Unit 2 Megaset

population

composed of all individuals that belong to the same species and live in a given area at a particular time

community

incorporates all of the populations of organisms within a given area

limiting resource

a resource that a population cannot live without and which occurs in quantities lower than the population would require to increase in size

Density-independent factors

have the same effect on an individuals probability of survival and amount of reproduction at any population size

Die-off

population crash usually experienced after the overshoot of the carrying capacity

corridors

strips of habitat that connect separated populations that the animal travels across

community ecology

the study of species interactions, which determine the survival of a species in a habitat

competitive exclusion principle

states that two species competing for the same limiting resource cannot coexist

primary succession

occurs on surfaces that are intially devoid of soil

secondary succession

occurs in areas that have been disturbed but have not lost their soil

pioneer species

organisms that have the ability to colonize new areas rapidly and grow well in full sunshine

theory of island biogeography

demonstrates the dual importance of habitat size and distance in determining species richness

biomes

terrestrial geographic regions that have a particular combination of average annual temperature and annual precipitation and contain distinctive plant growth forms that are adapted to that climate

tundra

a biome that is cold and treeless, with low-growing vegetation

permafrost

an impermeable, permanently frozen layer that prevents water from draining and roots from penetrating

boreal forest

a biome; are forests made up primarily of coniferous (cone-bearing) evergreen trees that can tolerate cold winters and short growing seasons

temperate rainforest

a biome; moderate temperatures and high precipitation typify this biome

temp seasonal forest

a biome; are more abundant than temperate rainforests; experience much warmer summers and colder winters than temperate rainforests

shrubland; Chaparral

a biome; is characterized by hot, dry summers and mild, rainy winters

Temperate Grassland

a biome; has the lowest average annual precipitation of any temperate biome; cold, harsh winters and hot, dry summers characterize this biome

Tropical Rainforest

a biome; are warm and wet, with little seasonal temperature variation

Tropical Seasonal Forests; Savannahs

a biome; are marked by warm temperatures and distinct wet and dry seasons

Subtropical Desets

a biome; also known as hot deserts; hot temperatures, extremely dry conditions, and sparse vegetation prevail

Littoral Zone

is the shallow area of soil and water near the shore where algae and emergent plants such as cattails grow

Limnetic Zone

open water

Phytoplankton

floating algae

Profundal Zone

very deep lakes have a region of water below the limnetic zone

Benthic Zone

the muddy bottom of a lake or bond beneath the limnetic and profundal zones

Freshwater Wetland

a biome; aquatic biomes that are submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation throughout

Salt Marsh

a biome; found along the coast in temperate climates; one of the most productive biomes in the world

Mangrove Swamps

a biome; occur along tropical and subtropical coasts

Intertidal Zone

the narrow band of coastline between the levels of high tide and low tide

Coral Reefs

a biome; are found in warm, shallow waters beyond the shoreline, represent Earth's most diverse marine biome

Coral Bleaching

a phenomenon in which the algae inside the corals die which soon causes the corals to die

Photic Zone

the upper layer of water that receives enough sunlight to allow photosynthesis

Aphotic Zone

the deeper layer of water that lacks sufficient sunlight for photosynthesis

ecosystem diversity

the measure of the variety of ecosystems within a region

species eveness

tells us whether a particular ecosystem is numerically dominated by one species or whether all of its species have similar abundances

evolution

a change in the genetic composition of a population over time

microevolution

the evolution below the species level, such as the evolution of different varieties of apples or potatoes

macroevolution

the process in which genetic changes give rise to a new species, genera, family, class, or phyla

genes

are physical locations on chromosomes within each cell of an organism; determines the range of possible traits that it can pass down to its offspring

genotype

the complete set of genes in an individual

mutation

an occasional mistake in the copying process of DNA produces a random change in the genetic code

recombination

occurs as chromosomes are duplicated during reproductive cell division and a piece of one chromosome breaks off and attaches to another chromosome

phenotype

the actual set of traits expressed in that individual

artificial selection

when humans determine which individuals breed, typically with a preconceived set of traits in mind

adaptations

traits that improve an individual's fitness

genetic drift

a change in the genetic composition of a population over time as a result of random mating

bottleneck effect

a reduction in the genetic diversity of a population caused by a reduction in its size

founder effect

a change in a population descended from a small number of colonizing individuals

allopatric speciation

a process of speciation that requires geographic isolation

sympatric speciation

the evolution of one species into two species in the absence of geographic isolation

genetic engineering

techniques in which scientists can now copy genes form a species with some desirable trait and insert these genes into other species

genetically modified organisms

organisms that have had their genetic makeup modified by genetic engineering

range of tolerance

limits to the abiotic conditions they can tolerate

fundamental niche

the suite of ideal conditions

realized niche

the range of abiotic and biotic conditions under which a species actually lives

species distribution

the areas of the world in which the species lives

niche generalists

organisms that can live in a variety of habitats or feed on a variety of species

niche specialists

organisms that are specialized to lie in a specific habitat of feed on a small group of species

ecosystem

a particular location on Earth distinguished by its particular mix of interacting biotic and abiotic components

producers; autotrophs

organisms that use the suns's energy to produce usable forms of energy

photosynthesis

the process in which producers use solar energy to convert carbon dioxide and water into glucose, a form of potential energy that can be used by a wide range of organisms

consumers; heterotrophs

are incapable of photosynthesis and must obtain their energy by consuming other organisms

primary consumers

heterotrophs that consume producers

secondary consumers

carnivores that eat primary consumers

tertiary consumers

carnivores that eat secondary consumers; are pretty rare

trophic levels

successive levels of organisms consuming one another is called this

food chains

the sequence of consumption from producers through tertiary consumers

food web

take into account the complexity of nature, and they illustrate one of the most important concepts of ecology

scavengers

are carnivores, such as vultures, that consume dead animals

detritovores

organisms, such as dung beetles, that specialize in breaking down dead tissues and waste products (referred to as detritus) into smaller particles

decomposers

the fungi and bacteria that complete the breakdown process by recycling the nutrients from dead tissues and wastes back into the ecosystem

gross primary productivity; GPP

the process in which scientists look at the total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time

net primary productivity; NPP

the energy captured minus the energy respired by producers

biomass

the total mass of all living matter in a specific area

standing crop

the amount of biomass present in an ecosystem at a particular time

ecological efficiency

the proportion of consumed energy that can be passed from one trophic level to another

trophic pyramid

represents the distribution of biomass along trophic levels

biosphere

the region of our planet where life resides

biogeochemical cycles

the movement of matter within and between ecosystems

macronutrients

six key elements that organisms need in relatively large amounts

limiting nutrient

a nutrient an organism needs because a lack of it results in constrained growth

disturbance

an event caused by a physical, chemical, or biological agents that result in changes in population size or community composition

watershed

all of the land in a given landscape that drains into a particular stream, river, lake, or wetland

resistance

a measure of how much a disturbance can affect the flows of energy and matter

resilience

the rate at which an ecosystem returns to its original state after a disturbance

restoration ecology

field of science that focuses on studying restoring damaged ecosystems

intermediate disturbance hypothesis

states that ecosystems experiencing intermediate levels of disturbance are more divers than those with high or low disturbance levels

instrumental value

a species that have worth as a tool that can be used to accomplish a goal

intrinsic value

species that have worth independent of any benefit it may provide to humans

provisions

goods that humans can use directly

biological diversity or biodiversity

the variety of the earth's species, the genes they contain, the ecosystems in which they live, and the ecosystem processes such as energy flow and nutrient cycling that sustain all life

vital renewable resource

species diversity

number of different species a community contains combined with the relative abundance of individuals within each of those species

genetic diversity

variety of genetic material within a species or population

ecosystem biodiversity

variety of terrestrial and aquatic ecosystems found in an area or on the earth

functional biodiversity

the biological and chemical processes such as energy flow and matter recycling needed for the survival of species communities, and ecosystems

biological evolution

the process whereby earth's life changes over time through changes in the genes of populations

natural selection

mechanism for biological evolution

occurs when some individuals of a population have genetically based traits that enhance their ability to survive and produce offspring with the same traits