EXAM 2

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.)

critical factor

factor closest to the limits that determines where an organism lives

Tolerance limits

Limit to which an organism can withstand changes in the environment (may affect the distribution of young differently than adults)

Generalist

has a broad niche (brown rat, hog, opossum) = eats anything

Resource Partitioning

species coexist in a habitat by utilizing different parts of a single resource. ex. swallows eat insects during the day and bats eat insects at night

Speciation

development of a new species

Allopatric speciation

new population evolves independently of the first, creating a new species. (Speciation by geographic isolation is termed allopatric speciation.)

Directional selection

one trait is being favored and the other is being eliminated so the population shifts toward one trait

Stabilizing selection

the range of a trait is narrowed

Disruptive selection

traits diverge toward two extremes

Interspecific competition

competition between members of different species

Predator

any organism that feeds directly on another organism, whether or not this kills the prey, Parasites are predators.

ex. Mosquitoes only eat the blood

Symbiosis

two or more species live intimately together with their fates linked

Mutualism

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

Parasitism

a form of predation, is also sometimes considered a symbiosis because of the dependency of the parasite on its host

ex. Cowbird lay egg in nests of other bird

keystone species

plays a critical role in a biological community that is out of proportion to its abundance

ex. sea otter eats sea urchins- keeping their population under control; so the urchins don't eat all the kelp season

Primary productivity

rate of biomass production. Used as an indication of the rate of solar energy conversion to chemical energy

Tropical forests, coral reefs, and estuaries have some of the highest levels of productivity

Diversity

number of different species, ecological niches, or genetic variation

General Rule for abun & diver

diversity decreases and abundance within species increases when moving from the equator to the poles

Ecological succession

an orderly sequence over time of species living on a site

One community is succeeded by another

Primary succession

A community begins to develop on a site previously unoccupied by living organisms. Ex: a lava flow creates a new land area that is colonized.

Pioneer species

first colonists

Secondary succession

an existing community is disrupted and a new one subsequently develops at the site

Ex. Secondary succession

in a disrupted community

ex. Chestnut blight, dutch elm disease, ash borers

Selective harvest of most valuable timber

Clear-cutting of timber

Abandoned farmland

Disturbance-adapted species

pioneers of disturbed area, ex. Jack pine

P. Question Chap.4

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.

Biome temp & precipitation

Temperate and precipitation are the most important determinants in biomes distribution

Temperature and precipitation also change with altitude. (Higher = colder)

Temperature-controlled biomes often occur in latitudinal bands

Vertical Zonation

vegetation zones defined by altitude. (higher altitudes get colder and wetter)

Savanna

Tropical grassland with trees

Wildfires in dry season

Distinct wet and rainless seasons

Too little rain for forests

Temperate shrubland

Characterized by warm, dry summers and cool, moist winters = winter growing season

Evergreen shrubs, scrub oaks, pines

Fires are a major factor in plant succession.

Mediterranean

characterized by warm, dry summers and cool, moist winters

Evergreen shrubs, shrub oaks, pines

Fires are a major factor in plant succession

chaparral

Broadleaf tree ohio

American Holly has broad leaves that stay green all winter, then fall off in May

By crouse hall

Deciduous

Leaves fall and grow back

Broadleaf

wider & softer than needles

Can be evergreen where warm & rainy

Evergreen

Never loses leaves

Taiga

Northernmost edge of boreal forest

Extreme cold and short summers limit the growth rate of trees.

Tundra

Frozen most of the year

Warm enough for plants but not for trees

Woody plants survive but not with trunks

Tree line toward the equator

Vegetation line toward the pole

Marine ecosystem

Oceans cover ¾ of Earth's surface

Upwelling currents circulate nutrients from the ocean floor back to the surface.

Photosynthesis is carried out by algae or free-floating plants (phytoplankton).

Open ocean is a biological desert except for areas where nutrients are distributed by the currents.

Benthic

bottom (little to no life)

littoral zone

Area near shore

Coral Reefs

Aggregations of coral polyps that live symbiotically with algae. Their calcium-rich skeletons build up the reef.

coral bleaching

corals expel their agal partners and then die.

Caused by very hot water

Mangroves

trees that grow in saltwater along tropical coastlines

Help stabilize shoreline (littoral zone)

Nurseries for fish, shrimp, crabs

Can be cut for timber, firewood

Soil

renewable resource that develops gradually through the weathering of rocks and the accumulation of organic material.

Organic

Living & decaying organisms

Air

(unless saturated with water!)

N2, O2, H2O, CO2

Soil texture

(the amount of sand, silt and clay in the soil) is the most important characteristic of soil types.

Loam soils

considered best for agriculture because they are a mixture of sand, silt, and clay. (balanced)

Top soil V. Subsoil

Upper horizons more organic

Lower horizons more mineral

O horizon (organic layer)

Leaf litter, most soil organisms and partially decomposed organisms

B Horizon (subsoil)

Often dense texture due to clays (washed in)

C Horizon

Weathered rock fragments with little organic material

Desertification ex

Can be natural:

Climate change

Volcanic event

Fire

Usually done by humans:

Clearing vegetation

Overgrazing by domestic animals

More frequent fire

All 3 accelerated by climate change

Waterlogging

soil stays saturated

Salinization

mineral salts accumulate in soils; lethal to plants

Soil salinization

concentration of salts in topsoil

From evaporation of surface water

A problem in dry climates

Agribusiness

conventional set of farming practices (since WWII)

Dr. B

Since the 1970s, "US agribusiness is the practice of turning fossil fuels into food and fiber using land as a catalyst.

100% organic

must contain only organically produced ingredients and processing aids, excluding water and salt.

organic

95% organically produced ingredients (excluding water and salt).

Conventional and industrial farming

Large machines

Chemical pesticides

Chemical fertilizers

Sewage sludge

Antibiotics in feed

Synthetic hormones

Genetic engineering

Ionizing radiation

Organic farming

Plant extracts

Crop rotation

Livestock manure, compost, mulch

Only to cure disease

No "doping"

Selective breeding

Pasteurization

Natural Selection

The process of individuals suited to a particular environment passing on more of their traits to the next generation

Mutation

changes in DNA coding sequence that occur by chance (random mistakes in DNA replication, exposure to radiation, toxins)

Adaption

the acquisition of traits that allow a species to survive in its environment (Charles Darwin)

Adaption rules

A trait must be inherited (genetic) for it to evolve.

Individuals with traits that make them suited to a particular environment

Survive

Mature

Reproduce

At a greater rate in that environment than individuals with less suitable traits

limiting factor

food supply, temperature, water availability, soil nutrients, nesting sites, predators, parasites, diseases

Habitat

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

Ecological niche

describes either the role played by a species in biological community or total set of environmental factors that determine a species distribution

Ecological Niche Desc. - Functional Role

Herbivore, Carnivore, Scavenger, Parasite

Specialist

has a narrow niche (giant panda) = eats one kind of bamboo

Competitive Exclusion Principle

no two species can occupy the same ecological niche at the same time. The species that is more efficient using resources will exclude the other.

geographic isolation

sub-population can no longer share genes with the main population.

sympatric speciation

organisms continue to live in the same place but become different by some other means.

Ex. Some ferns have doubled the number of chromosomes they had before. This prevents them from breeding with the population they originally came from.

Taxonomy

study of organisms and their relationships. It traces how organisms have descended from common ancestors.

Predator-mediated competition

one species may be the best competitor in a given location or habitat, but predators may reduce its abundance and allow the weaker competitors to increase its numbers.

Net primary productivity

energy left after respiration

Climax community

community that develops last and remains the longest

Biomes

areas sharing climate, topographic, and soil conditions, and thus the same basic types of biological communities

Altitudinal zonation

vegetation zones defined by altitude (higher altitudes get colder and wetter)

Tropical Rainforest

occur where rainfall exceeds 200 cm (80 inches) per year and temperatures are warm to hot year-round

Soil in rainforests tends to be thin, acidic, and nutrient-poor

Red clay

Tropical Seasonal Forest

wet and dry seasons with hot temperatures year-round.

Deciduous

Brown and dormant much of the year but become green during the rainy season

Soil is richer than rainforest

Pelagic

water column above the bottom

Estuaries

bays or semi-enclosed bodies of brackish water that form where rivers enter the ocean

Brackish - contains salt, but less than the sea does

Breeding areas for salt-water fish, crabs, oysters, etc.

Seaports

Water

Liquid, bound, & solid phases

Mycorrhizal symbiosis

an association between plant roots and certain fungi. The plant feeds the fungus, and the fungus provides water and inorganic nutrients to the plant, enhancing growth.

Plant feeds fungus

Fungus extends reach of roots

Providing water and minerals to plants

Both grow better = mutualism

A Horizon (topsoil)

Mineral particles mixed with organic material

Desertification

conversion of productive land to desert

the loss of soil and vegetation

Particle size ranking

Plant

Rock

Gravel

Sand

Silt

Clay

Molecule

Limestone Quarry

no soil, no vegetation = desertification

Limestone Quarry ex.

That limestone quarry near rogers city, michigan is the largest on the planet

Ecological Niche Desc. - Habitat

Polar, Temperate zone, Tropical, Sunny or shady, wet or dry etc.

Latin Name

Scientists assign a binomial Latin name, Scientific binomials are underlined, or printed in italics. Only the genus is capitalized.

Intraspecific competition

competition among members of the same species, which can be reduced if:

Young disperse, Animal Defends a territory, Adults and juveniles occupy different niches

Abundance

total number of organisms in a community

Ex. Primary succession

on bare lifeless ground,

ex. Lava flow

A very hot forest fire, Retreat of glacier

Landslide

Disturbance

any force that disrupts established patterns of species diversity and abundance, community structure, or community properties e.g. storms, fires, or logging.

Kingston plains

large pine stumps in a dry grassland region

Desert

Characterized by low moisture levels

Have wide daily and seasonal temperature fluctuation

Thick trunks, no branches, few leaves

E.G. Joshua tree

Temperate Deciduous Forest

Temperate regions support lush summer plant growth when water is plentiful

Deciduous trees lose their leaves in winter as an adaption to freezing temperatures.

Ex. yellow golden leaves