Environmental Science CH.4 (EXAM 1)

Acclimation

- the ability of an organism to respond immediately to the changing environment (house plants) ~Put in new envionment, will adjust, might wilt and turn brown

Primary Succession

A community begins to develop on a site previously unoccupied by living organisms. Example: A lava flow creates a new land area that is colonized. ~First species to come along, breakdown to make soil, excrete nutrients, etc. EX: Bare rocks are colonized by lichens and mosses, which trap moisture and build soil for grasses, shrubs, and eventually trees

Adaptions to Avoid Predation

As predators become more efficient, the prey evolve defenses (thorns, toxic chemicals, etc.). Over time predator and prey evolve in response to one another (coevolution: evolve together, compliment one another). Species with chemical defenses often evolve warning coloration with Batesian Mimicry or Mullerian Mimicry)

Tolerance Limits Graph

Bell shaped ~Lower limit of tolerance: Zone of tolerance (species absent) and Zone of Physiological Stress (species infrequent and do not reproduce) ~Optimal range (species abudedant) ~Upper limit of tolerance: Zone of Physiological Stress (Species infrequent) and Zone of Tolerance (species absent)

Ecological Succession

Communities in transition go in three phases ~Primary succession, secondary succession, climax community

Limitations where an Organism can Live

Environmental factors that determine where an organism can live include: • Physiological stress due to inappropriate levels of moisture, temperature, pH, light, nutrients. • Competition with other species • Predation, parasitism, disease • Luck - individuals move to a new and suitable location by chance (e.g. organism moved to a different beach after a storm)

Principle of Competitive Exclusion

Gause proposed the principle of competitive exclusion which states that no two species can occupy the same ecological niche at the same time. The one that is more efficient at using resources will exclude the other.

Batesian Mimicry

Harmless species mimic the warning coloration of harmful species to gain protection ~hoping their predators think they are more harmful than they are EX: a longhorn beetle looking like a wasp (Keep from being eaten by other predators, Evolved same coloration, beetle NOT harmful)

Interspecific competition

INTER = between competition between members of different species aka predator pray relationships

Intraspecific competition

INTRA= within competition among members of the same species which can be reduced if: • young disperse - reducing the population • exhibiting strong territoriality - force offspring and trespassing adults out of the vicinity • resource partitioning between generations - adults and juveniles occupy different niches within the community (Even in same species)

Introduces Species and Community Change

If introduced species prey upon or compete more successfully than native populations, the nature of the community may be altered. • Introduction of rats, cats, goats and pigs on islands where European sailing ships landed • Intentional introduction of exotic species (e.g mongoose) to solve problems caused by previous introductions

Critical Limits

Includes critical factor and tolerance limits.

Indicators Of Specific Environmental Characteristics

Interaction of several factors, rather than a single limiting factor often determines biogeographical distribution. • Tolerance limits may affect the distribution of young differently than adults. Species requirements and tolerances can also be used as useful indicators of specific environmental characteristics. • Trout require cool, clean, well oxygenated water so their disappearance from a stream may indicate that it is being polluted • Lichen is an indicator of air quality.

Species Interactions

Organisms compete for resources that are in limited supply: • Energy and matter in usable forms • Living space • Nesting sites • Feeding sites • Mates (For reproduction)

Community Properties Affect Species and Population

Productivity is a measure of the biological activity within a community

Productivity and Abundance and Diversity

Productivity is related to abundance and diversity, both of which depend on availability of resources, the adaptations of species, and interactions between species.

Tolerance Limits

Shelford later expanded by stating that each environmental factor has both minimum and maximum levels, or tolerance limits, beyond which a particular species cannot survive or is unable to reproduce.

Disturbance-adapted Species

Some landscapes never reach a climax community because they are characterized by periodic disturbances (such as wildfires) and are made up of disturbance- adapted species (those that tolerate or even require occasional disturbances)

Geographic isolation

Speciation can occur due to geographic isolation whereby a sub-population becomes separated from the main population and can no longer share genes with it. (No longer reproduce together)

Evolution

The change in the heritable characteristics of biological populations over successive generations • A trait must be inherited (genetic) for it to evolve. Individuals with traits that make them suited to a particular environment survive and reproduce at a greater rate in that environment than individuals with less suitable traits. (Natural selection) Better competitors survive and their offspring inherit those beneficial traits

Pioneer Species

The first colonists are termed in primary succession

Allopathic Speciation

The new population evolves independently of the first, creating a new species. This is termed allopatric speciation. A result of geographic isolation EX: squirrels in cool moist glacial forest and squirrels in warm dessert

Natural Selection

The process of better-selected individuals passing their traits to the next generation is called natural selection.

Resilience and Stability

Three types in ecosystems: constancy, inertia, renewal

Müllerian Mimicry

Two harmful species evolve to look alike ~Multiple harmful species evolve to look alike. When predators learn to avoid one species, they all benefit.

Critical Factor

Von Liebig proposed that the single factor in shortest supply relative to demand is the critical factor in a species distribution. ~The factor closest to the limits is the critical factor that determines where an organism can live. • Also called the Law of the Minimum

Example of Resource Partitioning

Warblers: ~Feed in different portions of trees ~Bottom, top, outside ~Not occupying the same niche at the same time ~Feeding off the same tree

Parasitism

a form of predation, is also sometimes considered a symbiosis because of the dependency of the parasite on its host (Flee can't live without the host)

Renewal

ability to repair damage after a disturbance

Secondary Succession

an existing community is disrupted and a new one subsequently develops at the site ~Abandon and agriculture field, over time new species will take over

Disturbance

any force that disrupts established patterns of species diversity and abundance, community structure, or community properties e.g. storms, fires, logging. (Natural or otherwise) Disturbance tends to disrupt the superior competitors the most and allows less competitive species to persist.

Predator

any organism that feeds directly on another organism, whether or not this kills the prey. Example: a flea feeds on my dog but does not kill it.

Mutualism

both organisms benefit from their association (e.g. a fungus and an alga combine to make a lichen)

Ecotones

boundaries between adjacent communities • Sharp boundaries - closed communities • Indistinct boundaries - open communities • Complex landscapes include contrasting environments, transition zones, and corridors connecting large patches • Edges are biologically rich, but core areas are critical for many species ~Species on edge —> find prey easily in open field ~Core —> top carnivores

Genetic Drift

chance events that cause genes to be lost from a population through generations of reproduction. ~Brown beatle moving into green beatle popualtion

Mutations

changes in DNA coding sequence that occur by chance (random mistakes in DNA replication, exposure to radiation, exposure to toxins...) • Only those in the reproductive cells impact natural selection Evolution is brought about by many mutations accumulating over time - some are beneficial, others are not

Climax Community

community that develops last and remains the longest ~Doesn't necessarily stay forever, can revert back to secondary succession if disturbances occur

Ecological Niche

describes the functional position of an organism in its environment Comprises: • The habitat • The organism's activity pattern: when is it active? (Nocturnal, during the day, etc.) • The resources it obtains from the habitat - food

Net Primary Productivity

energy left after respiration (Left in the plant after respiration)

Clustered/Clumped Distribution

for protection, mutual assistance, reproduction, access to resources ~I.e school of fish

Generalist

has a broad niche (brown rat) ~not pickey, will eat anything. I.e. rats active at night

Specialist

has a narrow niche (giant panda) Just eat bamboo

Edge Effects

important aspect of community structure is the boundary between one habitat and adjacent ones ~Can have well defined edge effects forest and agriculture field (Easy to see where when ends and other begins)

Random distribution

individuals live wherever resources are available ~i.e random red flowers among all blue flowers

Taxonomy

is the study of organisms and their relationships. It traces how organisms have descended from common ancestors. Scientists assign every species a Latin name with two parts (a binomial) so that everyone can recognize a particular organism accurately. For example, Pinus resinosa can commonly be referred to as the red pine, Norway pine, or just as a pine. Organisms are then categorized into broader taxonomic categories such as kingdoms, phyla, families, genera, etc.

Constancy

lack of fluctuation in composition or function

Competition

leads to resource allocation (Who gets to use resources and who doesn't) ~Two types: intraspecific competition and interspecific competition

Diversity

number of different species, ecological niches, or genetic variation

Uniform Distribution

often the result of competition ~spread out equal distances

Commensalism

one species benefits while the other neither benefits nor is harmed (e.g. a bromeliad growing on the trunk of a tree absorbs water and nutrients dripping down the tree trunk without harming the tree) (Helping one, not harming the other)

Sympatric Speciation

organisms continue to live in the same place but become isolated by some other means. Example: Some fern species have doubled the number of chromosomes they have. This prevents them from breeding with the population from which they originally came and effectively creates a new species.

Keystone Species

plays a critical role in a biological community relative to its abundance. (Without them the community suffers) • Helps to maintain the structure of the ecological community • If removed, community changes greatly • Often not top predators • Many pollinators are keystone species • Worms are keystone species in soils EX: kept bed will be destroyed if there are too many sea urchin (otters eat)

Primary Productivity

rate of biomass production. Used as an indication of the rate of solar energy conversion to chemical energy (through photosynthesis) ((Rate at which plants/photosynthetic organisms produce organic compounds into ecosystem)) *the cause: primary produces, the plants Tropical forests, coral reefs, and estuaries have some of the highest levels of productivity. • Abundant light, moisture, nutrients, and warm temperatures

Inertia

resistance to perturbation (Disturbance)

Ecological Structure

spatial distribution of individuals and populations within a community Types: random distribution, clustered/clumped distribution, uniform distribution *Distribution can be vertical as well as horizontal. (Ground/water surface down And along ground/water surface and layers) The physical environment and biological interactions determine these patterns

Resource Partitioning

species co-exist in a habitat by utilizing different parts of a single resource. Example: swallows eat insects during the day and bats eat insects at night.

Predator-mediated Competition

superior competitor in a habitat builds up a larger population than a competing species • Predators take note and increase the hunting pressure on the superior species, reducing its abundance and allowing the lesser species to increase its population (Predictor reducing the abundance of superior competitor, Allowing inferior competitions to exist)

Adaptation

the acquisition of genetic traits that allow a species to survive in its environment ~genetic change Adaptation is explained by Charles Darwin's theory of evolution by natural selection.

Speciation

the development of a new species.

Complexity

the number of trophic levels and number of species at each trophic level in a community ~need complex feeding chain • Diverse community may not be complex if all species are clustered in a few trophic levels, forming a relatively simple food chain. • Highly complex and interconnected community may have many trophic levels, some of which can be compartmentalized. • In the tropical rainforests, herbivores are grouped based on the way they feed on plants • Fruit eaters, leaf nibblers, root borers, seed gnawers, and sap suckers (compartmentalized)

Habitat

the place or set of environmental conditions in which a particular organism lives

Selection Pressure

the selection pressures on the two populations are different if the populations are isolated. Population traits shift over time.

Abundance

total number of organisms in a community (Plants and animals)

Symbiosis

two or more species live intimately together with their fates linked. ~Three types of symbiosis: mutualism, commensalism, and parasitism

Mechanisms that Promote Diversity of Species

~Acclimation and Adaption

Six Kingdoms

~Animals ~Fungi ~Plants ~Archeabacteria ~Eubacteria

Isolation causes two populations to diverge due to

~Genetic drift and Selection Pressure

Introduced Species and Community Change Exampples

~Mongoose—eat rats, fail ~Zebra muscles — fail almost killed all life in Lake Erie ~Kudzu — control erosion, chokes trees out ~Nutria — min veg in wetland areas, pull out by roots, fail ~Soy beans ~Cattle

Other Mechanisms of Evolution

~Mutation ~Natural Selection (Selection pressure) ~Gene Flow ~Genetic Drift (chance event)

Outcomes/Causes of Sympatric Speciation

~Temporal isolation (time difference prevents from reproducing) ~Behavioral Isolation (birds and frogs different songs, only reproduce with same song) ~Polyplodity (New species, when pollinate turn into subspecies, have both characteristics)

Abundance and Diversity

• Abundance of a particular species is often inversely related to community diversity. (Less amount of one species if there is more of them) • As a general rule, diversity decreases and abundance within species increases when moving from the equator to the poles.

Coevolution

• Leads to close evolutionary relationships between many species • Here is a star orchid and the specially adapted hawk moth that pollinates it • Evolved together so moth could reach the bottom of the nectary with its long proboscis ~two species evolve together to have this relationship

Tropical Rainforest: Diverse and Complex

• Trees form layers, each with a different amount of light and a unique combination of flora and fauna • Many insects, birds, and mammals live their entire lives in the canopy • A single hectare can have 450 tree species and many times that many insects • With so many species, the ecological relationship are complex and highly interconnected