Ecology and ecosystem

Question 1

What is the definition of ecology?

Answer 1

the study of interactions between organisms and their environment

Question 2

what is the definition of ecosystem?

Answer 2

a dynamic interacting system formed by the communities of plants and animals in any one area together with their non-living environment

Question 3

what is the definition of equillibrium?

Answer 3

a dynamic state of an ecosystem where biodiversity remains roughly constant, despite changes in species numbers and occurence

Question 4

What are abiotic components? provide example.

Answer 4

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

Question 5

What is the definition of food chain?

Answer 5

linear sequence of organisms through which nutrients and energy pass as one organism eats another

Question 6

what is the definition of levels on foodchain?

Answer 6

producers (lowest)< primary consumers < higher level consumers

Question 7

what is the definition of producers?

Answer 7

photosynthetic organism

Question 8

what is the definition of primary consumers?

Answer 8

organisms that consume the producers eat plants

Question 9

what is the definition of secondary consumers?

Answer 9

carnivores that eat the primary consumers

Question 10

what is the definition of tertiary consumers?

Answer 10

carnivores that eat other carnivores

Question 11

what is the definition of apex consumers?

Answer 11

organisms at the top of the food chain in an organism

Question 12

what is the definition of consumers?

Answer 12

use organic substances for growth and reproduction
- obtain all nutrients from plants (can’t make their
own from inorganic materials)

Question 13

what is the definition of decomposers?

Answer 13

feeds on dead plants/animals
- break down plants and animals into simpler components and return nutrients to the environment to be used by plants

Question 14

what is the definition of food web?

Answer 14

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

Question 15

what is the definition of species richness?

Answer 15

describes the number of species living in a habitat or other unit (varies across the globe)

Question 16

what is the definition of foundation species?

Answer 16

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

Question 17

what is the definition of relative species abundance?

Answer 17

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

Question 18

what is the definition of keystone species?

Answer 18

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

Question 19

what is the definition of invasive species?

Answer 19

non-native organisms that, when introduced to an area out of its native range, alter the community they invade

Question 20

what is the difference between autotrophs and heterotrophs?

Answer 20

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)

Question 21

what is the definition of photoautotrophs

Answer 21

use sunlight as an energy source

Question 22

what is the definition of chemoautotrophs

Answer 22

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

Question 23

what are three types of interactions

Answer 23

-abiotic and producers
- between trophic levels
- among trophic level

Question 24

what is abiotic and producers?

Answer 24

biotic component interact with and can alter physical environment

Question 25

what is between trophic levels?

Answer 25

organisms at different feeding levels (e.g predator and prey relationships)

Question 26

what is among trophic level?

Answer 26

between animals occupying same trophic levels (e.g. interspecific competition for same food)

Question 27

what is the definition of neutralism?

Answer 27

neither species is affected by the interaction - hard to measure since hard to know that there is absolutely no affect on one of species

Question 28

what is the definition of competition?

Answer 28

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

Question 29

what is the definition of symbiotic relationship?

Answer 29

close, long term interactions between individuals of different species - can be commensal, mutualistic or parasitic

Question 30

what is the definition of commensalism?

Answer 30

association in which one organism benefits and the other is not affected Example: birds nesting in trees

Question 31

what is the definition of mutualism?

Answer 31

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

Question 32

what is the definition of parasitism?

Answer 32

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

Question 33

what is the definition of protocooperation?

Answer 33

both organism benefit from the interaction, but the relationship is not obligator

Question 34

what is the definition of amensalism?

Answer 34

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

Question 35

what is the definition of predation?

Answer 35

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

Question 36

what is the definition of mechanical defense?

Answer 36

presence of armor in animals of thorns in plants - discourages predation and herbivory by discouraging physical contact

Question 37

what is the definition of chemical defense?

Answer 37

some plants produce secondary compounds which serve no function except to be toxic to animals - discourages consumption by animals

Question 38

what is the definition of warning colouration?

Answer 38

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

Question 39

what is the definition of mimicry

Answer 39

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

Question 40

what is the definition of ecological niche?

Answer 40

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

Question 41

what is competitive exclusion principle?

Answer 41

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

Question 42

what is community dynamics?

Answer 42

communities change in structure and composition over time - changes caused by environmental disturbances like volcanoes, earthqueakes, storms, fires and climate change

Question 43

what is the definition of succession?

Answer 43

sequential appearance and disappearance of species in a community over time after a severe disturbance

Question 44

what is the definition of primary succession?

Answer 44

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

Question 45

what is the definition of pioneer species?

Answer 45

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

Question 46

what is the definition of secondary succession?

Answer 46

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

Question 47

what is different world vegetation zones?

Answer 47

- species adapted to live in different ecozones of world - necessary due to difference in temperature, rainfall, altitude and vegetation in different world region

Question 48

what is the definition of tropics?

Answer 48

+/- 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

Question 49

what is the definition of temperate

Answer 49

+/- 50 degree from the tropics of cancer and capricorn Ontario, arizona, france, china

Question 50

what is the definition of frigid?

Answer 50

+/- 66 degrees from equator also called polar region northern canada, greenland, anartical, finland

Question 51

What is the definition of biome

Answer 51

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

Question 52

what are the 8 terrestial biome?

Answer 52

-tropical forest -boreal forest - savanna - tundra -desert -chapparal

Question 53

what are the two aquatic biomes

Answer 53

- marines - freshwater

Question 54

what is the difference of species diversity and species richness?

Answer 54

SPECIES DIVERSITY: high number of species and high relative abundance SPECIES RICHNESS: number of species

Question 55

tropical rainforest

Answer 55

-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

Question 56

How to avoid competition?

Answer 56

animals adapted to live in different ecological niches of same TRF environment

Question 57

Boreal forest

Answer 57

- 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

Question 58

Temperate forest

Answer 58

* 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

Question 59

Temperate grassland

Answer 59

* 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

Question 60

Terrestial biome

Answer 60

* 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

Question 61

Tundra

Answer 61

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

Question 62

Marine biome

Answer 62

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

Question 63

Freshwater biome

Answer 63

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