units 1-2: the living world

key terms are from Princeton Review

ecosystem

a community of living organisms and its environment, contains biotic and abiotic components, result of these components interacting with one another

biotic

living components

abiotic

non-living components

evolution

biodiversity is the result of this, change in a population’s genetic composition over time

phylogenetic tree

models evolution, can be broad or specific, describes the evolutionary relationships that exist between 2 species or even the genomes of one species

speciation

process of how new species are formed

species

group of organisms that are capable of breeding with one another and incapable of breeding with other species

evolutionary fitness

Darwin, idea that individual organisms that are better adapted for their environment will live and reproduce, ensuring that their genes are part of their population’s next generation

natural selection

when a habitat (an organism’s physical surroundings) selects certain organisms to live and reproduce and others die, the population is undergoing this

selective pressure

any cause that reduces reproductive success (fitness) in a portion of a population, what drives natural selection

gene pool

total genetic makeup of the population, what changes during evolution

genetic drift

accumulation of changes in the frequency of alleles (versions of a gene) due to sampling errors (changes that occur as a result of random chance)

microevolution

when a population displays small-scale changes over a relatively short period of time

macroevolution

refers to the large-scale patterns of evolution within biological organisms over a long period of time

extinction

occurs when a species cannot adapt quickly enough to environmental change, all members of the species die

biological extinction

true extermination of a species

ecological extinction

when there are so few individuals of a species that this species can no longer perform its ecological function

commercial/economic extinction

when a few individuals exist but the effort needed to locate and harvest them is not worth the expense

population

group of organisms of the same species

community

what it is called when populations of different species occupy the same geographic area

niche

described as the total sum of a species’ use of the biotic and abiotic resources in its environment, describes the following: where the species lives, what it eats, all the other resources the species utilizes in an ecosystem

habitat

the area or environment where an organism or ecological community normally lives or occurs (ex: single tree in a forest for squirrel)

specialist

type of species- one that has a narrow niche and can only live in a certain habitat

generalist

type of species- one that has a broach niche, is highly adaptable and can live in varied habitats

competition

arises when two individuals of the same species or of different species are competing for resources in their environment

intraspecific competition

when 2 individuals that are competing are of the same species

interspecific competition

when different species are competing

competitive exclusion

when two different species in a region compete and the better adapted species wins

Gause’s principle

no 2 species can occupy the same niche at the same time and that the species that is less fit to live in the environment will relocate, die out, or occupy a smaller niche

realized niche

when a species occupies a smaller niche than it would in the absence of competition (compromised niche)

fundemental niche

the niche an organism would have if there were no competition

resource partitioning

how direct competition can be avoided, different species use slightly different parts of the habitat, but rely on the same resource

predation

occurs when a predator feeds on another prey and it drives changes in population size

predator

an organism that hunts and kills other organisms (its prey) for food

prey

an organism that is hunted and killed by another animal for food

symbiotic relationships

close prolonged associations between 2 or more different organisms of different species that may, but do not necessarily, benefit each member

mutualism

type of symbiotic relationship; both species benefit

commensalism

type of symbiotic relationship; one organism benefits while the other is neither helped nor hurt

parasitism

type of symbiotic relationship; one species is harmed and the other benefits

biomes

ecosystems that are based on land

aquatic life zones

ecosystems in aqueous environments

ecotones

transitional area where two ecosystems meet

ecozones/ecoregions

smaller regions within ecosystems that share similar physical features (ex: dif locations)

deciduous forest

a type of forest where the dominant trees shed their leaves seasonally, usually in the fall, typically found in temperate climates with distinct seasons, hardwood trees

tropical rainforest

tall trees with few lower limbs, vines, epiphytes, plants, adapted to low light intensity

grasslands

sod-forming grasses

coniferous forest/taiga

contains evergreen trees that produce needles instead of leaves and cones instead of flowers. They are well-suited to cold or dry environments because of these adaptations.

tundra

cold, treeless biome that can be found in the Arctic and on high mountains, herbaceous plants (don’t have woody stem)

chaparral

small trees with large, hard evergreen leaves, spiny shrubs

deserts (cold and hot)

cactus, other low-water adapted plants

temperate rainforest

coniferous and broadleaf trees, epiphytes, mosses, ferns, and shrubs

savanna

grasses with more widely spaced trees

epilimnion

uppermost and most oxygenated layer (freshwater)

hypolimnion

lower, colder, more denser layer (freshwater)

thermocline

line between 2 layers, temperature shifts dramatically (freshwater)

Littoral zone

begins with shallow water at the shoreline, plants and animals here receive abundant sunlight, end of this zone is defined as the depth at which rooted plants stop growing

Limnetic zone

surface of open water, region that extends to the depth that sunlight can penetrate, organisms here tend to be short-lived and rely on sunlight

Profundal zone

light cannot reach here, organisms adapted to little light, colder temp, less oxygen live in this zone

benthic zone

surface and subsurface layers of the river, lake, pond, streambed, characterized by low temperatures and low oxygen levels, inhabited by organisms that live on, in or below the sediment surface

estuary

site where the arm of the sea extends inland to meet the mouth of the river, lots of species because of high concentration of nutrients, shallow, warm and a lot sunlight

wetlands

areas along the shores of fresh bodies of water, wet inland habitats fed by only rainwater, and ephemeral (seasonally temporary) water bodies

mangrove swamps

areas of land covered in fresh water, salt water, or a combination of both, huge diversity of animals, helps prevent shoreline erosion

barrier islands

created by the buildup of deposited sediments, a long narrow island lying parallel and close to the mainland, protecting the mainland from erosion and storm

coral reef

formed by a community of living things, cnidarians are responsible for the creation of this (secrete a hard shell that provide homes and shelter for species), extremely delicate so vulnerable to physical stresses and other things

coastal zone (ocean)

closest to land, life thrives bc of abundant oxygen and sunlight, proximity to sediment surface allows for varied niches, border and extend to estuaries, beaches, and marshes

euphotic zone (ocean)

upper layers of water, warmest region of ocean water, highest levels of dissolved oxygen, supports algae that supply oxygen, photosynthesizers have adapted mechanisms to address the lack of visible light

bathyal zone (ocean)

middle region, colder and darker and does not receive enough light to support photosynthesis, less organisms here, not that much fish because of lack of nutrients, those fish that live here often lack eyes since there’s so little sunlight, populated by larger predators and other organisms

abyssal zone (ocean)

deepest region of the ocean, extremely cold temperatures and low levels of dissolved oxygen, high levels of nutrients because of decaying plant and animal matter, without plants the base of the food chain in this zone is decomposers, many creatures adapted to live here produce bioluminescence to attract prey or mates, most are adapted to the cold, low oxygen, intense pressure, using slower metabolisms and the ability to eat more when food is available to help them survive

upwellings

the process of cold, nutrient-rich water rising to the surface of the ocean, movement of water, provide new nutrient supply for the growth of living organisms in photic regions

red tide

occur when microscopic algae multiply to higher-than-normal concentrations, often discoloring the water

biogeochemical cycles

nutrients such as carbon, oxygen, nitrogen, phosphorus, sulfur, water all move through the complex cycles know as

reservoir

used to describe a place where a large quantity of a nutrient sits for a long period of time

exchange pool

a site where a nutrient sits for only a short period of time

residency time

the amount of time a nutrient spends in a reservoir or an exchange pool

Law of Conservation of Matter

matter can neither be created nor destroyed

precipitation

any form of water that falls from clouds and reaches Earth's surface

groundwater

water that is stored in the soil and rock beneath the Earth's surface

runoff

the water from precipitation that flows across the land surface instead of being absorbed into the soil, eventually reaching bodies of water like rivers, lakes, or oceans

evaporation

water is returned to the atmosphere from both the Earth’s surface and from living organisms (animals respire and release water vapor and additional gases to the atmosphere)

transpiration

in plants this process releases large amounts of water into the air

respiration

plants and animals breathe in oxygen and give off carbon dioxide (exchange pools for carbon)

photosynthesis

plants take in carbon dioxide, water, and energy from the sun to produce carbohydrates (exchange pools for carbon)

combusted (carbon cycle)

burnt (when this happens to fossil fuels carbon is released into atmosphere)

nitrogen fixation (nitrogen cycle)

nitrogen must be in present in the form of ammonia (NH3) or nitrates (NO3-) to be used by most living organisms, atmospheric nitrogen can be converted to this form by atmospheric effects like lightning storms, but most fixation is the result of actions of certain soil bacteria

nitrification (nitrogen cycle)

soil bacteria converts ammonia or ammonium (NH4+) into nitrates (NO2) and then to one of the forms that can be used by plants nitrate, (NO3-)

assimilation (nitrogen cycle)

plants absorb ammonium, ammonia ions (NH4+), and nitrate ions (NO3-) through roots

ammonification (nitrogen cycle)

decomposing bacteria convert dead organisms and other waste to ammonia (NH3) or ammonium ions (NH4+), which can be reused by plants or released into the atmosphere (volatilized)

Denitrification (nitrogen cycle)

specialized bacteria (mostly anaerobic bacteria) convert ammonia back into nitrites and nitrates, and then into nitrogen gas (N2) and nitrous oxide gas (N2O), which then rise into the atmosphere

phophorus cycle

biogeochemical process that describes the movement of _______ through the lithosphere, hydrosphere, and biosphere, involving its absorption by plants and animals, and its release back into the environment through decomposition and weathering

limiting factor

any factor that controls a population’s growth—food, space and water

terrestrial cycle

the movement of nutrients and energy within a land-based ecosystem

eutrophication

occurs when a body of water receives excess nutrients, abundance of nutrients can cause an overgrowth of algae and deplete the water of oxygen

sulfur cycle

a biogeochemical process that describes the movement of sulfur through the atmosphere, lithosphere, hydrosphere, and biosphere, involving processes like oxidation, reduction, and incorporation of sulfur compounds

autotrophs

organisms that can produce their own organic compounds from inorganic chemicals

heterotrophs

obtain food energy by consuming other organisms or products created by other organisms

producers

organisms capable of converting radiant or chemical energy into carbohydrates

anaerobic

without oxygen

chemotrophs

organisms that carry out chemosynthesis, some found in hydrothermal vents deep in ocean

Net Primary Productivity

amount of energy that plants pass on to the community of herbivores in an ecosystem

Gross Primary Productivity

amount of sugar that plants produce in photosynthesis and subtracting from it the amount of energy the plants need for growth, maintenance, repair, and reproduction