Module 4: Ecosystem Dynamics Flashcards
Abiotic definition
physical rather than biological; not derived from living organisms.
biotic definition
relating to or resulting from living organisms
abiotic examples
- Light
- Temperature
- Water
- Shelter
- Topography
- Chemical components
biotic examples
plants, animals, algae, funghi
How do abiotic factors affect species?
Biotic factors in environment that affect a species. Influence behaviour, survival and reproduction. Organisms have certain characteristics suited for different environments -survival benefits.
Organisms less suitable for specific conditions are less likely to reproduce.
abiotic complex example:
Coral bleaching
Selection pressures: rise in sea temperature
Effect: bleached coral will die, reducing size of reef for marine.
Selection pressure
Selection pressure means factors that contribute to selection which variations will provide the individual with an increase chance of surviving over others.
effect of selection pressure:
Because of selective pressures, organisms with certain phenotypes have an advantage when it comes to survival and reproduction.
Keystone selection pressure:
when keystone spec is removed, ecosystem becomes less stable and structure changes.
Keystone selection pressure effect:
Consequences on diversity and abundance.
Acidification:
Selection pressure: Water pH
Individual effect: Affects the deposition of calcium carbonate
Possible consequence: Reduces the habitat for the algae and therefore less food for the polys
Crown of Thorns Starfish
Selection pressure: Predators
Individual effect: Affects the population of the coral Possible consequence:Reduces the amount of habitat left for the marine life as more coral is dying.
Climate change
Selection pressure: Water temperature
Individual effect: Not ideal temperatures for breeding Possible consequence: Extinction of certain animals that cannot live in warmer temperatures
Tourism
Selection pressure: Stress on the environment Individual effect: Broken coral, fuel in the water and disruption to the usual functioning of the ecosystem Possible consequence:Damage to the natural habitat
Symbiosis
living together
What are the two types of relationships between different species?
Beneficial and detrimential
mutualism example
- Mutualism - sea anemone (provides shelter and protection) and clown fish (provides nutrients)
commensalism example
- Commensalism - shark (no benefit), and remora (small fish feed on scraps of prey of sharks)
parasitism example
- Parasitism - head lice (feed on blood) and human (host)
mutualism
both organisms benefit
commensalism
one benefits, the other unharmed
predation
one organism eats another
predation example
dingo eats wallaby
parasitism
one organism lives on another obtaining food from it
competition
organism compete for limited resources
example of competition
insects for nectar
inhibition
one organism directly prevents the development of a competing organism
Consequences of predation:
• Predator numbers copy those of prey
Consequences of competition:
• If one species is more successful, then the less successful species may be driven to very low numbers or die out completely
Effects of symbiosis:
- Increased evolutionary diversification e.g. biodiversity
- Development of new species e.g. integration of genetic material and development of eukaryotic cells
- Sources of new capabilities e.g. enhancement in evolutionary fitness
Consequence of predation
Animal species kills and feeds on another, predator eats prey.
high prey compared to lower predators means that predators increase and prey decreases (because they are all eaten), causes shortage of food as the prey has all been eaten meaning that predators decrease too.
individual relationship
single organisms
population relationship
group of organisms, same species
communities relationship
ecological grouping of different species living and interacting together.
ecosystems relationship
formed by communities interacting with one another and physical surroundings.
biomes relationship
group of communities with similar structures and habitats extended over a large area.
biospheres relationships
sum of all ecosystems on earth.
habitats
where an organism lives.
microhabitats
smaller area within habitat (tree canopy) where organisms experiences different environments compared to overall habitat (temp, humidity, sunlight)
Niches
the specific way in which an organism fits into its community or ecosystem, including its actual habitat, use of resources and its abiotic and biotic interactions.
Intraspecific competition
between species
interspecific competition
within a species
How do you measure population through sampling techniques?
quadrants, transects, tagging and capture-recapture
quadrants
throw quadrat randomly into an area and count the population of a certain species. Used for counting small plants or slow moving, small animals.
transects
to determine variation within the population. Used to count larger plants.
Tagging/capture-recapture:
to recognise the animals that have already been counted. Use to count animals that move and are hard to identify.
What are adaptations?
characteristics that increase the survival and reproductive chances of an organism in its environment. They are not a change that an organism makes in response to the environment but usually begin as variations.
structural adaptations
things you can see, body shape, anatomical features that assists an organism to adapt to abiotic or biotic environment e.g. large ears, sunken stomata, flying fish body shape
behavioural adaptation
actions that an organism takes to improve survival e.g. seeking shade or shelter, migration
Physiological adaptation:
inner body functions e.g. production of concentrated urine, venom, shivering to maintain body temperature, antifreeze in arctic plants
Paleontology -
the scientific study of fossils and all aspects of extinct life
geology
the scientific study of the origin, history and structure of the Earth as recorded in rocks
Fossils:
- Law of superposition, fossils in different layers relate to age
- Darwin’s Theory of Evolution by natural selection
Aboriginal rock art:
- Depicts flora and fauna of the past
* e.g. thylacine, droughts
Geological evidence:
- Changes from anaerobic to aerobic atmosphere
* Shown in banded iron
Microfossils
- Earlier fossils
* e.g. single celled, filamentous anaerobic prokaryotes (didn’t have a nucleus, and didn’t require oxygen)
Why do scientists continue to make theories?
Scientists continue to develop theories about how life has changed on Earth. Changes in abiotic and biotic factors have left traces of evidence behind. Scientists study this evidence, make inferences and reconstruct past ecosystems.
What is a niche comprised of?
The habitat in which an organism lives
The activity patterns of the organism (e.g. periods of time during which it is active)
The resources it obtains from the environment (e.g. food sources, territorial boundaries, etc.)
The interactions that occur with other species in the community (e.g. predator prey relationships, competition, etc.)
Understanding: Niches and species
Two species cannot survive indefinitely in the same habitat if their niches are identical
If two distinct species share an identical niche, there will be interspecific competition for available space and resources
competitive exclusion
one species uses resources more efficiently and drives out another species to extinction
resource partitioning
species alter their use of niche and divide resources
