Interactions between species and their environment Ecosystem Dynamics Interactions between species and their environment

Does the Mountain care if the Wolf is there? Yes? No?

“Thinking like a Mountain” “Only the mountain has lived long enough to listen objectively to the howl of the wolf.” –Aldo Leopold “In wildness is the salvation of the world” ― Henry David Thoreau

Overview Questions What are the abiotic and biotic components of an ecosystem? How is life on Earth sustained? How can the health of an ecosystem be evaluated? How have humans impacted ecosystems?

Ecosystem Components- key physical and chemical factors BIOTIC – living Plants (producers) Animals (consumers) Bacteria (decomposers) Fungi (decomposers) Detritivores Detritus feeders Scavengers ABIOTIC – non living Aquatic: ( dissolved nutrients, pH, salinity, dissolved oxygen, temperature, light penetration,currents) Terrestrial: (pH, nutrient availability, composition, temperature, humidity, sunlight, wind,fire frequency, altitude, latitude)

Biosphere (Ecosphere) Ecosystem Structure Individual Organism Population Community Ecosystem Biosphere (Ecosphere)

Biosphere Ecosystems Realm of ecology Communities Populations Universe Galaxies Biosphere Solar systems Planets Earth Biosphere Ecosystems Ecosystems Communities Populations Realm of ecology Organisms Communities Organ systems Organs Figure 3.2 Natural capital: levels of organization of matter in nature. Ecology focuses on five of these levels. Tissues Cells Populations Protoplasm Molecules Atoms Organisms Subatomic Particles

Individual Organism- organisms are grouped into different species based on certain characteristics. Black Footed Ferret ( Endangered species) Photo credit: Ryan Hagerty ; U.S. Fish and Wildlife Service

Population Individuals of the same species living together in an area. Photo credit by Kevin Bell; U.S. Fish and Wildlife Service

Community All the various species ( plant and animal ) interacting in a particular area. Photo Credit: George Gentry: U. S. Fish and Wildlife Service

Ask: What are the biotic and abiotic factors in the photo above Ask: What are the biotic and abiotic factors in the photo above? How many can you list? Ecosystem The biotic (living) and abiotic (non-living) factors in a particular area. Photo Credit: U. S. Fish and Wildlife Service

Biological Communities -Biological communities differ in the number and types of species Species diversity- the number of different species a community contains. Genetic diversity-variety in the genetic makeup among individuals within a species. Ecological diversity-variety of forests, deserts, grasslands, oceans, streams, and lakes interacting with one another and with their nonliving environment.

BIODIVERSITY Figure 3-15

Have You Thanked the Insects Today? Many plant species depend on insects for pollination. Insect can control other pest insects by eating them.

Silent Spring??? …if all insects disappeared, humanity probably could not last more than a few months [E.O. Wilson, Biodiversity expert]. Insect’s role in nature is part of the larger biological community in which they live.

It’s an Insect world! Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics.

Habitat or Niche? The environment in which a species population ( or an individual organism) lives is called its HABITAT. HABITAT = “HOME” The relational position of a species in its ecosystem; how a species uses the resources in an area is called its ECOLOGICAL NICHE NICHE = “OCCUPATION”

NICHE TYPES The maximum range of environmental conditions under which an organism could exist if there were no competing species describes its fundamental niche. Because of direct and indirect interactions with other organisms, species are usually forced to occupy a niche that is narrower than its fundamental niche. This is called the realised niche.

Intra-specific Competition: Competition for resources between individuals of the same species. Photo credit: Dave Menke and Christopher Serbeck; U.S. Fish & Wildlife Service That’s my salmon! Back off #@*!

Inter-specific Competition : Competition for resources between different species living in the same community. Photo credit: Dave Menke and Christopher Serbeck; U.S. Fish & Wildlife Service

How can the health of an ecosystem be evaluated? Indicator Species – a species who presence, absence, or abundance can be used to assess the health (presence of pollutants, etc) of an ecosystem. Example: Frogs are a good indicator species because their life cycle includes phases in water and land. Keystone Species – a species which plays a crucial role in maintaining the structure of the ecosystem despite its abundance. An ecosystem may experience a dramatic change if this species is removed or negatively impacted. Example: Sea otters , sea stars, jaguars, alligators

Native Species A species indigenous to a given area. Example: Whooping Crane; migratory crane native to Texas. Also an endangered species due to habitat loss. Photo credit: U.S. Fish and Wildlife Service

Invasive Species A non-native species of plant or animal whose presence negatively impacts the balance of the ecosystem community. These species often are purposely or accidentally introduced by humans. Example: European Starling – introduced to the U.S. as a plan to have all birds mentioned in the works of Shakespeare. Destroys crops and competes with native species. Photo Credit: Dave Menke; U.S. Fish and Wildlife Service

Some Characteristics of Invasive Species Rapid reproductive rate Rapid growth Tolerance to wide range of abiotic factors Lack of natural predators or unusually effective defense mechanisms Compete aggressively for resources Estimated cost in the U.S. for damage and control of invasive species is $100 billion per year. Photo credit:Kudzu; invasive Japanese non-native vine Scott Ehart ( public domain)

Carrying capacity and Limiting factors Carrying capacity – the maximum number of of a species that can be indefinitely sustained by a specific ecosystem given the resources available. Limiting factor(s) – a population can be limited by the availability of matter and energy resources; Ex: food, water, space, temperature, and pH.

Range of Tolerance A given population will thrive within a particular range of abiotic factors. Outside of that optimal range will be found less and less individuals of a population. Example: pH range of tolerance for a species of fish in an aquatic ecosystem is between 6.9 and 7.5. pH’s less than 6.9 and greater than 7.5 will have less individuals able to survive.

Range of Tolerance

Factors That Limit Population Growth The physical conditions of the environment can limit the distribution of a species.

Human impacts on an Ecosystem “H.I.P.P.O” H – Habitat destruction, fragmentation or degradation I- Invasive species P – Pollution P- Population increase of humans O- Overhunting; overharvesting

Solutions Goals, strategies and tactics for protecting biodiversity. Figure 3-16