Environmental Science Exam 2

Biodiversity

the mix of different animals, plants, fungi, and microorganisms that make up our natural world. More specifically, biodiversity describes how many types of organisms are living in an ecosystems

Biomes

Distinctive complex of plants created and maintained by climate

Ecosystems

a physical and biological system formed by a community of living beings that inhabit a physical environment

Habitats

Place where a species is adapted to live based on the conditions and resources

Niche

the role the species plays, and includes the type of food it eats, where it lives, where it reproduces, and its relationships with other species

Species

group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding

Population

A subset of individuals of one species that occupies a particular geographic area

Biological community

an interacting group of various species in a common location

Keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed, the ecosystem would change drastically

Keystone predators

keep the population and range of their prey in check and impact other predators as well as other animal and plant species farther down the food chain

Keystone prey

serve as a critical food source for predator populations, resilient creatures

Ecosystem engineer

instead of impacting food supply, these animals create, modify, or maintain the landscape around them

Mutualists

two or more species that engage in reciprocally vital interactions

Keystone plants

provide a critical source of food and/or shelter for other species

Indicator species

serve as a measure of the environmental conditions that exists in a given locale

Endemic species

those that are restricted to a geographical area and do not occur naturally in any other part of the world

Invasive species

plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction cause if likely to cause more harm

Competition

interaction where both species can be harmed (- -)

Interspecific competition

between species

Intraspecific competition

within species

Resource partitioning

division of a resource and specialization in different parts of it

Predation

one organism kills and consumes another (+ -)

Symbiosis

closely living together of members of two or more species

Commensalism

interactions between two organisms living together in more or less intimate association in a relationship in which one benefits and the other is unaffected

Mutualism

an interaction between individuals of different species that results in positive (beneficial) effects on per capita reproduction and/or survival of the interacting populations

Parasitism

 a relationship between the two living species in which one organism is benefited at the expense of another

Amensalism

association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected

Conversion

 a fundamental change in a natural habitat, usually caused by human activity in that area

Fragmentation

when large blocks of habitat are cut into smaller pieces by development between roads or housing

Simplification

the action of changing a landscape from containing a diverse range of both plant and animal species into an area where only a few species can now exist

Overexplotation

refers to harvesting a renewable resource to the point of diminishing returns

Human-mediated speciation

humans drive rapid evolution through relocation, domestication, hunting and novel ecosystem creation and emerging technologies could eventually provide additional mechanisms

Pollution

freshwater wildlife are most impacted by pollution

Invasive species

capable of causing extinctions of native plants and animals, reducing biodiversity, competing with native organisms for limiting resources and altering habitats

Land management

human land-use is a primary cause of biodiversity loss

Changing species interactions

there are a vast number of interactions between species. Some interactions are direct, predation, some are indirect (food cycle)

Bioaccumulation

the net accumulation of a contaminant in or on an organism from all sources including water, air, and diet

Biomagnification

the concentration of toxins in an organisms as a result of its ingesting plants or animals in which the toxins are widely disbursed

Climate

long term, established weather patterns

Disturbance

a temporary change in environmental conditions that cause a pronounced change in an ecosystem, often act quickly and with great effect, to alter the physical structure or arrangement of biotic and abiotic elements

Genetic diversity

looks at difference among individuals within a population, or a difference across different populations of the same species

Species diversity

the number of different species in a particular ecosystem or on Earth

Ecological diversity

the types of functional units formed by living communities interacting with their environments

Biological diversity vs. ecological diversity

while biodiversity refers to the overall variety of life on Earth, including different species, genes and ecosystems, ecological diversity specifically focuses on the variety of ecosystems within a given area, encompassing the different habitats and ecological processes present

Diversity index

a measure of species diversity to determine the number of individuals of each species present in an area

Abundance

the total number of organisms in an area, doesn’t matter what species they are

Species richness

number of different species in an area. Does not matter how abundant they are. The greater the number of species, the more rich the community

Species evenness

a description of the distribution of abundance across the species in a community. Species evenness is highest when all species in a sample have the same abundance

Simpson’s index

suggests that diversity is inversely related to the probability that two individuals picked at random belong to the same species

Shannon-Wiener Index

Most widely used to measure species diversity: Determined by both the number of different species and the even distribution of individuals among those species (relative dominance)

Species richness

based solely on the number of species found in the given area and does not reflect the relative dominance of species

Species evenness

Using species richness (R) and the Shannon-Wiener index (H’), you can also compute a measure this

Green Revolution

a Post WWII set of events that created the next boom in agricultural activity

Demand-based agriculture

determined by economic demand

Resource-based agriculture

determined by resource availability

Cash crops

• may provide non-food products (latex, tobacco)

Subsistence crops

crops that produce food resources

Corn

Most produced crop in the United States

Soil

a complex mixture of minerals, decomposing organic materials, and living organisms

Soil horizon

six distinct layers of the soil

Arable land

land that is fertile and can be used to grow crops

PVR soils

permeable, versatile, and resilient

Mechanical erosion

the physical breaking down of rock by wind and water

Chemical erosion

changes in the molecular structure of the rock because of chemical reactions

Desertification

permanent loss of soil productivity due to the overuse of the soil

Salinization

occurs from over irrigation

Conversion/fragmentation

refers to losing fertile soils to other uses, such as building urban areas or roads

Irrigation

application of water to soil

Three types of irrigation

• Overhead sprinklers, least efficient

• Underground drip, most efficient

• Center-pivot

Riparian zones

areas of land that connect the upland zone to the aquatic zone, controlling the flow of water, sediment, nutrients, and organisms between the two

Four steps of eutrophication

• Excess nutrients: first, farmers apply fertilizer to the soil. Excess nutrients then run off from the field to the water

• Algae bloom: the fertilizer, which is rich in nitrate and phosphate, sparks the overgrowth of algae in water bodies

• Oxygen depletion: when algae forms, it blocks sunlight from entering water and uses up oxygen

• Dead zones: finally, water that is completely depleted of oxygen becomes a dead zone and can no longer support life

Artificial selection

involves selecting the healthiest plants, so the species will get stronger over time

Crossbreeding

involves combining the DNA from two different plant species

Inorganic fertilizer

synthetically made from minerals

Organic fertilizer

derived from plant and animal matter

Ecological/biological pest control

• Based on knowledge of the pest’s life cycle and ecological relationships

• May be other organisms or chemicals

• May be highly specific to one organism

• May manipulate some aspect of the ecosystem

Chemical pest control

• Gives only short-term protection

• Has highly damaging side effects to other organisms

• Chemicals remain on food and in the environment

• Pesticides, herbicides, and insecticides

Resurgence

• pest population recovers and even explodes

  • Occurs after the pest has almost been eliminated

Secondary pest outbreak

• insects that were originally of no concern explode and create new problems

  • They quickly become resistant to pesticides

Pesticide treadmill

• use of pesticides which increases resistance and secondary-pest outbreaks

Integrated pest management

• technique to evaluate a crop and its pests as part of a full interconnected ecological system