Ecology and ecosystem Flashcards
What is the definition of ecology?
the study of interactions between organisms and their environment
what is the definition of ecosystem?
a dynamic interacting system formed by the communities of plants and animals in any one area together with their non-living environment
what is the definition of equillibrium?
a dynamic state of an ecosystem where biodiversity remains roughly constant, despite changes in species numbers and occurence
What are abiotic components? provide example.
non- living factors in the environment that interact with an organism
E.g. degree of solar energy (heat and light),
amount of rainfall and humidity, chemical
concentrations (e.g. C or N in soil), temp.,
seasonality
What is the definition of food chain?
linear sequence of organisms through which nutrients and energy pass as one organism eats another
what is the definition of levels on foodchain?
producers (lowest)< primary consumers < higher level consumers
what is the definition of producers?
photosynthetic organism
what is the definition of primary consumers?
organisms that consume the producers eat plants
what is the definition of secondary consumers?
carnivores that eat the primary consumers
what is the definition of tertiary consumers?
carnivores that eat other carnivores
what is the definition of apex consumers?
organisms at the top of the food chain in an organism
what is the definition of consumers?
use organic substances for growth and reproduction
- obtain all nutrients from plants (can’t make their
own from inorganic materials)
what is the definition of decomposers?
feeds on dead plants/animals
- break down plants and animals into simpler components and return nutrients to the environment to be used by plants
what is the definition of food web?
more appropriate for describing ecosystems when one organism can occupy multiple trophic levels
examples
e.g. an omnivore (bear/
squirrel), which is both a
primary and secondary
consumer
what is the definition of species richness?
describes the number of species living in a habitat or other unit (varies across the globe)
what is the definition of foundation species?
have the greatest influence on communitys overall structure. Are often primary producers and abundant.
Examples:
E.g. kelp (brown algae) is foundation species
for kelp forests off coast of California
* E.g. corals of a coral reef
what is the definition of relative species abundance?
the number individuals in a species relative to the total number of individuals in all species within a system
- usually have the highest relative abundance of species
what is the definition of keystone species?
has great influence in maintaining the species richness, structure and biodiversity in an ecosystem
examples:
E.g. banded tetra fish in tropical streams
* supply nearly all of the phosphorus (necessary
mineral) to rest of community
* Feeds on terrestrial insects and then excretes
phosphorus into the aquatic ecosystem
* Ecosystem would drastically change if fish
didn’t do this
what is the definition of invasive species?
non-native organisms that, when introduced to an area out of its native range, alter the community they invade
what is the difference between autotrophs and heterotrophs?
AUTOTROPHS: harness light or chemical energy
HETEROTROPHS: acquire energy through the consumption and digestion of other living or previously living organisms
Use organic substances for growth and
reproduction
* Obtain all nutrients from plants (directly or
indirectly)
* Primary consumers: feed directly on plants (e.g.
insects)
* Secondary and tertiary consumers: feed on animals
* Decomposers like fungi and bacteria
* Feed on dead plants and animals
* Break down plants and animals into
simpler components and return nutrients
to the environment to be used by
autotrophs (plants)
what is the definition of photoautotrophs
use sunlight as an energy source
what is the definition of chemoautotrophs
use inorganic molecules as an energy source
- found in rare ecosystem where sunlight not available, such as dark caves or hydrothermal vents at ocean bottom
- some convert hydrogen sulfide (H2S) to glucose
what are three types of interactions
-abiotic and producers
- between trophic levels
- among trophic level
what is abiotic and producers?
biotic component interact with and can alter physical environment
what is between trophic levels?
organisms at different feeding levels (e.g predator and prey relationships)
what is among trophic level?
between animals occupying same trophic levels (e.g. interspecific competition for same food)
what is the definition of neutralism?
neither species is affected by the interaction
- hard to measure since hard to know that there is absolutely no affect on one of species
what is the definition of competition?
each population adversely affects the other for struggle for food/ resources
- competition between species might limit each species population growth rate and size
- one species may drive other to extinction
example:
E.g. two Paramecium species who use the
same resources in the same habitat
what is the definition of symbiotic relationship?
close, long term interactions between individuals of different species
- can be commensal, mutualistic or parasitic
what is the definition of commensalism?
association in which one organism benefits and the other is not affected
Example: birds nesting in trees
what is the definition of mutualism?
obligatory relationship between two species that benefits both
- usually neither species can survive without the other
Examples: E.g. termites have protists in their gut
* Termites need protists to digest cellulose
* Protists need gut environment of termites for
protection and nutrition
E.g. lichen: a mutualistic relationship between
fungus and algae
* Algae produces food for both organisms
through photosynthesis
* Fungus protects algae from environment
what is the definition of parasitism?
One organism feeds off another
- one species is harmed and the other benefits
- parasite weakens but does not immediately kill the organism it preys on
- host usually kept alive until parasite completes reproductive cycle
examples:
E.g. Tapeworm: spread to humans through
undercooked pork, fish, or beef
* Can live inside human intestines for years, eating
host’s food
* Can grow up to 50 feet long
E.g. malaria protist (Plasmodium falciparum)
* lives inside human liver and red blood cells
* Needs to travel between hosts to complete life
cycle
* Reproduces asexually in human host and
sexually in gut of blood-feeding mosquitos
what is the definition of protocooperation?
both organism benefit from the interaction, but the relationship is not obligator
what is the definition of amensalism?
association in which one organism is inhibited and the other is not affected
example: red tide: fresh water algae
(phytoplankton) accumulate and sometimes
produce natural toxins which harm fish, birds,
and marine mammals
what is the definition of predation?
individuals of one species consume and kill individuals of another
- one organism benefits and the other does not
- population sizes of each species are not constant, but vary in cycles
what is the definition of mechanical defense?
presence of armor in animals of thorns in plants
- discourages predation and herbivory by discouraging physical contact
what is the definition of chemical defense?
some plants produce secondary compounds which serve no function except to be toxic to animals
- discourages consumption by animals
what is the definition of warning colouration?
some animals have bright colouration to advertise that they are poisonous and discourage predatory attack
- only works for predators that use eyesight to locate prey
- predators eat one toxic prey item, then learn to avoid similarly-coloured prey
what is the definition of mimicry
a harmless species imitates the warning coloration of a harmful species
- some prey species have evolved mechanisms to mimic warning coloration to avoid being eaten even though they are not toxic
* Sometimes multiple species
share the same warning
coloration, but all of them
have defenses
* Using the same signal better
alerts predators
* E.g. variety of toxic butterflies
have similar colouration
what is the definition of ecological niche?
functional position of an organism in its environment
- where an organism lives in an environment and what it does there
- role organism plays in an ecosystem
- sum total of the adaptations of an organism
* E.g. aye-aye (lemur in Madagascar)
* Lemurs fill many different niches on the island by
evolving some unique adaptations
* Aye-aye evolved features to help it locate and
extract insect larvae from tree branches
* Fills woodpecker niche in its environment
* fills niche due to morphological (body)
adaptations
what is competitive exclusion principle?
two species cannot occupy the same niche in a habitat
- based on competition between species
- different species cannot coexist in a community if they are competing for all the same resources
- resources are limited, so if species are competing for the same resource, the one that is most sucessful will drive the other to extinction
- traits that lessen dependence on shared resource will be selected for -species differentiation will reduce competition
E.g. two protozoan Paramecium species
* Both thrive when grown separately in laboratory
* When placed together in same test tube, P.
aurelia outcompetes P. caudatum for food
* P. caudatum dies out
what is community dynamics?
communities change in structure and composition over time
- changes caused by environmental disturbances like volcanoes, earthqueakes, storms, fires and climate change
what is the definition of succession?
sequential appearance and disappearance of species in a community over time after a severe disturbance
what is the definition of primary succession?
newly exposed/formed rock is colonized by living organisms
- E.g. new land is formed following volcanic
eruptions in Hawaii - As lava cools, new land is formed instead of
ocean - Natural forces break down rock enough for first
hardy species to grow
what is the definition of pioneer species?
the first species to colonize new land
- E.g. lichens and some plants on volcanic soil
- Help break down mineral-rich lava into soil
where less hardy species can grow - Grass, trees, shrubs will eventually replace
pioneer species
what is the definition of secondary succession?
ecosystem changes in response to environmental disturbances
- E.g. a fire destroys a forest
- Fire burns most vegetation, but nutrients return
to the ground as ash - Community is dramatically altered, but rich soil
allows rapid recolonization
what is different world vegetation zones?
- species adapted to live in different ecozones of world
- necessary due to difference in temperature, rainfall, altitude and vegetation in different world region
what is the definition of tropics?
+/- 23 degrees from the equator
Sun is directly overhead; constant warm
temperatures through year
* Wet and dry seasons; not fall/winter/etc.
* Usually very humid
* Days and nights each last about 12 hrs throughout
year
madgascar, costa rica, brazil
what is the definition of temperate
+/- 50 degree from the tropics of cancer and capricorn
Ontario, arizona, france, china
what is the definition of frigid?
+/- 66 degrees from equator also called polar region
northern canada, greenland, anartical, finland
What is the definition of biome
a group of natural communites that are broadly similar in plants, animals and climate
Can be terrestrial or aquatic
* Determined by temperature, rainfall, and altitude
* abiotic forces determine the major vegetation
types in a given area
what are the 8 terrestial biome?
-tropical forest
-boreal forest
- savanna
- tundra
-desert
-chapparal
what are the two aquatic biomes
- marines
- freshwater
what is the difference of species diversity and species richness?
SPECIES DIVERSITY: high number of species and high relative abundance
SPECIES RICHNESS: number of species
tropical rainforest
-vegetation is characterized by plants with spreading roots and broad leaves that fall off throughout the year
- constant daily amount of sunlight (11-12 hrs/day) provides more solar radiation and a longer period of time for plant growth
- high net primary productivity because the annual temperatures and precipitation values support rapid plant growth
* have a dry season of 3-5 months
* forests shed leaves during dry season
* loss of leaves allows sunlight to reach forest
floor and growth of thick ground-level brush,
which is absent in tropical rainforests
How to avoid competition?
animals adapted to live in different ecological niches of same TRF environment
Boreal forest
- found between 50-60 latitude
- predominant vegetation is evergreen coniferous trees
- retain needle-shaped leaves year-round
- Long, cold winters lead to predominance of
cold-tolerant, cone-bearing plants - cold, dry winters and short, cool, wet
summers - Soil is acidic
- Precipitation usually occurs as snow
- Less species diversity than in tropical forest
and temperate forest - Evergreen trees grow faster than deciduous
trees in the boreal forest - Slow-growing, long-lived trees
- E.g. Canada, Russia, Alaska, Northern Europe
Temperate forest
- most common biome in eastern North
America, Western Europe, Eastern Asia, Chile,
and New Zealand - Temperatures range -30C to 30C and drop
below freezing on an annual basis - defined growing seasons during spring,
summer, and fall - Deciduous trees are the dominant plant with
fewer evergreen conifers - Deciduous trees lose leaves in fall and remain
leafless in winter; new leaves appear in spring
as temperature increases - Constant rainfall through year
- Far less species diversity and richness than
tropical forests - Soil rich in organic and inorganic nutrients
Temperate grassland
- Hot summer and cold winters
- Specific growing seasons for plants: spring,
summer, and fall - Mostly grasses with few trees
- Dense vegetation and fertile soil
- E.g. North America and Eurasia
Terrestial biome
- Very dry summers with most plants dormant
- Majority of rain falls in winter
- Mostly shrubs grow
- Periodic fires
- Plants germinate after
fire: ash helps them grow - E.g. California, Australia
- Savanna: Grasslands with scattered trees
- Much lower species richness than tropical
forests - Hot, tropical areas with an extensive dry
season - Lots of fires
- Fire is important source of disturbance in this
biome - plants evolved well-developed root systems
that allow them to quickly re-sprout after a
fire - E.g. Africa, South America, Australia
- Desert: Very low precipitation levels
- Unpredictable rainfall levels annually with
little monthly variation - low species diversity due to low and
unpredictable precipitation - E.g. Sahara desert (Africa), Gobi (Asia)
- Tropical deserts have high of 60C during day
and low of 0C at night - Temperature cools so much due to lack of
water vapour in air - desert species are uniquely adapted to harsh
environment - E.g. Seeds can lie dormant for long times
between rains - E.g. animals are nocturnal and hide
underground during high daytime
temperatures - E.g. plants are annuals (live only for 1 season)
that grow quickly and reproduce when rainfall
occurs, then they die
Tundra
Located throughout Arctic regions of
northern hemisphere
* E.g. Canada, Alaska, Russia, Greenland, Europe
* Plants have short growing season of 50-60
days, but 24h of daylight during this time, so
plant growth is rapid
* Little species diversity
* Plants low to ground
* Permafrost: soil remains in a perennially
frozen state
* Soil melts a little in summer, but permafrost
prevents roots from penetrating far into the
soil
Marine biome
continuous body of salt water
* Oceans may be thought of as different zones
based on water depth, distance from
shoreline, and light penetrance
* E.g. ocean, estuary (coastal – fresh and salt
water mix), coral reef
* Most common biome on earth’s surface
* Covers 75% of earth
* 3 basic types: shallow ocean, deep ocean water,
deep ocean bottom
* Deep ocean bottom:
* ecosystems exist even
at depths where light is
unable to penetrate
through the water
* Least biodiversity
within marine biome
Freshwater biome
water is fresh – lacks salt
* Part of a terrestrial landscape
* E.g. lakes, ponds, rivers, streams, wetlands
* Freshwater ecosystems are least common
biomes - cover only 1.8% of Earth
* Freshwater systems are diverse
* support many different animals, plants, fungi,
protists and prokaryotes
