Environmental Disturbances

Environmental DisturbancesAn environmental disturbance is an event with the potential to harm the environment. What is an Environmental Disturbance?

Types of DisturbancesThere are two main types of Environmental Disturbances:Natural and AnthropogenicNatural- naturally occurring disturbances.

Anthropogenic- disturbances caused by human action.

Natural disturbances: hurricanes, fire, drought, flooding, changes in temperature, predation.

Anthropogenic disturbances: deforestation, mining, over fishing, air and water pollution.Can you mention different examples of Environmental Disturbances?

Effect of DisturbancesShort term effect- the ecosystem immediate reaction to the disturbance.

Long term effect- will depend on the ecosystem response and recovery to the disturbance.

How to Protect ResourcesConservation- efficient utilization of natural resources like fossil fuels, forest and water; avoiding depletion of natural ecosystem diversity and destruction of the environment.

Preservation- resources are not exploited because there are not being used.

It depends. There are some species that live in sensitive ecosystems and in order to maintain those species alive its better to leave the ecosystem untouched. However, we depend on natural resources for our daily living, in this case conservation is a better option.What is better Conservation or Preservation of the Environment?

Succession

Primary SuccessionThe establishment and development of an ecosystem in an area that was previously uninhabited

Surtsey: A Case StudyThe island of Surtsey formed by volcanic eruption off of the coast of Iceland during the period from 1963 - 1967

Surtsey Post Eruption

Surtsey Today

Secondary SuccessionThe recovery of a damaged ecosystem in an area where the soil was left intactFireweedSequoia seedling

Case Study: Yellowstone National Park1988 Devastating forest fires burn much of Yellowstone National Park.Photo: National Parks Service

Yellowstone National Park1988 Park mapshowing areas (1.6 million acres)burned by theseries of fires.

Yellowstone National Park1988 fires The immediate aftermath.Photo: National Parks Service

Yellowstone National ParkOne year after the firesNote the appearance of fireweedPhoto: National Parks Service

Yellowstone National ParkTen years after the fires (1998) Photo: National Parks Service

Yellowstone National ParkTwenty years after the fires (2008)

Case Study - ChernobylIn April, 1986, a nuclear power plant in the former USSR experienced a core meltdown and a catastrophic release of radioactivity into the environment.

ChernobylSurrounding towns and villages had to be immediately, permanently abandoned.

Chernobyl Twenty Years Later

Chernobyl Twenty Years LaterPripyat town square.

Chernobyl Twenty Years LaterPripyat Soccer Stadium opened in 1986.

Chernobyl Twenty Years LaterA local highway.

Energy in EcosystemsFood Chains, Food Webs and Energy PyramidsCourtesy: www.lab-initio.com

Producers (Autotrophs)Photosynthetic organismsCapture energy from sunlight, CO2 and H2OMost producers are photosyntheticChemosynthetic organismsCapture energy from chemical compounds in the surroundings

Consumers (Heterotrophs)HerbivoresEat only plants and fungiOmnivoresEat both plants/fungi and animalsCarnivoresEat only animalsDetrivoresEat dead organic matterDecomposersBreak down organic matter into simpler compounds

Biotic Energy MovementProducersAutotrophs (Photosynthesizers, Chemosynthetic organisms)Primary consumersHerbivores and omnivores that eat producersSecondary consumersCarnivores and omnivores that eat herbivoresTertiary consumersCarnivore eats another carnivoreDecomposers and DetrivoresConsume decaying producers and consumers

Food Chain Energy is lost in each step up a food chain Only 10 percent of the energy from one level on the food chain is available to the next level

Food WebsMany consumers and decomposers have more than one food sourceMovement of energy occurs in complex webs rather than in simple chains

Arctic Marine Food Web

A Simplified Food Web?

Energy PyramidProducers comprise most of the mass of the biotic part of an ecosystemThis is the ONLY place where energy (solar) enters the ecosystemEnergy is always lost in the form of heat, so energy transfers are no more than 10% efficientEach trophic level must be supported by a 10/1 energy ratio below itEnergy pyramids show the reduction of available energy at each higher trophic level

The 10% Rule

BIODIVERSITYBIODIVERSITY

BIODIVERSITYrefers to the variety of species in a specific areaincreases as one moves toward the equator (WHY?)

Why is biodiversity important?Biodiversity boosts ecosystem productivity where each specie, no matter how small, all have an important role to play.A large number of plant species means a greater number of cropsGreater species diversity ensures natural sustainability for all life formsHealthy ecosystem can better withstand and recover from a variety of disasters.

BIODIVERSITYsupports many basic natural services for humans, such as fresh water, fertile soil and clean airhelps pollinate our flowers and crops, clean up our waste and put food onthe table

Loss of Biodiversity

Threats to Biodiversity

Habitat Loss

Habitat Degradation

Habitat Fragmentation- where habitat is divided in to or broken down into smaller habitats.

Edge Effect- effect of placing side by side opposing environments on an ecosystem.

Water Pollution

Land Pollution

Exotic Species

Exotic Species

Conservation of BiodiversityConservation Biology study and implementation of methods to protect biodiversityLegal Protections of speciesPreserving habitatsHabitat corridors - an area of habitat connecting wildlife populations separated by human activities or structures.

Conservation of BiodiversityWorking with people (park rangers and the like)Reintroduction and species preservation programsCaptivityProtecting plant species

InteractionsinEcosystems

HabitatAll of the biotic and abiotic factors in the area where an organism livesLion habitat

Ecological NicheAll of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduceFood Abiotic conditions Behavior

CompetitionCompetition is when organisms compete for the same resources. This is a negative relationship because both organisms are harming each other (Campbell).InterspeciesIntraspecies

Organisms competing can be from within the same species for example, two male elk fighting for a female mate. Elephants also fight each other so that the dominant elephant will get to breed with the female.

Competition can be also found in two different species. A lizard and a frog can compete for a similar food they eat such as a small insect. This type of competition is only found when two different species share an ecological niche that they must compete over.

Competitive ExclusionWhen two species are competing for the same resources, one species will be better suited to the niche, and the other species will be pushed into another niche or become extinctInvasive species may outcompete organisms that are native to a particular region

PredationThe process by which one species captures and feeds upon anotherHeterotrophs can prey on autotrophs and other heterotrophs

Predator Prey CyclesPrey outnumber predatorsIncreasing numbers of prey promote increases in predator populations

SymbiosisA close ecological relationship between two or more organisms of different species that live in direct contact with one anotherMutualismCommensalismParasitism

MutualismAn interspecies interaction in which both species benefitFlowers and pollinating insectsHumans and intestinal E. coliClown fish and anemones

CommensalismA relationship between two organisms in which one receives an ecological benefit from another, while the other neither benefits or is harmedMany ecologists believe that commensalism is rare, and that most such relationships are probably subtle mutualism or parasitism

ParasitismA relationship in which one species benefits while the other is harmed.Many parasites have complex lifecycles involving more than one hostSeen Alien ?

The Parasitic Life Cycle of the Tse-Tse Fly

Tapeworm lifecycle

ParasitoidismA parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilizes or kills, and sometimes consumes, the host.

a cicada killer wasp is paralyzing a cicada with a sting. The wasp will then lay eggs inside the abdomen of the still living cicada. When the larva hatch, they will eat their way out of the cicada.

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