Ecosystems and Environmental Change Flashcards

This set of vocabulary flashcards covers ecological sampling techniques, human environmental impacts, and evidence for past ecosystems based on the lecture transcript.

Quadrants

-Tools used to measure the abundance of non-mobile organisms using the Lincoln index formula formula:

-Placed randomly to get more representative results without bias that misrepresents population size

-Can be found counting the number of organisms in each square or percentage cover

-Repeating sample measurements and placing more samples increases reliability and makes the estimate more representative as it accounts for outliers to have smaller affect on the average

Transects

Method that includes quadrants to determine the distribution of sessile organisms and the abiotic factors that come into affect

Belt transects

Continuous quadrants across area to determine distribution. Provides more representative results but is more time consuming

Interrupted transects

Quadrants placed at regular intervals along a line to measure distribution with greater time efficiency.

Line transects

Method of data where distribution is measured across a straight line, typically using tape.

Mark, release, capture method

-A technique used to measure the abundance and distribution of mobile organisms.

-Organisms are captured in a particular area for a particular amount of time and are all marked

-The trap is set in the same place for the same out of time a week later, Lincoln’s index provides a rough estimate of population

Ethical considerations/Drawbacks of Mark, release, capture method

-This can’t be tested on endangered species as it risks population decrease

-Marking needs to be subtle to not attract predators and cause disruption to ecosystem patterns

-Some organisms may learn to avoid the trap, providing less representative results

Lincoln Index

A formula used to estimate population size: $N = \frac{M \times n}{m}$ , where $M$ is the number marked, $n$ is the number captured, and $m$ is the number of marked individuals in the recapture.

How does Forest fragmentation induce selection pressures

-Dangers when travelling across patches

-Decrease in population size as species get separated and can’t breed as much

-The edge affect: Mobile organisms relocate to the edges of fragments for easier acsess to resources and vegetation, as well as reduced humidity

Define invasive species

Non-native species introduced to an environment that reproduce and spread in a way that damages the ecosystem.

How can invasive species spread and affect ecosystems

-They can spread after devasting habitat destruction, a variety of resources and temporal conditions

-They can create competition with native species, predate them, bring disease and modify natural habitats

Overexploitation + Affects

-The hunting of organisms by humans at a rate faster than they can reproduce, leading to decreased population sizes.

-Less food availability to predators, affecting food chain

Consequences of fertilisers pollution

-Residue in soil can interrupt nutrient cycles

-Can run off into waters and cause eutrophication:

A process where fertilizer runoff causes algal blooms, blocking light for aquatic plants and leading to oxygen depletion by decomposers. Organisms can no longer respire, leading to biodiversity loss

Process of plastic in water

-Toxins in plastics can affect hormones and other bodily functions

Biomagnification: Toxins from microplastics or other pollutants increase in concentration as they move up the food chain to predators.

Air pollution + climate change

-Carbone dioxide and methane can create greenhouse affect

-A 'blanket effect' where solar heat warms the surface of the earth but is trapped by gases and cannot escape.

-Remains in atmosphere for a long time and can disrupt ozone layer

-Consensus suggests there’s a positive correlation with global warming and greenhouse gas emissions, supporting the statement that it is human induced

Affects of global warming

-Melting glaciers → Higher sea levels + less habitat

-Unpredictable weather patterns → Flooding → Less habitat

-Organisms have to adapt, migrate, or go extinct

Examples of organisms adapting, migrating, or going extinct in response to climate change induced selection pressures

-Star Mountainous coral has adapted to the heat that causes coral bleaching

-Birds/dragonflies have migrated Northward to relocate: Can cause competition with native species and disadvantage for its stationary predators

-Bramble Cray Melomy has went extinct due to rising water levels

-Benefits bores as heat allows young/older ones to survive and grow oak trees

Past Environment: Rock formations

-Alfred Wegner suggested the continents were once one large landmass Pangea

-He supported his theory through the continents looking like a jigsaw puzzle, fossil distribution, mountain/rock formations and paleoclimate data

-Magma rises, cools and solidifies at ocean ridges to create crust for new sea floor

-This drags the continents

Aboriginal Rock paintings

-Thousands-of-years-old artworks that record changes to Australia’s past climate and species, such as depictions of the Thylacine and Tasmanian devil.

-Can show changes in distribution, allowing us to interpret the rile of climate change

-Can depict most abundant organisms in an area at a time and its drawn features allow us to interpret environmental factors that acted as selection pressures that resulted in its evolution

Ice core Drilling

-The process of extracting cylinders of ice from glaciers which preserve information like pollen, microbes, dust, and air.

-Can be found as frozen water, dissolved impurities in snow and air bubbles

-Air bubbles can be analysed through gas analysis to infer past atmospheric conditions

Stromatolites

Structures that preserve biological activity as rock, reflecting consistent interactions between life and the environment.

Species distribution model (SDM)

A model using field data and environmental variables to identify preferred conditions for survival and forecast shifts in response to climate change.

Fossils + Radiometric dating

Fossils: Remains, impressions, or traces of life forms preserved in a material

-Requires quick burial, anoxic environment and minimal disturbance

-Radiometric dating allows us to find its specific ago to determine how long ago areas had a specific environment