ecology
the science of how organisms interact with one another and with their nonliving environment of matter and energy.
greenhouse effect
natural effect is vital to life on Earth. tropospheric greenhouse gases have a large capacity for heat.
autotrophs
organisms such as plants that make their own food. primary producers. use light or chemical energy to synthesize organic molecules.
chemosynthesis
a few producers, mostly specialized bacteria, can convert simple inorganic compounds from their environment into more complex nutrient compounds without the use of sunlight.
heterotrophs
cannot obtain energy directly from the sun, instead from the food they eat.
decomposers
specialized organisms that recycle nutrients in ecosystems
10% rule
10% energy is lost at each subsequently higher trophic level.
biomass
dry weight of all organic matter contained in its organisms
ecosystem
a biological community where populations of different species interact with one another and the abiotic factors in their environment
interdependence
all life is connected
biodiversity
a variety of life is important to genetics, species development, food webs, social structure and beauty
limiting factors
there is a limit to the amount of change in abiotic factors that an organism can tolerate
unpredictability
Earth is dynamic; ecosystems are prone to change in different ways
resilience
ability to recover from disaster
recycling
continual reuse of matter
adaptability
ability of populations to change or evolve in response to the environment
species richnesss
the total number of different species in the community
relative abundance
the proportion each species represents of the total individuals in the community
Shannon-Weiner Diversity Index
the measure of the order/disorder in a particular community. order is characterized by the number of individuals found for each species/category in a sample.
ranges of tolerance
different levels of abiotic and biotic factors under which populations can survive. the larger the range of tolerance for a species, the larger variety of habitats it can live in.
local extinction
species no longer found in an area it once inhabited but is still found elsewhere in the world
ecological extinction
so few members remain that the species cannot maintain its ecological role, or members only survive in captivity
biological extinction
literally no members left. irreversible.
endangered species
species that have so few individual survivors that extinction is a real possibility and survival is not certain
threatened species
still abundant in their natural habitats but are likely to become endangered due to declining numbers
characteristics of endangered species
low reproductive rate, specialized niche, narrow distribution, feeds at high trophic levels, fixed migratory patterns, rare, commercially valuable, large territory
biological hot spots
areas with much higher than global average of biodiversity and also much higher extinction rates. Tropical forests, coral reefs, wetlands, estuaries
causes of premature extinction (HIPPO)
Habitat destruction, Invasive species, Population growth (human), Pollution, Overharvest
habitat island
any habitat surrounded by a different one
habitat fragmentation
large, continuous area of habitat is reduced in area and divided into smaller, more scattered and isolated patches or "habitat islands
invasive species
non-native species that are either accidentally or deliberately introduced into an area that cause harm to the native (endemic) species. have no natural predators, no competition, no parasites or pathogens
ecological niche
a species' way of life or role in the community or ecosystem
specialist species
narrow niches. may be able to live in only one type of habitat, eat a few types of food, or have a narrow range of tolerance to environmental conditions.
generalist species
broad niches. can live in a wide variety of habitats and eat a wide variety of foods; wide range of tolerance to environmental conditions
keystone species
help determine the types and numbers of other species in the community. important roles in sustaining ecological communities.
pollinators
insects, hummingbirds, and bats pollinate the plant species, allowing reproductive cycle to continue
mangrove trees
many species are called this; their seeds disperse in saltwater and take root to form a dense forest in saltwater shallows, providing a variety of habitats.
grizzly bears
serve as ecosystem engineers by transferring nutrients from oceanic to forest ecosystems
indicator species
serve as early warnings of environmental problems
birds
widely dispersed population, quickly affected by environmental change such as loss or fragmentation of habitat, or introduction of chemical pollutants and pesticides.
competition
two or more organisms "fight" for limited resources such as nutrients, living space or light
competitive exclusion principle
two species competing for the same limiting resources cannot coexist in the same niche. at least one of the species will be driven to extinction
resource partitioning
one of the species will evolve by natural selection to exploit different resources
character displacement
species diverge in body structure so they no longer compete for resources
predation
an interaction where one species, the predator, kills and eats the other, the prey
parasitism
symbiotic relationship where one organism, the parasite, derives its nourishment from another organism, its host, which is harmed in the process
mutualism
symbiotic relationship where both organisms benefit from the interaction
commensalism
symbiotic relationship where one organism benefits from the relationship and the other organism is unaffected
amensalism
the interaction between two species where one species suffers and the other is not affected
ecological succession
the sequence of gradual changes in species composition in a given area. ecosystems change in response to disturbances such as: fires, volcanic eruptions, climate change, and the clearing of forests to plant crops.
primary ecological succession
involves the gradual establishment of biotic communities in lifeless areas where there is no soil or bottom sediment. takes hundreds of thousands of years because of the need to build up fertile soil/aquatic sediments to provide the nutrients needed to es
secondary ecological succession
series of communities with different species develop in places containing soil or bottom sediment. soil or sediment is present, so new vegetation can begin to germinate within weeks.
classic view of ecological succession
succession is a gradual and orderly process of ecosystem development brought about by changes in community composition and the production of a climax community characteristic of a particular geographic region.
pioneer species
early successional species, generalists, short reproductive times (annuals). low biomass and fast reproductive rates
later successional species
larger perennial plants, animals with greater biomass, longer generational times, and higher parental care
current view of ecological succession
a given course cannot be predicted or viewed as an inevitable progress toward an ideally adapted climax community. succession reflects the ongoing struggle by different species for resources.
persistence
the ability of an ecosystem to survive moderate disturbances
resilience
the ability of a living system to be restored through secondary succession after a more severe disturbance
biomes
large terrestrial regions characterized by similar climate, geography, soil, plants, and animals
factors that influence biomes
average annual precipitation, average temperature, soil type, latitude, elevation
climatogram
graph that shows a biome's monthly temperature and precipitation in a single year.
desert biome
area where evaporation exceeds precipitation. three types: tropical, temperate, polar
grassland and chaparral biomes
seasonal droughts, grazing by large herbivores, occasional fires.
savanna
warm temperatures year-round, alternating wet and dry seasons, widely-spaced trees
prairie
seasonal rainfall, dependent on seasonal fires, fertile soil
temperate shrublands
slightly longer winter rainy season than temperate desert, consist of dense growth of low-growing evergreen shrubs and occasional small trees. highly susceptible to fires
forest biomes
tree species specific to their climate, along with smaller plant species and numerous animal species
tropical rain forests
year-round warm temperatures, high humidity, heavy rainfall, ecosystems within this biome are extremely diverse.
temperate deciduous forests
significant seasonal temperature change, long, warm summer and cold winters, abundant precipitation
boreal forests/taiga
long, dry, cold winters, 6-8 hours of sunlight per day, short summers
saltwater
includes estuaries, coastlines, coral reefs, open ocean, deep ocean
freshwater
lakes, ponds, streams, rivers, inland wetlands
solar energy
determines amount of photosynthesis (primary productivity)
temperature
directly affects dissolved oxygen; colder water can hold more DO
dissolved oxygen
from photosynthetic organisms and surface mixing, affected by many other factors: salinity, temperature, vegetation and bacteria
salinity
saltier water can hold less DO. saltier water is denser and heavier, so mixing is prevented (important in estuaries)
pH
saltier water has higher pH- estuaries about 7.5; ocean water about 8.1
euphotic or limnetic zone
photosynthesis largely confined to this upper layer in marine or freshwater systems
intertidal zones
area of shoreline between low and high tides. organisms living in this zone must be able to avoid being swept away or crushed by waves. must also survive changing levels of salinity and temperature.
coral reefs
amazing centers of aquatic biodiversity; one of world's oldest, most diverse, and productive ecosystems
bathyal zone
dimly lit middle zone. no photosynthesis due to lack of sunlight
abyssal zone
dark, very cold, little dissolved oxygen. large number of specially adapted species. high pressure.
hadal zone
ocean trenches
estuaries
where rivers meet the sea.
coastal wetlands
land areas covered with water all or part of the year.
coastal ecosystems
low plant diversity, species must be able to withstand the daily and seasonal variations. high primary productivity and biodiversity. reduce flooding and erosion
mangrove forests
help maintain water quality by filtering toxic pollutants, excess plant nutrients, and sediments
oligotrophic lakes
poorly nourished lakes (small supply of plant nutrients)
eutrophic lakes
well nourished lakes (large supply of nutrients needed by producers)
thermocline
boundary between warm and cold zones in a lake/pond. swithces with the seasons and causes important nutrients to be mixed in the water.