C6 Change of Ecosystems

1st layer - approx 10-15km high - gets colder further up, air gets thinner - weather + clouds occur in this layer

2nd layer - gets warmer - contains ozone layer (absorbs harmful UV rays from sun) - drier than troposphere

3rd layer - coldest layer - meteors/rock fragments burn up on entry

4th layer - hottest layer - auroras occur within the layer - space shuttle orbits

5th final layer - very thin - made up of He and H

EARTH FORMS (4.6 BYA) - by volcanic activity - very hot - mostly CO2, with N2, some H2O + methane EARTH COOLS - H2O cools, forming oceans - CO2 dissolved into oceans, taken in by organisms - CO2 confined into sedimentary rock + FFs PLANTS EVOLVE (2.7 BYA) - Phs takes in more CO2, produces more O2 - other gases (methane, ammonia) reacted with O2, and decrease in quantity - N is very stable, and has built up over time NOW - atmosphere mostly N2 (79%), O2, with small amounts of H2O, CO2, and other gases

Rock types + locations - rocks in an area give info about past climates (e.g. ancient coral atolls in areas far from oceans) Ancient landscapes (changes/structure) - landscape shapes show climates of the past (e.g. U shaped valleys show the area was glaciated) Fossils - fossils indicate past climates by the organisms that lived there (e.g. ammonites found in a desert, coral found in a forest) Sea/lake evidence - changes in water lvls give an indication of past climate Dendrochronology (tree rings) - tree ring dating indicates whether a climate was wetter (rings are thicker) Historical/archaeological records - cave paintings may suggest species that the current climate would not support (e.g. grazing animals in Sahara) Coral/sediment cores - cores taken from coral/sediments show evidence for climate when they were formed, for 100s-1000s of years ago - combined with fossils, can provide continuous data Atmospheric monitoring - baseline gas conc.s are monitored at: Tas (Sth Hemi), Hawaii (Nth Hemi) - measure greenhouse/ozone depleting gases in clean air enviros - critical for global monitoring Ice cores - very robust evidence - cores drilled from ice caps - past air is trapped in the ice from snow falling, this is analysed - O2 indicates the temp of the past (less heavy O2 means cooler temps)

• winds that circle the Earth near the equator • EAST TO WEST (clockwise)

• predictable changes in atmospheric circulation (weather/wind/clouds) between North Australia and South America • a cycle, around 4-7 years, from which weather predictions can be made • known as a ‘climate driver’ • it oscillates between neutral, El Nino, La Nina SOI (Sthn Osc Index) GRAPH - gives an indication of development + intensity of El Nino/La Nina - larger peaks show when cycle is in El Nino/La Nina

• in the phase more than 1/2 the time • strong trade winds blow E to W • causes upwelling of cold, nutrient dense water in Sth America (good for fishing) WALKER CIRCULATION - warm air over Nth Aus rises - condensation/clouds causes rain - dry air blows on T winds to Sth America - gets cooler, descends - is carried on T winds back to Aus - gets warmer, cycle begins again

• WALKER CIRCULATION INTENSIFIES - the ‘extreme’ version of neutral phase • trade winds are stronger • positive feedback loop (drives itself) AUS - warmer H2O in oceans in Nth Aus - increased rainfall/clouds - atmospheric instability: storms, cyclones, flooding STH AMERICA - colder H2O in oceans - less rainfall, drought - stronger upwelling (good for fisheries)

• TRADE WINDS WEAKEN/REVERSE • warm H2O drifts to Sth America AUS - colder H2O in oceans in Nth Aus - less rainfall, drought, bushfires, heatwaves STH AMERICA - warmer H2O in oceans - increased cloud/rain, flooding - less upwelling (bad for fisheries)

the variety within all species and the ecosystems within they live

• Genetic: differences among individuals/populations, due to sexual reproduction • Species: the variety of different species within an ecosystem • Ecosystem: all the communities, habitats and processes within different ecosystems

INTRINSIC VALUE - everything has the right to exist VALUE TO OTHER SPECIES/ECOSYSTEMS - Genetics variation: increases resilience to change, increases chance of gaining useful adaptations - Habitat variation: provides opportunities for competition, adaptation + evolution, conserving habitats preserves species/genetic diversity HUMAN VALUE - Economic benefits: wide variety of materials, wide gene pool reduces risk of diseases wiping out farmed products, warns us against use of some toxins (e.g. DDT), provides pharmaceutical services - Ecosystem services: pollination, nutrient cycles, pest control via predators, maintain stable atmosphere (CR + Phs)

• 36 identified worldwide • support around half of the world’s plants and animals

• natural events (e.g. ice age, eruptions) Human causes - habitat loss (deforestation, plantations, urbanisation) - invasive species - overharvesting/ hunting / fishing - pollution (damages habitat + organisms) - climate change (many effects: temp change, coral bleaching, frequent fires, etc)

• ecosystems, over millennia, evolve to reach a balance between species interactions • there are limiting factors that restrict the size/range of all species • however, different habitats have different limiting factors • when a species is introduced, the new limiting factors may fail to restrict its growth • results in the species outcompeting all natives • ecosystem may collapse

BIOLOGY - domesticated cat but larger - nocturnal and live almost anywhere - eat any prey they can catch (marsupials, reptiles, rodents, birds etc) INTRODUCED - as domesticated pets in 1800s: escaped into wild - deliberately introduced to control pests (rats, rabbit, mice) Successful: - lack of apex predators in Aus - abundance of prey due to this, not adapted to deal with high hunting efficiency of cats - cats have higher reproduction rates than most Aus marsupials IMPACTS - loss of species: extinction, many under threat - prevents reintroduction programs of species - toxoplasmosis: makes prey lose natural fear of cats, destruction of the population - affects livestock/agriculture populations CONTROL - trapping, shooting, fences to protect areas - baiting (may affect native species) - grooming traps: spray poison onto fur

BIOLOGY - live in most places, create warrens - nocturnal INTRODUCED - 1850S for hunting Successful: - very high reproductive rates compared to natives - high tolerance to lack of water/food - lack of apex predators in Aus IMPACTS - comp with native herbivores: create barren areas, no vegetation - wipe out plant pop.s rapidly - barren soil vulnerable to erosion + infertility CONTROL - fencing, shooting, trapping, exploding/digging up warrens - baiting - myxoma virus (biological control): introduced to deal with rabbits exclusively, there is now some resistance, but still effective - rabbit reproduction is too rapid to ever slow pop. growth

BIOLOGY - fleshy druplets each containing a seed - no natural predators (likely due to spikes) INTRODUCTION - in 1840s, for eating fruit, making hedges, + controlling soil erosion along rivers Successful: - no predators, spikes, many seeds, fast spread IMPACTS - form dense thickets, dominating native species - limit access to areas - decrease land productivity - alter water flow - provide habitat to pest animals CONTROL - leaf rust (biological control): slows growth rate - staged removal: gradually remove + replace with native plants (better for native animals using plants as shelter) - goats (invasive) eat blackberries - herbicides (animals may eat the fruit and be affected)

BIOLOGY - herbivores with long spines - lives on rocky coastlines - females produce millions of eggs a year INTRODUCTION - climate change and warming waters - allowed urchins to move further south + reproduce more Successful: - overfishing of large crayfish (their only natural predator) - the legal catching size is smaller than they need to be to kill an eat an urchin IMPACTS - overgrazing of kelp/coral: reduces habitat for native species, prevents absorption of CO2 from water, increases climate change - grazing creates barren areas of no life CONTROL - culling or urchins by hand by divers - establishing a market for eating urchins - increasing populations of crayfish by dropping into areas - reducing number/size of crayfish caught

IN SITU - conservation of species in their natural habitat (nature parks, reserves) EX SITU - conservation in isolation to their natural habitat (botanic parks, zoos, seed banks)

PURPOSE - conserve species in their natural environment PROS - species have all their required resources - more space - greater genetic diversity - evolution will occur - cheaper to maintain - non-target species will be protected due to species interactions CONS - large land may be hard to manage/police from illegal actions - land may need restoration - invasive species may affect the ecosystem - edge effects if the land is small (design/shape of the land may not be efficient)