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Ecosystem diversity

the number of different habitats available in a given area 

Species diversity

the number of different species in an ecosystem, and the balance or evenness of the population sizes of all species in the ecosystem

Genetic diversity

how different the genes are of individuals within a population (group of the same species)

Biodiversity

diversity of lifeforms in an ecosystem; measured on all three different levels

Species richness

total number of different species found in an ecosystem.

Species Evenness

a measure of how all of the individual organisms in an ecosystem are balanced between different species.

“Bottleneck” Event

An environmental disturbance (such as a natural disaster or human habitat destruction) that drastically reduces population size and kills organisms, regardless of their genomes.

Bottleneck events do what

reduce genetic diversity, making them more vulnerable to future disturbances. The higher genetic diversity, the more resilient.

Inbreeding

when organisms mate with closely-related “family” members

Inbreeding Depression

Can lead to a higher chance of offspring having harmful genetic mutations, because they’re getting similar genotypes from both parents

Ecosystem Services

Goods that come from natural resources or services that ecosystems carry out that have measurable economic value to humans.

Provisioning

Goods taken directly from ecosystems or made from natural resources (wood, paper, food).

Ex: fish, hunting animals, lumber (wood for furniture/buildings) naturally-grown foods like berries, seeds, wild grains, honey

ex. of disruption: overfishing

Regulating

Natural ecosystems regulate climate and air quality, reducing storm damage and healthcare costs.

ex. Trees in a forest sequester (store) CO₂ through photosynthesis, which reduces rate of climate change and lessens damage caused by rising sea level and reduces crop failure from drought 

ex. of disruption: deforestation

Supporting

Natural ecosystems support processes that we do ourselves, making them cheaper and easier (ex. bees pollinate crops)

Ex. Bees and other insects pollinate our agricultural crops, leading to more crop production and higher profits

ex. of disruption: pollinator habitat loss

Cultural

Money generated by recreation (parks, camping, tours) or scientific knowledge

Ex. Beautiful landscapes draw tourists who pay to enter parks, spend money at local stores/restaurants, or pay camping fees

ex. of disruption: deforestation, land and water pollution, urbanization

Island Biogeography

The study of ecological relationships and community structure on islands

Rules of Island biogeography

1. Larger islands support more total species.

2. Islands closer to the “mainland” support more species.

Adaptive radiation

single species rapidly evolving into several new species to use different resources and reduce competition 

(happens on islands because of limited space and resources, creating unique conditions for evolution and more pressure for species to adapt to narrower niches)

ex: Galapagos finches, beaks evolve to fit food

Ecological Range of Tolerance

Range of conditions (such as temperature, salinity, pH, or sunlight) that an organism can endure before injury or death result

Ex: salmon have a basic range of tolerance for temperature from 6^o to 22^o C, but some individual salmon have adaptations that give them a range of tolerance that is outside the basic range for the species. 

Optimum range

range where organisms survive, grow, and reproduce

 Zone of physiological stress

range where organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc.

Zone of intolerance

range where the organism will die (ex: thermal shock, suffocation, lack of food/water/oxygen)

Natural Disturbances

A natural event that disrupts the structure and or function of an ecosystem

ex: tornados, hurricanes, asteroids, forest fires, drought

periodic

 occurs with regular frequency (ex: dry-wet seasons)

episodic

occasional events with irregular frequency (ex: hurricanes, droughts, fires)

random

no regular frequency (volcanoes, earthquakes, and asteroids)

Genetic diversity exists because:

• Random mutations (while DNA is being copied) create new traits

• Crossing over (during Prophase I of meiosis) creates new combinations of genes (and therefore, new traits)

Adaptation

a new trait that increases an organism’s fitness (ability to survive and reproduce)

Natural selection

organisms that are better adapted to their environment survive and reproduce more offspring.

Selective pressure (or force)

the environmental condition that kills off individuals without the adaptation

ex. a hawk eats all the mice that don’’t learn to hide from it until they’re all gone

The more rapidly an environment changes,

the less likely a species in the environment will be to adapt to those changes.

ex: if the ocean warms too quickly, many species of fish may not be able to migrate before they run out of oxygen and suffocate

Ecological Succession

A series of predictable stages of growth that a forest goes through.

Primary succession

starts from bare rock in an area with no previous soil formation

ex. Moss and lichen spores carried by the wind grow directly on rocks, breaking them down to form soil

Secondary succession

starts from already established soil, in an area where a disturbance (fire/tornado/clear-cutting) has cleared out the majority of plant life

ex. Grasses, sedges, wildflowers, and berry bushes have seeds dispersed by wind or animal droppings 

Pioneer (or early succession species)

appear first, when the ground is simply bare rock after a disturbance

ex: moss, lichen (bare rock) → wildflowers, raspberries, grasses/sedge

Mid-successional species

appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death

ex: shrubs, bushes, fast-growing trees like aspen, cherry, and pine

Late successional or climax community species

appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early- and mid-successional species

ex: maples, oaks, other large trees

 “keystone” species

a species whose activities have a particularly significant role in determining community structure.

“indicator” species

 a plant or animal that, by its presence, abundance, scarcity, or chemical composition, demonstrates that some distinctive aspect of the character or quality of an ecosystem is present

Invasive Species

not native to an area (often introduced unintentionally by human transport) and causing ecological distress.

• Have no natural predators to control their populations

• Are highly competitive for resources (i.e., aggressive feeders or fast growers) 

• Can thrive well in their non-native habitats

• Have high biotic potential (growth rate) and low parental care

• Are highly adaptable

• Have diverse habitat and food needs

Control/Removal Methods

• LEGAL: Laws preventing transport of invasives (firewood for emerald ash borers)

• PHYSICAL: Careful boat cleaning and inspection (zebra mussels)

• PHYSICAL: Removal (hunting pythons, detaching zebra mussels, pulling plants out, cutting trees down)

• BIOLOGICAL: Introduction of natural predators

How Do Species Become Endangered?

Poaching, Invasives, Climate Change, Special habitat or food needs

CITES

 “Convention on International Trade in Endangered Species of Wild Fauna and Flora”

international agreement for countries to set up agencies to monitor import and export of endangered species

Endangered Species Act

 U.S. law giving USFWS power to designate species as endangered or threatened, monitor trade, and purchase land critical to these species’ habitats.

ICUN

Extinct, Threatened, Least Concern

Specialists

Most likely to be endangered or become extinct

• Less likely to move to a new habitat

• Less likely to adapt to new conditions

• Disadvantaged by rapidly-changing habitat conditions

  ex. panda

Generalists

Least likely to be endangered or become extinct

• More likely to move to new habitat

• More likely to adapt to new conditions

• Advantaged by rapidly-changing habitat conditions

  ex. raccoon

Habitat Fragmentation

 the breaking of larger, continuous habitats into smaller, isolated patches; disrupts breeding, food webs and migration.

edge habitat

where two ecosystems such as forest/grassland or ocean/river (estuaries) meet, and has different characteristics than in the middle of each ecosystem