Ecology Flashcards
ecology
the study of interactions between organisms and their environment.
environment
encompasses all that is external to the organisms and is necessary for its existence.
-contains two components- the physical or non living and the living environment.
physical environment
climate, temperature, availability of light and water and the local topology
the biotic environment
includes all living things that directly or indirectly influence the life of the organism, including the relationships that exist between organisms.
Organism
the individual unit of an ecological system but the organism itself if composed of smaller units.
-contains many organ systems which are made up of organs->, tissues->, cells and many different molecules->atoms ->subatomic particles
population
a group of organisms of the same species living together in a given location.
species
any group of similar organisms that are capable of reproducing fertile offspring.
communities
consists of populations of different plants and animals species interacting with each other in a given environment.
-generally a community contains populations from all five kingdoms depending on each other for survival
biotic community
used to include only the populations and not their physical environment
ecosystem
ecological community- encompasses the interaction between living biotic communities and the nonliving environment.
biosphere
includes all portions of the planet that support life- the atmosphere, the lithosphere (rock and soil surface) and the hydrosphere (oceans). its is relatively thin zone extending a few feet beneath the earths surface, several miles into the deepest sea and several miles into the atmosphere
Water
water is the major component of the internal environment of all living things. water may be readily available, or the organism may posse adaptations for storage and conversion of water.
temperature
temperature must be maintained at an optimal level. organisms have adaptations necessary for protection against extremes.
temperature in a location depends on the geographic latitude and altitude.
sunlight
the ultimate source of energy for all organisms. green plants must compete for sunlight in the forests. but they have multiple adaptations
photic zone
in water is the top layer through which light can penetrate and where all aquatic photosynthetic activity takes place
aphotic zone
only animal life and other heterotrphic life exists
oxygen supply
poses no problem in terrestrial life since the air contains 20% of oxygen.
aquatic plants and animals utilize the small amount of oxygen dissolved in water.
pollution in water
significantly lower oxygen content in the water and threatening aquatic life.
Substratum
the substratum determines the nature of plant and animal life in the soil. Soil is affected by ; acidity, texture minerals and humus.
acidity of soil
rhododendrons and pines are more suited for growth in acidic soil. acid ran may make soil pH too low for plant growth
texture of soil
and its clay content determine the water holding capacity of the soil. most plants grow well in loams, which contain high percentages of each type of soil
minerals in soil
including nitrates and phosphates affect the type of vegetation that can be supported. beach sand has no minerals
humus in soil
the quantity is determined by the amount of decaying plant and animal life in the soil
niche
defines the functional role of an organism in its ecosystem.
describes what the organism eats, where and how it obtains food, what climatic factors it can tolerate and which are optimal, etc. it embodies every aspect of the organisms existence
-very specific -no two species can have the same niche in the same location.
habitat
physical place where an organism lives. the characteristics of the habitat aid in defining the niche.
Competition
when species occupying similar niches utilize at least one resource in common. leads to extinction, elimination, divergent developing differences in their niches
autotrophs
organisms that manufacture their own food
heterotrophs
cannot synthesize their own food and must depend upon autotrophs or other heterotrophs in the ecosystem to obtain food and energy
herbivores
animals that only consume plants or plant foods. the toughness of cellulose containg plant tissues has led to the development of parts for grinding and crushing. also having long digestive systems with symbiotic bacteria to assist in digestions.
more defensive because they are often prey.
carnivores
animals that only eat other animals. they posses pointed fanglike teeth for tearing flesh. they have shorter tracts due to easier digest animal food.
omnivores
animals that eat both plants and animals.
major types of interspecific interactions
symbiosis, predation, saprophytism, and scavenging.
symbiosis
symbionts live together in an intimate often permanent association which may or may not be beneficial to both participants.
-some are obligatory: one cant survive w/o the other
types of relationships are commensalism, mutualism, parasitism
commensalism
one organism is benefited by the association and the other is not affected. the host neither discourages nor fosters the relation ship.
(+/0)
mutualism
(+/+) a symbiotic relationship from which both organisms derive some benefit
parasitism
a parasite benefits at the expense of the host. exists when competition for food is most intense. few autotrophs are parasite. Seen mostly in bacteria fungi and animals.
-does not kill the host because if so then it will die.
ectoparasites
cling to the exterior surface of the host using suckers or clamps
endoparasites
live within the host. to gain entry they must pass through defenses like skin, digestive juices antibodies and WBC.
predation
free living organisms that feed on other living organisms. includes both carnivores and herbivores. in many cases the predator aids in controlling the number of the prey but not so much as to endanger the existence of the prey population.
saprophytism
include those protists and fungi that decompose dead organic matter externally and absorb the nutrients: they constitute a vital link in the cycling of material within the ecosystem.
scavengers
are animals that consume dead animals. they don’t have any adaptations for hunting and killing their prey. decomposes can be considered scavengers.
intraspecific interaction
species may also compete with one another for resources. but they must also cooperate. it can be extensive or nearly non existent. influenced by disruptive and cohesive forces. disruptive is competitions and cohesive include reproduction and protection.
osmoregulation
animals have developed many adaptations for maintiang their internal osmolarity and conserving water
salt water fish water reg
live in an hyperosmotic environment which causes them to loose water and take in salt. they must compensate by constant drinking of water and excretion of salt across their gills
fresh water fish water reg
live in a hypo-osmotic environment which causes intake of excess water and excessive salt loss. they drink seldom and absorb salts through the gills and excreting dilute urine
insects water reg
excrete solid uric acid crystals to conserve water
desert animals water reg
- the camel can tolerate a wide rang of body temps and fat layers assist
- horned toad thick scaly skin to prevent water loss
- others avoid sunlight
plants water reg
- non desert plants have waxy cuticles on leaf surfaces and stomata on the lower leaf surface. they shed leaves in the winter to avoid water loss.
- desert plants have extensive root systems and fleshy stems to store water. spiny leaves to limit water loss
thermoregulation
60% of total energy is given off as heat. vast majority of animals and plants are cold blooded or poikilothermic, most of the energy escapes to the environment.
poikilotherms
body temp is very close to that of its environment. since the metabolism is closely related to its surroundings temp, it is radically effected by environmental changes.
homeothermic
mammals and birds. evolved physical mechanisms that allow them to make use of heat produced as consequence of respiration. the temp maintained is that higher then the environment expanding their capabilities
Energy flow
transfer of energy mapped out in a food chain or food web each ecosystem has one
Food chain
single chain showing the transfer of energy . within the food chain energy is transferred from the original source in green plants through a series of organisms in repeated stages of consumption and decomposition.
there are producers, primary consumers, secondary and decomposers
producers
autotrophic green plants and chemo synthetic bacteria are the producers. they utilize the energy of the sun and simple raw materials (CO2, water and minerals) to manufacture carbs lipids and proteins.
primary consumers
animals that consume green plants (herbivores)
secondary consumers
animals that consume the primary consumers (carnivores)
tertiary consumers
animals that feed on secondary consumers (also carnivores)
decomposers
include the saprophytic organisms and organisms of decay which include bacteria and fungi.
food web
is not a simple linear chain but an intricate collection of interconnected food chains. there are diff food chain levels which are consumed by other food chains. the greater number of pathways that the food chain connects the more stable the community
food pyramids of energy
each member of the food chain utilizes some of the energy it obtains for its food for its own metabolism. and looses some addtional energy in the form of heat. leading to a loss of energy at every feeding level
pyramid of mass
since organisms at the upper levels of the food chain derive their food energy form the lower levels, and energy is lost from one level to the next- each level can support a successively smaller biomass. 100g of grass->20lbs of grass hoppers etc
pyramid of numbers
consumer organisms at the top of the food chain are normally larger and usually heavier than those further down. and the mass equates to the population.
Material cycles
material is cycled and recycled between organisms and their environment. passing forms of inorganic to organic then back to inorganic. credited largely to decomposers and scavengers
Nitrogen cycle
elemental nitrogen cannot be used by organisms. Lighting and nitrogen fixing bacteria in the roots of legumes change nitrogen to usable nitrates
- nitrates are absorbed by plants and are used to synthesize nucleic acids and plant proteins.
- animals eat the plants synthesize their own materials then die and give off wastes.
- nitrogen locked up in the wastes and dead tissues are released by bacteria decay which converts proteins into ammonia.
fates of ammonia in nitrogen cycle
- some is nitrified to nitrites by chemosynthetic bacteria then to usable nitrates by nitrifying bacteria
- rest is denitrified
denitrifed
ammonia is broken down to release free nitrogen which returns it to the beginning of the nitrogen cycle
carbon cycle
- gaseous CO2 enters the living world when plants use it to produce glucose via photosynthesis.
- animals eat the plants and use nutrients to form carbs, fats and proteins. a part of these are used as fuel in respiration in plants and animals
- metabolic produced CO2 is released in the air the rest is release after the being is decomposed.
conditions for stability in the ecosystem
self sustaining and will remain if it has relatively stable physical environment and community, constant energy source and living system to transfer energy, and cycling of materials.
ecological succession
the orderly process by which one biotic community replaces or succeeds the other until a climax community is established.
-each community stage or sere in an ecological succession is identified by a dominant species- the one that exerts control over the other species that are present.
grass in the grasslands
why do changes occur
because each community that establishes itself changes the environment, making it more favorable for itself and for its community that succeed it
climax community
the final and most stable stage of succession that occurs after the replacement of a new community that was created. permanent unless there is drastic change in equilibrium
pioneer organism
base and producer of the new community- if it has the proper resources and physical factors it will thrive
terrestrial biomes
desert, grassland, tropical rain forest, temperate deciduous forest, temperate coniferous forest, taiga, tundra and polar regions.
biome
geographic region inhabited by a distinct community
Land biome characterization
according to the climax vegetation of the region.
climax vegetation
the vegetation that becomes dominant and stable after years of evolutionary development. and since plants are the primary producers they in turn determine the climax animal population
Desert biome
receive fewer than 10 inches of rain a year
- growing is restricted to after the short burst of rain falls
- inhabited by small plants and animals
- desert plants conserve water, animals live in burrows yet few mammals and birds live here
grassland biome
low rain fall 10-30 inches a year
- provide no shelter for herbivorous animals from predators
- animals here have long legs and hooves for protection
- deer ox etc
Tropical rain forest biome
Jungles- with high temps and torrential rains
- dense growth of vegetation that does not shed leaves.
- saprophytes live on the floor of the forest
- monkeys, lizards insects ex.
temperate deciduous forest biome
- cold winters, warm summers and moderate rainfall
- trees such as beech, maple and oaks and willow shed their leaves during cold winter months
- deer, fox and squirrels etc
temperate coniferous forest biome
cold, dry and inhabited by fir, pine and spruce trees. much of the vegetation has evolved adaptations for water conservation, such as needle shaped leaves.
taiga biome
receive less rainfall than the temperate forest
- long cold winters and are inhabited by a single coniferous tree the spruce.
- floor contains moss and lichens
- moose is chief then bears and wolves etc
polar region
frozen with no vegetation, and few terrestrial animals. few that do live there live near the polar oceans.
tundra biome
treeless, frozen plain found between the taiga lands and northern ice sheets. very short summer and short growing season.
-lichens, moss polar bears and arctic hens
aquatic biomes
more than 70% of the earths surface is covered by water. 90% of the earths food and oxygen production takes place in the water.
- most stable ecosystems the food systems are balanced
- marine and freshwater
marine biome
composed of the oceans, form to connect one continuous body of water. which controls the earths temp by absorbing solar heat. contains relatively constant amount of nutrient materials and dissolved salts.
intertidal zone
the region of the ocean exposed at low tides that undergoes variations in temp and periods of dryness. populations are of algae, sponges, clams, snails sea urchins and crabs
littoral zone
the region on the continental shelf that contains ocean area with depths up to 600 feet and extends several hundred miles from shores.
population- algae crabs crustacea and many diff fish
pelagic zone
typical of the open seas and can be divided into photic and aphotic zones.
photic zone
the sunlit layer of the open sea extending to ta depth of 250-600 feet. contains plankton, nekton, the chief autotroph is diatom an algae
plankton
passively drifting masses of microscopic photosynthetic and heterotrophic organisms
nekton
active swimmers such as fish sharks or whales
Fresh water biomes
rivers, lakes ponds and marshes the links between oceans and land.
factors that effect life are temp, transparency, depth of water, available carbon dioxide and oxygen and salt concentration.
rivers
routes by which ancient marine organisms reached land and evolved terrestrial adaptations. many failed to adapt and can cope with land and water
how freshwater differs from salt water
- hypotonic- plants and animals have adapted to ways to remove excess water
- river and streams have strong swift currents thus selection favored fish and plants with strong muscles and roots
- temp varies
