paper 2 ess Flashcards
(22 cards)
Outline how the ABUNDANCE of a MOTILE species in an ecosystem can be MEASURED
the abundance of a motile species in an ecosystem can be measured through the Lincoln Method.
(1) CAPTURE a sample of individuals from a population
(2) MARK each individual in a HARMLESS, RECOGNIZABLE way
(3) RECORD the number marked
then
(4) After some TIME, take a SECOND SAMPLE from the SAME population
(5) COUNT the TOTAL number of individuals captured
(6) COUNT how many of these are MARKED from the first sample
(7) use formula to estimate population size
Explain ONE natural and ONE human-caused factor that influences CHANGES in BIODIVERSITY
natural one - EXTINCTION:
mass extinctions of the past caused by various natural factors have (temporarily) REDUCED biodiversity:
ex: tectonic plate activity, climate changes (like drought) and meteorite impacts
human-caused one - CONSERVATION
conservation of ecosystems has led to INCREASED biodiversity:
ex: establishment of National Parks, ex situ conservation like zoos and legislation for protecting endangered species like CITES
Discuss the EFFECTIVENESS of habitat-based conservation in relation to the impacts of climate change
STRENGTHS :
1. Protected habitats help nature recover from climate disasters:
Healthy ecosystems bounce back more easily from floods, fires, and droughts caused by climate change when they are well-conserved.
- Conservation areas give species space to move as the climate changes:
By protecting and connecting natural areas, animals and plants can shift to cooler or safer places as their environment changes. - Conserved ecosystems absorb carbon and slow climate change:
Forests, wetlands, and oceans store large amounts of carbon, helping reduce the greenhouse gases that cause global warming.
LIMITATIONS:
1. Climate change can damage even protected habitats:
Rising temperatures, sea levels, and extreme weather can harm conserved areas, making them less effective over time.
- Fixed conservation zones may not match where species need to go:
As climates shift, species may need to move outside protected areas, but many conservation plans don’t account for that. - Climate stress increases pressure on protected habitats:
When climate change affects people’s resources (like food or water), they may turn to nearby natural areas, threatening conservation efforts.
Outline TWO transfers and TWO transformations within a soil system
transfers:
(1) UPTAKE of nutriennts by plants
(2) SOIL EROSION by wind
transformations:
(1) DECOMPOSITION of organic matter
(2) RESPIRATION of living organisms
COMPARE and CONTRAST the pathways of energy through the atmosphere and the pathways of energy through an ecosystem
IN BOTH (compare):
(1) energy is NOT created or destroyed
(2) the SOURCE of energy is the SUN
(3) energy is LOST as radiated HEAT
CONTRAST:
(1) in the ATMOSPHERE, energy from the sun is reflected by CLOUDS, whereas, in the ecosystem it is reflected by ICE
(2) the energy from the SUN is used in photosynthesis by plants ONLY in ECOSYSTEMS
(3) Transfers & transformations in ecosystems often go through living organisms, but not in the atmosphere
Explain how the movement of tectonic plates has influenced biodiversity and evolution.
(1) plate movement creates and seperates land masses
(2) isolation leads to new species
(3) new habitats and climates like mountains and islands form
(4) ocean currents and climate patterns shift
(5) tectonic activity causes volcanic erruptions that may trigger mass extinctions
(5) these isolates and diverse environments lead to the formation of biodiversity hotspots
Outline the transfers and transformations of matter as it enters and flows through the first trophic level of a food chain.
transfers of matter:
- CO2
- Water
- minerals/nutrients
transformations of matter:
- photosynthesis
- inorganic matter (ex: CO2) transformed into organic matter (ex: glucose)
- minerals build proteins, DNA, etc
A new parasite is introduced into an ecosystem and manages to infect a host species. Outline how the host and parasite species may reach an equilibrium over time.
(1) as the parasite infects the host species, the host population starts to decline
(2) as the number of hosts decreases, it becomes harder for the parasite to spread to new individuals
(3) hosts with natural resistance are more likely to survive and reproduce, passing on their resistant traits
(4) parasites that don’t kill their hosts quickly have better chances of spreading, so the less deadly efforts become more common
(5) over time, both populations adjust: the host becomes more resistance, and the parasite becomes less harmful
(6) hence, equilibrium is reached as they learn to coexist without either being wiped out
parasite spreads - number of hosts decreases - parasites are left with limited hosts - hosts that have natural resistance survive - such hosts pass down their favourable features to their offspring - population with high natural resistance increase - parasites that do not kill their host quickly have better chances of spreading - leads to an equilibrium as both adjust and learn to coexist without wiping each other out
Explain how tectonic plate activity may lead to the formation of new species
(1) volcanic activity may give rise to new habitats (ex: mountains/islands)
(2) populations may get divided by geographical barriers
(3) different parts of the population may find themselves in new habitats
(4) there may be a variety of diverse traits in the population
(4) some features may be more fir for this new habitat
(5) individuals with these adaptive trails will be more likely to survive
(6) these survivors will pass the adaptive features on to their offspring
(7) over time, further adaptations may give rise to a population that is unable to interbreed with original species
(8) once the populations are unable to interbreed, a new species is formed
Justify the role of different EVSs in deciding between in situ and ex situ conservation strategies.
Ecocentrics: IN SITU conservation
- believes that species should be protected WITHIN their NATURAL ECOSYSTEMS, where ecological relationship are maintained
- supports national parks, reserves because it keeps species in their ORIGINAL context and PROMOTES NATURAL EVOLUTION and ecosystem function
- may see EX SITU as LAST RESORT
Anthropocentrics: BALANCES IN SITU & EX SITU:
- focuses on CONSERVING species for the BENEFIT of humans (ex: for tourism, food, etc)
- may support IN SITU for PRESERVING ecosystems to BENEFIT humans, but also seek EX SITU if it helps recover endangered species or ensure food security
Technocentrics: more accepting of EX SITU:
- believes in using TECHNOLOGY and SCIENCE to PROTECT species, even OUTSIDE their natural habitats
- favors captive breeding, seed banks, cloning and advanced genetic tools
- may view the natural ecosystems as REPLACABLE or MANAGEBAL through INNOVATION
Outline four ways in which changes in the population of one species may reduce the carrying capacity of an environment for another species.
(1) MORE COMPETITION - when a larger population uses more food & water, it leaves less for other species
(2) HABITAT DAMAGE - one species might destroy or change the habitat, making it harder for others to survive
(3) MORE PREDATORS - if predator numbers grow, they may hunt more of another species, lowering its population
(4) DISEASE SPREAD - dense population can spread disease, which can infect and harm other species too
Explain how natural processes can lead to the formation of new species
new species can form through SPECIATION which happens NATURALLY over time:
(1) ISOLATION ( a population gets split into two groups ex: by a mountain)
(2) DIFFERENT ENVIRONMENTS (each group lives in a different environment with different conditions)
(3) GENETIC CHANGES (mutations and natural selection cause the groups to change over generations)
(4) REPRODUCTIVE BARRIER (eventually, groups become so different they can no longer mate and produce fertile offspring, which means they are considered SEPERATE SPECIES)
Describe BIOTIC and ABIOTIC factors with reference to a named ecosystem
ex: SAVANNAH
BIOTIC factors are LIVING factors:
ex: predators (lions), herbivores (zebras), producers (cacti), decomposers (fungi)
ABIOTIC factors are NONLIVING PHYSICAL factors.
ex: sunlight, temperature (hot), rainfall (seasonal droughts and rain) and soil type
With reference to named societies, to what extent do EVSs influence the use of resources?
AMAZON TRIBES (indigenous)
Ecocentric : they use resources CAREFULLY, hunting and farming in ways that maintain ecosystem BALANCE
Industrial + Trade societieies (ex: CHINA)
Technocentric/Anthropocentric: focus on ECONOMIC GROWTH and TECHNOLOGY to solve problems. INTENSIVE use of resources like fossil fuels - OVEREXPLOITATION
Identify FOUR ways to ensure reliability of the mark-release recapture method in estimating population size.
(1) Mark ENOUGH individuals to get a representative sample of the population
(2) marks should be VISIBLE but NOT harmful
(3) give enough TIME for marked individuals to mix EVENLY back into the population
(4) conduct MULTIPLE recapture sessions to CONFIRM consistent results
Explain how the interactions between a species and its environment give rise to the S shape of its population growth curve
(1) LAG PHASE - at first, population is SMALL, so growth is SLOW because individuals are few and REPRODUCTION is just STARTING
(2) EXPONENTIAL PHASE - with PLENTY of resources and LIMITED competition, population GROWS RAPIDLY
(3) DECELERATION PHASE: AS the population grows, RESOURCES like good and space become LIMITED. COMPETITION increases, SLOWING GROWTH
(4) STABLE PHASE: the population size levels off when the environment can NO LONGER suppoer more individuals - CARRYING CAPACITY - birth rates=dead rates
Outline the factors that contribute to total biodiversity of an ecosystem
(1) species RICHNESS
(2) species EVENESS
(3) GENETIC diversity
(4) HABITAT diversity
Explain how ecological techniques can be used to study the effects of human activities on biodiversity of a named ecosystem
RAINFOREST:
(1) Quadrat Sampling - counting tree species in logged vs untouched forest areas to MEASURE LOSS of plant diversity
(2) Transect Lines - recording ANIMAL SIGHTINGS along trails near deforestated zones to TRACK CHANGES in wildlife distribution
(3) Remote Sensing - using SATELLITES to monitor rates of deforestation caused by farming and mining
(4) MARK - RECAPTURE: tagging jaguars to estimate population decline
(5) Biodiversity Indices: CALCULATING species diversity before and after disturbance
Explain both positive and negative feedback mechanisms that may play a role in producing a typical S population growth curve for a species
Negative feedback is the main feedback mechanism controlling the population as it approaches carrying capacity.
Example: Increased population density → more competition → lower birth rates/higher death rates → population growth slows.
This negative feedback stabilizes population size around carrying capacity.
Positive feedback is less obvious in logistic growth but can occur at very low population sizes:
Example: Small population → fewer mates → lower reproduction → population growth slows further (called the Allee effect).
Or, when population is growing, reproduction rates increase with population size, temporarily accelerating growth (though this is more a density-dependent effect than classic positive feedback).
So:
The S-shaped curve is mainly shaped by negative feedback that limits growth near carrying capacity.
Positive feedback mechanisms are generally weak or absent in typical logistic growth, but can occur in some cases like the Allee effect.
Would you like me to explain the Allee effect or give examples of these feedbacks?
Why the ecological capacity of two populations consuming the same quantity of food and energy may be different?
Types of food consumed: One population may eat more resource-intensive foods (like meat), which require more land and water to produce.
Efficiency of resource use: Differences in technology and infrastructure affect how efficiently resources are used (e.g., energy-efficient appliances vs. wasteful ones).
Waste and recycling: One population may waste less and recycle more, reducing their overall footprint.
Land use practices: How land is managed (intensive farming vs. sustainable agriculture) impacts the footprint size.
