module 4 ecosystem dynamics

Question 1

megafauna extinction

Answer 1

megafauna in australia
climate change
- ice age dried out aus
- rainforest retreating // replaced by eucaltyps
- arid climate
- bushfires

for
- large animals need lots of water

against
- ice ages prior didn’t have the same effect
- today climate change doesn’t impact only slow fast moving animals

human intervention
- introduction of fire as a hunting tool
- slower > easier to kill

for
- use of fire supports increased carbon deposits on fossils around age age

against
- no kills sites

soil nutrients
- lack of soil nutrients
- domino effect on rest of ecosystem and food web

Question 2

capture recapture

Answer 2

m/n = r/t

Question 3

evidence of past ecosystems

Answer 3

Aboriginal and Torres Strait rock paintings
Wes Kimberley rock paintings
Bradshaw drawings
animals like the tasmanian tiger, and goana can be seen
analysing dates of drawings through radiometric dating via isotopes of uranium

Keep river > more reptile > wetter environment

BIFS
cyanobacteria > photosynthesise
release oxygen forming iron oxide which precipitates and forms sedimentary rock
shows when o2 is realesd into waters and atmosphere
allowing animals to move onto land

gas analysis in ice cores
- identify adn analyse levelfs of gasses in atmosphere
higher c02 warmer climate
- compare o18 o17 o16 isotopes to current day

radiometric dating
half life of isotopes to date fossils

Fission track dating

fossils
cast
organism
trace

Question 4

present day organisms evolved from organisms in the past

Answer 4

small mammals
placental mammals - higher metabolism more resources required
died due to changing climate
marsupials - lower gestation period
allowing marsupials to dominate the niches

monotreams
spread all along gondwana
sea level rise - geo isolation
became aquatic - dominate that niche as marsupials didn’t go into the waters

sclerophyll plants
aus split from ant
moving north east
more arid
more drought
more fires

due to impact of el nino

+ more fire due to introduction of humans

sclerophyll
woody plants with thick evergreen leaves reduce water loss

prior to split rainforests dominated
fossils found across Gondwanaland
analysis of pollen + charcoal

Question 5

recent extinction events

Answer 5

thylacine
carnivore
dingoes outcompeted the,
dogs introduced
fossils and photo evidence

moa
flightless
megafauna
herbivores
human - killed for warmth + food
large deposits of bones - kill sites
maori oral history and storytelling

Question 6

human induced selection pressures - impact and innovations to prevent this

Answer 6

eutrophication
- bad
- stopped by stripping and processing fertilisers to reduce impact

salinisation
- caused by flood irrigation
reduce soil biota
impact osmotic mechanisms in root hairs
- stopped by desalination - reverse osmosis
+ drip irrigation

pesticide residue
- impact non target species
stopped by
other pest management systems not chemical - gmo - reisstant to pests - make them taste badly to pests for use traps and barriers

Question 7

sunnyside mine

Answer 7

soil
test soil
pH
salinity
reguarly

water
runoff - non polluting
infrastructure impacting waterways removed
discharge wastes appropriately not into water ways

biodiveristy
ensure biodiverity maintaned by regualting pest species
ensuring native species are at a suitable abundance relative to benchmakr and local reference analogue
woodland rehabilitation to connect woodlands in surrounding areas
koala habitat