost stores carbon

      • permafrost thaws → peat is decomposed → releases CO2 + methane → keeps heat

    • release of carbon dioxide from deep ocean

      • oceans = carbon sinks

      • temperatures increase → volume of CO2 that can dissolve in water deccreases + co2 released from oceans back to atmosphere

    • alterations in precipitation

      • more drought + dry condition → forest fires more liekly → release CO2

  • boreal forests = carbon sink

    • carbon stored underground

      • low temp → less decomposition

    • warm temperatures + decreased snowfall

      • more droughts → reduces primary productivity → volume of CO2 removed decreases

    • forest browning

      • drought → leaves turn brown

      • increases frequency + intesnity of wildfires

  • decreasing trend in area of arctic sea ice over time

    • landfast ice + sea ice melting

    • emperor penguins need sea ice to form breeding colonies

      • less sea ice → less emperor penguin colonies

      • sea ice melts before chicks can swim

    • walruses use ice floes for resting + feeding young

      • loss of ice floes → affect ability to hunt + feed young

      • walruses rest on beaches further from food

        • stampede of walruses → young walrsuses crushed to death

        • travel longer to get food → more difficult to feed young

  • nutrient upselling - cold nutrient rich water rises from bottom to surface of ocean

    • brings nitrate + phosphate to phytoplankton on surface

      • high primary productivity of phytoplankton → supports biodiversity

    • climate change

      • changes in wind patterns

        • changes frequency + extent of nutrient upwelling

      • alteration of ocean circulation patterns

        • alters frequency + extent

      • warm water prevents upwellings if there is no wind

    • no nutrient upwelling → primary productivity decreases → phytoplankton productivity decreases → decrease in biodiversity

  • species adapted to specific climates → climate change → range of species changes

    • move up to higher elevations

    • ex. birds in new guinea

      • birds move range to cooler/higher altitudes on mountains in new guinean montane forests

      • bird populations decreasing at lower altitudes

      • upslope range shift

        • birds move upslope → habitat is compressed

    • ex. north american trees

      • move northward to cooler climates

      • poleward range shift

        • contracts overall range of many north american tree species

  • coral reefs - one of the most biodiverse marine ecosystems

    • under threat

      • ocean acidification   

        • more co2 coming into oceans → lower pH

          • co2 + water = carbonic acid

          • carbonic acid dissociates → H+ ions

          • H+ ions react w carbonate ions → hydrogen carbonate → reduces carbonate for corals to make their exoskeletons

      • coral bleaching bc of higher water temperatures

        • corals have mutualism w zooxanthellae

          • zooxanthellae give coral nutrients via photosynthesis

          • higher temperature → zooxanthellae dispelled → lose color (bleached)

          • danger of starvation

      • collpase of coral reef → extinction of many ocean species

  • carbon sequestration - process of capturing + storing atmospheric CO2

    • plants remove co2 during photosynthesis

    • carbon in biomass of plants as carbon compounds

    • plants die + decompose → carbon sequestered in soil

      • in peat wetlands → carbon stays sequestered in soil bc of acididity

        • carbon sink

    • more ways to sequester carbon

      • afforestation

        • establishing forests where there isnt tree cover

      • forest regeneration

        • regrowing a forest after a disturbance (reforestation)

      • restoration of peat wetlands

        • peat - forms when organic matter is not fully decomposed because of acidic or anaerobic conditions in watterlogged soil

  • phenology - study of cyclic + seasonal natural phenomena

    • flowering - plants produce flowers

    • budburst - emerging of new leaves

    • bud set - cessation of bud growth

    • migration

    • nesting

    • plants use changing temp/photoperiods to influence biological processes

      • photoperiod - length of time in a day an organism recieves light

  • interactions btwn species disrupted by climate change

    • global warming disrupts timing of biological events for temp but not photoperiod

      • ex. reindeer and arctic mouse eared chickweed

        • chickweed growth determined by increasing temp in late spring/early summer

        • migration of reindeer determined by photoperiod + move north in early spring

        • chickweed grows earlier → less chickweed available as food for migrating reindeer when they arrive

      • ex. great tit + caterpillar biomass

        • hatching of great tit offspring matches abundance of caterpillars in spring

          • caterpillar = important food source for birds + offspring

        • hatching = trigger for great tit egg laying

        • increasing temperature = trigger for growth/development of caterpillars

        • peak biomass of caterpillar comes earlier → offspring hatch after peak caterpillar biomass → shortage of food → number/mass of offspring produced by great tits decreased

  • spruce bark beetles eat spruce trees → infestation kills spruce trees

    • warmer temperatures → spruce bark beetles complete life cycle in 1 year instead of 2 → reproduce more frequently → increase in spruce bark beetle population → death of more spruce trees

  • plumage of owls

    • tawny owls → genetics

      • grey or brown

    • evolution

      • selection presures

        • decreasing snow cover bc of climate change

      • genetic variation

      • intraspecific competition

        • produce more offspring than environment supports → competition

      • favorable adaptation

        • brown more likely to survive mild winters

          • better camouflage

      • survive + reproduce

        • brown more likely to survive than grey

      • genetic inheritance

        • brown is favorable → more likely to be passed down

      • natural selection

        • frequency for brown increases over time