IB DP Biology HL D4.2 Stability and change Flashcards

[q] Ecosystem stability

[a] ability of an ecosystem to maintain its structure and function over long periods of time and despite disturbances

[q] Factors affecting stability of ecosystems

[a] Supply of energy; recycling of nutrients; biodiversity; climatic factors

[q] Supply of energy

[a] The sun is the ultimate source of energy for the processes on Earth.

A stable ecosystem requires a balanced energy flow to ensure that no one species becomes too dominant or too scarce.

[q] Recycling of nutrients

[a] Transferring energy from the environment to the organisms that populate it and back to the environment again

[q] Biodiversity

[a] Includes species diversity, habitat diversity, and genetic diversity. 

Highly diverse ecosystem is more likely to be stable because it can better resist disturbances.

[q] Climatic factors

[a] Physical factors such as climate, topography, and water availability.

[q] Tipping point

[a] The critical threshold of a change that results in a significant and often irreversible change in an ecosystem’s structure, function or composition.

[q] Resistance

[a] the ability of an ecosystem to withstand or to resist change

[q] Resilience

[a] the ability of an ecosystem to recover from disturbances

[q] Population

[a] a group of organisms of the same species that occupy a given area

[q] Species

[a] A group of similar organisms that can breed and produce fertile offspring.

[q] Community

[a] Population that share similar characteristics and inhabit the same habitat, can be members of the same species, but do not have to be

[q] Autotroph/Producer

[a] an organism that is able to form nutritional organic substances from simple inorganic substances

[q] Heterotroph/Consumer

[a] organism that obtains food by consuming other living things

[q] Niche

[a] An organism’s particular role in an ecosystem, or how it makes its living.

[q] Percent change formula

[a] % change = (final value – initial value / initial value ) × 100

Negative – decrease

Positive – increase

[q] Mesocosms

[a] biological systems that contain the abiotic and biotic features of an ecosystem but are restricted in size and/or under controlled conditions.

Used in ecological research to allow scientists to investigate a variety of issues.

[q] Keystone species

[a] A species on which other species in an ecosystem largely depend on.

If it were removed the ecosystem would change drastically.

[q] Trophic cascade

[a] If the keystone species declines or is removed, it can disrupt the balance within the food web, leading to unchecked growth or decline in certain species.

This disruption can have far-reaching effects, altering species interactions and potentially destabilizing the entire ecosystem.

[q] Habitat modification (impacted by keystone species)

[a] Keystone species can shape and modify the physical structure of their habitat.

If the keystone species is lost, the habitat modifications they provide may also disappear, affecting the availability of resources and shelter for other organisms.

[q] Nutrient cycling and ecosystem processes (impacted by keystone species)

[a] If keystone species’ populations decline, these important ecological processes may be disrupted, leading to imbalances in nutrient availability and biogeochemical cycles.

[q] Yellowstone wolves

[a] Example of keystone species and its impact in it’s ecosystem. Wolves were removed from Yellowstone in the 20th century, conditions in the park declined drastically.

Reintroduced in 1995 to increase biodiversity

Biodiversity

Biological variety of genes, species and ecosystems

[q] Overexploitation

[a] Practice of harvesting or hunting to such a degree that remaining individuals may not be able to replenish the population

[q] sustainable harvesting

[a] Using natural resources at a rate where nature can replenish them.

[q] Sustainability

[a] The capacity of meeting the needs of the present generation without compromising the ability of future generations

[q] Sustainability in agriculture

[a] the practice of cultivating and producing agricultural products in a manner that preserves and enhances the long-term environmental, social and economic well-being of farming systems.

[q] Soil erosion

[a] May be caused by excessive tillage, removal of vegetation, excessive grazing by livestock, and mono-cropping.

A process that involves the detachment, movement and transportation of soil particles from one location to another.

Loss of soil nutrients and therefore fertile land.

[q] Agrochemicals

[a] Artificial pesticides and fertilizers that are used in farming.

Can impact soil pH, causing acidic soils as well as increase soil erosion.

Possible side-effects to human health.

[q] Water use

[a] Excessive watering can lead to leaching of nutrients beyond the crop zone.

Improper management of runoff can lead to water scarcity and pollution. Over-extraction of groundwater can deplete aquifers.

Excessive use of fertilizers and pesticides can contaminate water bodies, harming aquatic ecosystems and human health, and may also harm birds and other wildlife.

[q] Biodiversity

[a] Mono-cropping and genetic homogeneity make agricultural systems more vulnerable to pests diseases and climate change impacts.

Deforestation and land conversion contributes to habitat loss, decline in biodiversity, and disruption of ecosystem services.

[q] Carbon footprint

[a] Fertilization, tilling, livestock farming, transportation, and food processing produce and emit greenhouse gas.

Primarily consists of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).

[q] Eutrophication

[a] A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae or cyanobacteria.

[q] DDT

[a] dichloro-diphenyl-trichloroethane. An insecticide that is also toxic to animals and humans

[q] Bioaccumulation

[a] An increased concentration of a chemical within an individual organism over time.

[q] Biomagnification

[a] The increase in chemical concentration in animal tissues as the chemical moves up the food chain.

[q] Effects of microplastics and microplastics pollution of the oceans

[a] Disruption of marine food webs, chemical pollution, wildlife entanglement and ingestion, habitat degradation

[q] Mircoplastics

[a] small plastic particles or fragments that measure less than 5mm in size.

They can either be intentionally manufactured as small plastic beads used in personal care products or can result from the breakdown of larger plastic items over time.

[q] Macroplastics

[a] Larger pieces of plastic debris that causes problems for large fish and seabirds through ingestion and even strangulation.

These can include items such as plastic bottles, bags, fishing nets and other discarded consumer products.

[q] Rewilding

[a] reintroducing animals that have been driven out or gone extinct in an ecosystem

Species reintroduction; habitat restoration; rewilding urban areas; rewilding rivers and waterways; ecological management and natural processes

[q] What is a stable ecosystem?

[a] The capacity of an ecosystem to remain in a state of equilibrium or withstand disturbances without undergoing significant changes.

[q] Factors affecting stability of ecosystems

[a] An ecosystem requires both resistance and resilience to maintain its stability over time.

[q] Resistance

[a] The ability of an ecosystem to withstand or resist changes caused by disturbances without undergoing significant shifts in structure or function.

[q] Resilience

[a] The ability of an ecosystem to resist or recover from disturbances and maintain its structure and functions.

[q] Examples of stable ecosystems

[a] – Tropical rainforests

– Coral reefs

– Boreal forests

– Sonoran Desert

– The Daintree Rainforest

– The Borneo Lowland Rainforest

– The Namib desert

[q] What are the 4 main factors affecting the stability of ecosystems?

[a] – Supply of energy

– Recycling of nutrients

– Biodiversity

– Climatic factors

[q] Supply of energy

[a] – Energy is needed for all life processes without it ecosystems would collapse.

– The sun is the main source of energy but is inaccessible to some organisms

– Producers/autotrophs transform solar energy to produce food

– Consumers/heterotrophs use plants or other consumers to obtain energy.

[q] Recycling of nutrients

[a] – Process by which nutrients are cycled between the environment and organisms

– By efficiently recycling nutrients ecosystems can maintain nutrient availability which supports the productivity of populations and helps maintain ecosystem diversity

– Depletion of nutrients can disrupt the functioning stability of ecosystems

– Recycling prevents loss of nutrients through leaching or runoff

[q] Biodiversity

[a] – The variety of life in the world or in a particular habitat or ecosystem

– High diversity = more stable ecosystem (better equipped to resist disturbances)

– Biodiversity can be identified in different forms, including species diversity, habitat diversity and genetic diversity

[q] Climatic factors

[a] – Physical factors like climate, topography, and water availability have a high influence on stability

– Ecosystems that experience extreme physical changes/extreme weather events are less likely to be stable

– Climate conditions shape stability and determine the geographical distribution of species and the composition of an ecosystem

– Different species have specific climate requirements and tolerances

– Changes in climate conditions leads to shifts in species ranges and alters ecosystem composition

– If conditions become unsuitable for certain species balance is disrupted

[q] Tipping points

[a] A critical threshold of a change that results in a significant and irreversible change in an ecosystem structure, function, or composition.

Once a tipping point is reached ecosystems undergo transformation leading to a loss of biodiversity and a collapse of populations.

[q] How do tipping points occur?

[a] When there is a dramatic change in the ecological state away from stability.

Represents points beyond which irreversible change and damage occurs

[q] Example of tipping point

[a] Deforestation of the Amazon rainforest is a well-known example of a possible tipping point in ecosystem stability.

[q] Deforestation

[a] Deforestation is the permanent removal or clearing of forests or wooded areas, usually to convert land for agricultural, industrial or urban purposes.

[q] Use of models

[a] – To simplify complex systems and phenomena

– To better understandings

– Make predictions

[q] Mesocosms

[a] – A closed experimental system that examines the natural environment or part of the environment under controlled conditions.

– Allows scientists to create conditions mimicking possible results of climate change and see how a change in nutrient levels affects an ecosystem or investigate pollutants spread in a food web

– Factors to investigate: Ph of water, temp, sunlight, the color of light, a population size of producers/consumers

[q] Role of keystone species

[a] Species that have a disproportionately large impact on the community compared to their abundance or biomass.

Their presence or absence deeply affects the stability of an ecosystem.

Organism that helps define an entire ecosystem

[q] Trophic cascades

[a] The effects on subsequent (higher or lower) trophic levels after the elimination or reduction in numbers of individuals in one trophic level.

If a keystone species declined or got removed it can disrupt the balance within the food web leading to other species being impacted.

[q] Habitat modification

[a] Keystone species can shape and modify the physical structure of their habitat.

ex: beavers create dams that alter water flow creating new habitats for other species.

If this species disappears their habitat modifications can also be lost which affects the availability of resources and shelter for other organisms.

[q] Nutrient cycling and ecosystem processes

[a] Keystone species influence nutrient cycling and other key ecosystem processes.

If their population declines those ecological processes can be disrupted leading to an imbalance

[q] Requirements for sustainable ecosystem

[a] – Nutrient availability

– Detoxification of waste products

– Energy availability

[q] Sustainable harvesting

[a] Sustainable harvesting considers the stability of ecosystems as its primary goal.

But if the harvesting rate becomes higher than their renewing rate ecosystems may become unstable.

Assessing the sustainability of harvesting activities from ecosystems is crucial to ensure the long-term viability of renewable resources.

[q] Over exploitation

[a] Overexploiting a species means removing and using up individuals at a rate that exceeds the species’ maximum rate of reproduction e.x. overfishing

[q] Sustainability

[a] Refers to capacity of meeting the needs of present populations with out compromising the ability of future generations

[q] Sustainability in agriculture

[a] The practice of cultivating and producing agricultural products in a manner that preserves and enhances long term environmental, social, and economic well being.

[q] Factors affecting sustainability of agriculture

[a] Soil erosion

Agrochemicals

Water use

Biodiversity

Carbon footprint

[q] Soil erosion

[a] Processes involving detachment, movement, and transport of soil from one area to another.

Natural phenomena that is being accelerated by human activity.

[q] Agrochemicals

[a] Includes synthetic fertilizers and pesticides that have effects on soil degradation and erosion.

Some fertilizers contribute to soil acidification reducing pH levels.

Synthetic fertilizers lead to a decrease in soil organic matter and decrease soils ability to hold water nutrients.

[q] Water use

[a] Inefficient water use and improper management of runoff lead to water scarcity and pollution.

Over-extraction of groundwater leads to depleted aquifers.

Improperly managed irrigation and excessive water use can lead to the leaching of nutrients beyond the crop zone (water-soluble nutrients can be taken away).

[q] Biodiversity

[a] Intensive agricultural practices often prioritize high-yielding crops and livestock breeding which leads to a loss of biodiversity.

Monocropping and genetic homogeneity make agriculture systems more vulnerable to pesticides and climate change.

Deforestation and land conversions contribute to habitat loss and decreased biodiversity and disrupt ecosystem services.

[q] Carbon footprint

[a] During agricultural activities (tilling, fertilizing, livestock farming, transport) greenhouse gas is produced and emitted. Mainly carbon dioxide, methane, and nitrous oxide.

Agriculture is a contributor and victim to climate change.

The climate footprint of agriculture leads to increased concentrations of greenhouse gasses in the atmosphere.

[q] Eutrophication

[a] Eutrophication is the process by which water bodies become enriched with excessive nutrients, particularly nitrogen and phosphorus, leading to an overgrowth of algae and other aquatic plants.

This excessive growth can disrupt the balance of the ecosystem and have detrimental effects on water quality, aquatic life, and overall ecosystem health.

[q] DDT

[a] (dichloro-diphenyl-trichloroethane) was a modern synthetic insecticide produced and used in the 1940s.

It was initially used against the organisms of malaria, typhus, and other insect-borne human diseases.

It was also effective for insect control in agriculture. DDT was thought to be harmless, or the harmful effects were ignored.

However, data on DDT’s negative effects on insects, birds, and fish started accumulating.

[q] Bioaccumulation

[a] The process by which certain substances (toxins/pollutants) accumulate and increase in concentration within the tissue of organisms over time.

When pollutants enter ecosystems organisms can receive them through absorption, ingestion, or contact.

These chemicals can be persistent and resist breakdown causing them to accumulate.

[q] Biomagnification

[a]Accumulation of pollutants at successive levels of the food chain.

As organisms consume other organisms the accumulated substances become more concentrated.

Consumption of contaminated organisms by predators results in transfer and accumulation of pollutants at higher trophic level.

[q] Plastic

[a] Synthetic products made from a variety of organic compounds.

Persistent and non-biodegradable.

Accumulates in soil and water.

[q] Microplastics

[a] Small plastic particles that can be made intentionally or as a result of breakdown.

[q] Macroplastics

[a] Large pieces of plastic debrise.

[q] How does plastic get into ocean?

[a] Improper waste disposal, direct littering and dumping, runoff, spills and marine debris from fishing and shipping.

[q] Disruption of marine food webs from plastic

[a] Small marine organisms filter feed on microplastics, then it is consumed by larger organisms leading to the transfer of plastics through the food chain.

This has cascading effects on reproductive success, growth, and species survival.

[q] Chemical pollution from plastic

[a] Plastics absorb and release harmful chemicals.

When organisms consume plastic they are exposed to toxic chemicals.

Micro plastics can act as carriers transporting pollutants to new locations.

[q] Wildlife entanglement from plastic

[a] Marine animals often eat plastic debris or become entangled in it.

Plastic items like fishing nets, ropes, and 6-pack rings can entangle animals causing injury or death.

Eating plastic can lead to internal injuries, blockages in the digestive system, and starvation.

[q] Habitat degradation from plastic

[a] As plastic accumulates it damages habitats and hinders the ability to provide food and shelter.

The presence of plastic alters light and nutrient dynamics in water.

[q] Rewilding 

[a] Approach to conservation and ecosystem restoration that involves reintroducing and restoring natural processes and biodiversity to ecosystems that have been degraded and altered by people.

[q] Species reintroduction

[a] Process of releasing captive animals into a habitat where their local population has dwindled.

[q] Habitat restoration

[a] Actions like reforesting, removing invasive species, restoring wetlands.

Aimed at providing suitable conditions for native species to thrive.

[q] Rewilding urban areas

[a] Focuses on reintroducing nature into urban environments.

[q] Rewilding rivers and waterways

[a] Restoring natural processes in rivers and water ways by removing barriers like dams or weirs and restoring meanders.

[x] Exit text