REN1201 Flashcards
Exam!
How is environmental science defined?
Systematic study of the natural and human-made world
What does the word ‘environment’ refer to?
An organism’s surroundings
What are the 4 components of the biophysical earth system?
Atmosphere, Lithosphere, Hydrosphere, Biosphere
What is an atmosphere?
Gas surrounding the earth that protects from UV, traps IR and provides oxygen.
What is lithosphere?
Solid crust and upper part of the earths mantle, contributes to rock and soils
What is hydrosphere?
Represents 70% of earths surface covered in liquid and frozen water (sometimes known as the cryosphere).
What is biosphere?
Parts of the earth that contains living organisms and the complex interactions occurring.
What are the 4 components of the human-earth system?
Economics, Population, Politics, Ethics
What are the 2 main factors in human effect on the environment?
Consumption of resources, production of wastes and pollutants
What does ‘resources’ refer to?
Anything an organism uses up or depletes (i.e. food, water, etc.)
What is renewable energy?
That which can be consumed and replenished quickly (ie. food crops, forests, solar, etc.
What is non-renewable energy?
Materials that exist in finite amounts and can’t be replenished within a reasonable time frame.
What is waste assimilation?
The ability of the environment to absorb wastes.
What does PCB stand for?
Polychlorinated Biphenyls
What did the early ‘doomsday’ scenarios (in the 70s) suggest?
That there were limits to human population growth.
What did the Millennium Ecosystem Assessment Report reveal?
- 60% of ecosystem services that support life are being degraded.
- Human activity is changing the world around us, leading to mass extinction.
- Relieving poverty wont succeed while environmental degradation is set to worsen.
What is the scientific method?
The systematic approach of observation, hypothesis formation, hypothesis testing and hypothesis evaluation.
What is a hypothesis?
A tentative explanation for an observation or question.
What is a theory?
A hypothesis thats been repeatedly tested with little modification.
TRUE OR FALSE: Scientific method = Hypothesis > Analysis > Experiment > Conclusion
False
TRUE OR FALSE: Scientific method = Hypothesis > Experiment > Analysis > Conclusion
True
How does ‘logical positivsm’ view the natural world?
In terms of cause and effect relationships.
What is a biotic component?
It includes neighbouring individuals of the same or different species and their interactions (parasitism, symbiotic relationships, competition, etc.).
What is an abiotic component?
A wide range of factors that chiefly derive from basic physical and chemical interactions (ie. weather, climate, radiation, etc.).
What is matter?
Anything that takes up space and has mass (and has 3 interchangeable forms: liquid, solid and gas).
What are elements?
Simplest substances that can be isolated chemically (is periodic table) [consists of atoms].
What are atoms?
Smallest units of matter capable of entering into chemical reactions (consists of neutrons, electrons, protons).
What is a molecule?
Conjunction of atoms of the same element (i.e. N2, O2, etc.)
What is a compound?
A molecule containing different kinds of atoms (i.e CH4, CO2, etc.)
Organic compounds form the basis of all life. What are the four major categories of them?
Carbohydrates, lipids, proteins, nucleic acid.
How can energy be defined?
The ability to do work; can be heat, light, electrical and chemical.
What is kinetic energy?
Energy in moving objects.
What is potential energy?
Stored energy.
What is chemical energy?
Energy contained in chemical bonds
What is the First Law of Thermodynamics?
Energy can be neither created nor destroyed.
What is the Second Law of Thermodynamics?
In every energy transformation, potential energy is reduced because heat energy is lost in the process.
How old is the Universe?
10-20 billion years old.
How long ago were the basic chemicals necessary for life on earth present?
4.6 billlion years ago.
How long ago did first multicelled organisms originate?
About 750 million years ago.
What is photosynthesis?
Process where plants take light energy from the sun and atmospheric CO2, and convert into chemical energy, releasing O2 as a waste product whilst retaining CH20 (sugar).
When did Hutton and Smith advance the concept of geological time through layers?
Between 1785-1800.
What is radiometric dating?
The decay of certain types of unstable atoms and isotopes.
What is the geological time scale?
The system that chronologically delineates major changes in the earths existence.
What is the longest length of time; Period, Epoch or Era?
Era
When was the Archean Super-Era (Eon)?
4500-2600 Million years ago
When was the Proterozoic Super-Era (Eon)?
2600-600 Million years ago.
When did the Phanerozoic Super-Era (Eon) begin?
570 Million years ago.
What are the 3 Eras of the Phanerozoic Super-Era, and their dates?
Paleozoic (570 - 245mya) [Cambrian, Ordovician, Silurian, Devonian, Carboniferous & Permian Periods)
Mesozoic (245 - 66mya) [Triassic, Jurassic & Cretaceous Periods]
Cenozoic (66mya - present) [Paleogene, Neogene & Quaternary Periods].
What distinct patterns are revealed by the fossil record?
i) Organisms appear sequentially.
ii) More modern fossils more closely resemble living species today.
iii) Extinction is eventual fate of all species.
When did the first prokaryotic (single ‘pre’-celled) organisms appear?
Approx 3.8 billion years ago.
When was the rise of the dinosaurs?
Approx 252 million years ago.
When did the first vertebrate fish appear?
Approx 505 million years ago.
When did the first mammals and birds appear?
Approx 201 million years ago.
When did the first early humans appear?
Approx 2.6 million years ago.
What is panspermia?
Some organic compounds that formed life may be derived from extraterrestrial origins.
What is the chemical origin hypothesis?
Complex organic compounds derived from organic compounds already on the earth.
T or F: Traces of life in the form of proteins and amino acids were estimated to be dated to 2 billion years ago?
False (3.8 - 3.6 billion years ago).
What is a stromatolite?
Layered mounds, columns and sheets found in rock.
What is cyanobacteria?
Procaryotic cells that lack a DNA packaging nucleus.
What is an autotroph?
Obtain energy from inorganic sources such as sunlight (via photosynthesis).
What is a heterotroph?
Obtain energy from organic sources (other organisms).
What is the simplified equation for the biochemical reaction of photosynthesis?
CO2 + H2O + solar energy —-chlorophyll—> (CH2O) {carbohydrate} + O2
What does ecology mean?
The scientific study of the interactions that determine the distribution and abundance of organisms, as well as their inter relationships and relationships with their physical and chemical environments.
What is an organism?
An individual living thing (plant, animal or single celled life form).
What is an organelle?
A sub-cellular component .
What is the terms for all the individuals of the same species?
Population.
What is the biological hierarchy of complexity within living -organisms? (hint: molecules –> organelles –> …
Molecules –> Organelles –> Cells –> Tissues –> Organs –> Organ systems –> Organism (individual).
What is the ecological hierarchy? (hint: organism (individual) –> population –> …
Organism (individual) –> Population –> Community –> Ecosystem –> Biosphere
What is the term for the location of where populations of different species interact?
The ecological community
What is an ecosystem?
A complex interacting network of organisms and environment
OR
The functional systems formed by communities and their environment.
What is the fitness of an organism?
The measure of their ability to produce viable offspring to contribute to future generations.
What does adaptation refer to?
Any heritable trait that aids survival or reproduction in a particular environment.
What is a heritable trait?
Something capable of being transmitted to the next generation.
What is the evolution of a new species from previously existing species called?
Speciation
When is an organism at its most abundant?
When conditions for growth and reproduction are at an optimum (optimum range).
What is a limiting factor?
The tolerance limits that an organism can survive at.
The position an organism fills in its environment, comprising the conditions under which it is found and th resources it utilises is known as a what?
Ecological niche.
True or False: an organisms niche includes everything that affects and it affected by the organism in its lifetime.
True
What is the term for the physical environment in which an organism is found?
Habitat.
What is the combination of biotic and abiotic components through which energy flows and materials cycle known as?
Ecosystem.
What is an open system?
A system that can exchange energy or material with other ecosystems.
What is the role of producers?
To convert energy from the environment into high-energy carbon bonds (ie. sunlight to carbohydrate through photosynthesis of plants).
What is another term for producers?
Autotrophs.
What is a consumer?
Gets its energy from the carbon bonds made by producers.
What is another word for consumer?
Heterotroph.
What is the trophic level of a herbivore?
Primary consumer
What is the trophic level of plants?
Primary producer
What is the trophic level of carnivores that eat herbivores?
Secondary consumer
What is the trophic level of carnivores that eat carnivores?
Tertiary consumer
What is a detritivore?
A decomposer that feeds off dead and decaying matter.
What is the path of food energy from the source, through herbivores and into carnivores called?
The food chain
True or false - food webs are linear models
False - food CHAINS are linear, food webs are multi dimensional
What is the role of chlorophyll?
To absorb light energy.
What is photsynthetic efficiency?
The efficiency at which light energy is captured by plants and converted to organic forms.
True or false: 25% of light that falls onto a plant is chemically absorbed via photosynthesis.
False (only about 1%).
The mass of organisms per unit area is known as:
Biomass
What is defined as the rate at which biomass is produced per unit area by primary producers?
Primary productivity
How is energy lost by an autotroph?
Respiratory heat.
The total amount of energy fixed by plant minus energy lost to radiation is called what?
Net Primary Productvity
X = energy assimilated across gut wall ÷ amount of food energy ingested.
What is X?
Assimilation efficiency
X = amount of new biomass produced ÷ assimilation efficiency
What is X?
Production efficiency
What are biogeochemical cycles?
The cycling of chemicals through biogical (biotic) and geological (abiotic) compartments.
How are nutrients released from abiotic compartments?
Through weathering, erosion and major geological perturbations.
What are the 3 major processes of the water cycle driven by solar energy?
i) Precipitation
ii) Evaporation
iii) Transpiration
What is precipitation?
When water condenses from a gaseous state in atmosphere and falls to the earth.
What is evaporation?
When liquid water becomes gas
What is transpiration?
When water is drawn into a plants roots and move to leaves where it evaporates quickly.
True or false: 75% of evaporation comes from the oceans
True
Most plants absorb nitrogen in the form of …?
Nitrate NO3 and ammonium ions (NH4)
The 3 biological conversions of nitrogen critical in the nitrogen cycle are:
i) Nitrogen fixation
ii) Nitrification
iii) Denitrification
True or false: The major reservoirs in the phosphorus cycle are in the atmosphere
False (major reservoirs are in rocks and sediments).
What is a eukaryote?
A ‘true’ cell with a membrane bound nucleus containing DNA, whose evolution gave rise to multicellularity.
What is meant by the symbiotic origin of multicellularity?
Where multicellular organisms arose from eukaryotes to form a symbiotic relationship where each individual was cooperating to form a single organism.
What is meant by the colonial origin of multicellularity?
Where many single-celled organisms produce colonies, sharing the same genetic code.
Why did life ‘explode’ in the Cambrian period, 550mya?
Oxygen levels in the earths atmosphere approached levels of today.
What is biomineralisation?
The manufacture of minerals by living organisms.
What are trilobytes and when did they appear?
Heavily armoured animals part of the earliest known group of arthropods, survived for 300m years, until the end of the Permian 250mya.
Which 3 problems did earliest plants (475mya) need to solve to live on land?
i) Dessication: adaptations to survive out of water
ii) Support: adaptations to survive gravity
iii) Reproduction: needed protection from surroundings
What is a bryophyte?
The transition between charophytic algae and vascular plants.
What was significant about the carboniferous period?
345-280mya, large tracts of swampy forests and vascular plants (such as conifers) thrived.
When was the Silurian period and why was it relevant?
440-410mya; first terrestrial arthropods appear in fossil record.
When did the earliest amphibians appear?
During the Permian period (286-245mya) - the first truly terrestrial vertebrates!
When did the earliest reptiles evolve?
280mya from early amphibians.
Which 2 changes allowed reptiles to control water loss while exploiting drier habitats?
i) The development of the amniotic egg
ii) Development of water conservation mechanisms (such as a tough skin).
Which Era, from 245-66mya, is regarded as the “Age of Reptiles”?
Mesozoic Era.
The dinosaurs died out at the end of which period, during which the earth became colder and more variable?
The Cretaceous Period.