bio chap 19

Habitat

• the type of physical surroundings that a species inhabits

• widely separated populations of the same species generally inhabit the same __

• can support multiple species

Ecological niche

• the functional role and "lifestyle" of a species within an ecosystem, defining how it survives, reproduces, and interacts with biotic (living) and abiotic (non-living) factors.

• an organisms specialization, includes habitat, feeding habits, & other behaviors

• specific to one species

Biome

• a very large ecosystem characterized by a particular climate, vegetation, & group of species

• influenced by: precipitation & temperature

  • u can predict what kind of biological communities are likely to develop in an area knowing this

• ex. desert

Climate

• refers to the long-term patterns of weather in a particular region

• biome: determined by local __

  • temp & precipitation

• weather

  • local & short term

• earths __ determined by

  • axial tilt: 23.5

  • latitude

  • atmospheric circulation

  • prevailing winds

  • precipitation

  • ocean currents

  • local topography (mountains, hills, valleys, rivers)

ex.

• las vegas is a desert __ (36N)

  • latitude & atmospheric circulation

  • rain shadow effect of mountain ranges between us & ocean

Prevailing winds

• a surface wind that blows predominantly from a particular direction.

What is the Earths North-South axis tilited number (with respect to earths orbital plane)

23.5˚

Axial tilt

• causes the seasons

  • if it was 0 there would be none

• variations in the intensity of sunlight an area receives

• insolation: amount of sunlight per square foot an area receives (intensity of sunlight)

Insolation

• amount of sunlight per square foot an area receives (intensity of sunlight)

Latitude

• distance from the equator

• as move away from equator = climates become cooler

• helps determine climate

Equatorial regions

• low latitude

• higher insolation

• warmest

Polar latitudes

• high latitude

• lowest insolation

• coldest

Atmospheric circulation

• refers to the vertical & north-south motion of air (prevailing winds)

• coriolis effect: air moves east-west as a result of earths rotation

• tropics (trade winds)

• middle latitudes (westerlies): flow west to east

• impact climate based on arrival over ocean or land

  • ocean based (moisture)

How atmospheric circulation works

• warm air rises over cold

  • can hold more moisture

• large quantities of warm moist air rise from oceans at tropical latitudes

  • will cool as it rises

  • moisture lost as precipitation

  • reason why tropical areas are so wet

• cool air then moves north, away from equator

• 30 N latitude & 30 S latitude

  • air descends & is warmed

• air is warm & dry to absorb moisture from the environment

  • result = desert climates

• some of air that descended at 30 N moves north, absorbing moisture as it goes

• air rises again, release its moisture as precipitation around 60 N

• same thing happens in southern hemisphere

* pattern is not perfect bc of mountains & oceans

Why are tropical areas so wet

• intense solar radiation at the equator, which causes massive amounts of water to evaporate from oceans and land, forming, rising, and condensing into frequent, heavy rainstorms

Weather

• day to day state of the atmosphere at a place & time

• short term

Coriolis effect

• the apparent curving of the path of objects (like air or water) moving long distances over Earth’s surface, caused by the planet's rotation

• a phenomenon where the Earth's rotation causes moving objects (like air currents, planes, or ocean currents) to travel in a curve rather than a straight line

• bc the Earth spins faster at the equator than at the poles, objects moving long distances appear to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

• air moves east-west as a result of earths rotation

Ocean currents

• have an important effect on local climate

• warm currents = warmer local climate

• cold currents = colder local climate

Windward

• refers to the side facing the wind (upwind), experiencing colder, wetter, and stormier conditions

Leeward

• situated on or toward the side sheltered from the wind

• enjoying warmer, drier, and calmer weather

Topography

• the study and mapping of the land surface's physical features, including elevation, slopes, and shapes like mountains, valleys, and rivers

• rain shadow

• local __ dramatically impact local climate

  • 1. moist air blows in

  • 2. as the air rises, it cools & drops its moisture on the windward side of the mountains

  • the dry air descends on the leeward side of the mountains

Rain shadow

• a dry region on the leeward (downwind) side of a mountain range that experiences significantly reduced rainfall compared to the windward side

Vegetation

• determined by the local climate

Mountains

• contain a variety of biomes, depending on the altitude

Polar ice cap biomes

• forms at the poles, are the coldest & among the driest of earths biomes

• no month has an avg temp above freezing

• no vegetation

• all life found near ocean

  • food resource

    • polar bear eats seal

    • seal & penguins eat fish

    • worm & crustaceans apart of food web

    • primary producers: phytoplankton

    • inhabited by whales, seals, birds

• inland areas largely lifeless

Tundra biomes

• gives way to ice caps

• “treeless plain” biomes

• at least one month with an avg temp above freezing

• very cold, long winters

• dry

  • permafrost: deep ground frozen year round

    • prevents tree growth

• very marshy/swampy

  • water has nowhere to go

• plant life: mosses, lichen, grass, shrubs, mosses

• large herbivores: moose, reindeer

• carnivores: artic fox

• avg temp: below 0 C

• annual precipitation: 50 cm

Taiga (boreal forest) biomes

• found south of tundra biomes (gives way to tundra)

• extremely long dry cold winters

• short, cool summers

  • little/moderate rainfall

• a few species of conifers/ coniferous trees dominate

  • juniper, spruce, fir, pine

• animals: beavers, lynxes, hares, reindeer, wolves, bears,

• caribou, reindeer, lynx, spruce, firs, pines, migratory birds

Temperate deciduous forest biomes

• found in mid-latitude south of taiga (gives way to taiga)

• cold winters

• warm/hot summers

  • lots of rainfall

• mostly deciduous trees

  • oak & maple trees that shed their leaves seasonally

• have been largely destroyed

• support large variety of animal life

  • deer, squirrels, snakes, birds, foxes

• avg temp: 10 C

• annual precipitation: 100 - 200 cm

Temperate grassland biomes

• found in mid-latitude inland areas

• hot summers, cold winters

• less rainfall than temperate forests

  • transition to desert climate

• ecological dominants

  • grasses

• today = mostly farmland

• fertile soils support expanse of wind-pollinated grrasses that are home to unique herbivores, such as prairie dogs & chickens

• bisons used to live here

Chaparral biomes (mediterranean shrubland)

• occur on coasts

• mid-latitude west coasts have unique type of climate

  • mediterranean

  • hot rainless summer

  • cool wet winters

• dense evergreen shrubs, few trees

• transitions to desert climate away from coast

Desert biomes

• charaterized by very little rainfall & variable temperature

• mid-low latitudes (45 N or S to 15N or S)

• not hot all of the time

  • nortthern deserts have very cold winters

  • summer is hot

• support a large variety of organisms

• vegetation evolved to conserve water / are adapted to dry conditions

• animal life: hares, coyotes, snakes, birds, lizards

• avg temp: 0 C - 30 C

• annual precipitation: 0-100 cm

Tropical savanna biomes

• found in tropical areas (low latitudes)

• distinct wet & dry seasons

• hot year round

• grassland with sparse / scattered trees

• very muddy & green in wet season

• bone dry in dry season

  • large variety of animal life: elephants, zebras, giraffes, etc

Tropical rainforests

• found near the equator

• hot & wet climate year round (no real “seasons”)

• dense, permanent evergreen forest

• most abundant, productive & biodiverse biome on earth

  • diverse plant species include large trees

• avg temp: 25 C

• annual precipitation: 350 cm

Mountainous areas

• exhibit a wide variety of biomes

• precipitation & temp decrease as we move up, as they do when we move north

• as altitude increases, it is as if we moved towards the poles

% of salltwater (in oceans)

97%

% of freshwater

3%

% of water in ice caps & glaciers (freshwater)

2.06%

Marine biomes

• vary based on depth & distance from land

• depth (P.P.B)

  • Photic zone (surface)

  • Pelagic zone (deep water)

    • pitch black

  • Benthic zone (ocean bottom)

    • pitch black

• distance from land (I.C.O)

  • Intertidal zone (very productive)

  • Coastal zone (less productive)

  • Open sea (least productive)

  • photosynthesis decreases as move away from land & go deeper

Photic zone (ocean depths)

• surface

• where photosynthesis is possible

  • sufficient light

  • phytoplankton are dominant producers here

  • rooted plants thrive ere

Pelagic zone (ocean depths)

• deep waters

• pitch black

Benthic zone (ocean depths)

• ocean bottom

• esp pitch black

Intertidal zone (distance from land)

• where land & ocean meet

• frequently exposed to air and submerged by water.

• very productive

Coastal zone (distance from land)

• the interface between the land and water

• less productive

Open sea (distance from land)

• least productive

Phytoplankton

• main primary producers of marine biomes

• microscopic photosynthetic organisms that drift in water

• photosynthesizers

Zooplankton (krill)

• tiny animals (consumers) that feed on phytoplankton

• are a main nutrient source for many species of fish & whales

Fresh water biomes

• lakes

• ponds

• rivers

• estuaries

• wetlands

• ground water

Lakes

• have a littoral zone, photic zone, & profundal zone

• littoral zone: near shore where rooted plants can grow

• photic zone: where photosynthesis is possible

• undergo succession as they age

  • young __ contain few nutrients to support phytoplankton

  • as nutrients gradually accumulate, algae tint the water green

  • a continuous influx of sediments from the land eventually transforms the _ into a wetland

Littoral zone

• near shore where rooted plants can grow

• a broader term encompassing the intertidal area plus the immediately adjacent, perpetually submerged shallow water

Profundal zone

• the deep, cold, and dark bottom-water area of a lake or pond located below the limit of effective light penetration

Estuaries

• highly productive area where where freshwater from rivers meets salt water (river empties into an ocean)

• dynamic, partially enclosed coastal bodies of water where freshwater rivers or streams meet and mix with the salty ocean

• life is adapted to fluctuating salinity

  • salinity increases as approach ocean

• tides & river flow stir up soil

  • release nutrients

  • lots of plants & algae

    • extremely productive area

Wetlands

• shallow areas where water is trapped either permanently or seasonally

• distinct vegetation types

• could be saltwater, brackish, or freshwater

• found on every type of biome except ice cap

• ex. swamps, bogs, marshes, mangrove

Biosphere

• the zone where life on earth exists

• covers the entire surface of the earth

• extends 1.8 thousand miles below earths surface

• extends 5.2 thousand miles in altitude

• extends all the way to ocean bottom (~7 miles deep)

Community

• the collection of the populations of all species within a specified area

• interacting populations of several species

Biomass

• the total quantity or weight of organisms in a given area or volume

• the amount of living matter

Ecological dominants

• the few species that numerically dominate many communties

• usually plants

• high biomass

• species that exert a major controlling influence on an ecosystem's community structure, functioning, and biomass due to their high abundance, large size, or high productivity

Keystone species

• are not numerous or ecologically dominant, but if removed, drastically affect community diversity

• low biomass

• unique role in the community

• make up a small portion of the community

• those whose influence on a community is disproportionate to their biomass

• many are apex predators

• ex. sea otters, gray wolves, beavers, African elephants, and bees

Apex predators

• top predator

• top of food chain

• a species that preys on others but none prey on it

• ex. sea stars, wolves, lions, sharks, humans, tigers

Biodiversity

• species, geographic, genetic

• diversity of a community depends on…

  • species richness (the total # of different species present in a community)

  • species evenness (equal # of each species)

Species richness

• measure of biodiversity

• the total # of different species in a community

• ex. the 15 diff fish species in a lake

Species evenness

• measure of biodiversity

• equal # of each species

• measures the relative abundance (equality) of individuals among those species

• calculates the proportion of individuals of each species

• the proportion of the community that each species occupies

• measures how similar the abundances (population sizes) of those species are

Species diversity

• many different species (high biodiversity)

• few species (low biodiversity)

Geographic diversity

• broad distribution of species (high biodiversity)

• narrow distribution of species (low biodiversity)

Genetic diversity

• high genetic diversity within population (high biodiversity)

• low genetic diversity within population (low biodiversity)

Invasive species

• outside species that enters & rapidly takes over a community (selective advantage)

• often introduced by human intervention

• ex. rabbits in australia, zebra mussels in the great lakes, boa constrictor in florida

Habitat fragmentaition

• the breaking up of an organisms habitat into smaller, separate habitats

  • reduces, isolates, and degrades species’ ranges

• excessive __ __ can result in a loss of biodiversity + is a major cause of extinction + reduces genetic diversity

• can lead to allopatric speciation

The range of a species

• the entire geographical area in which it can be found

• has nothing to do with population size

• migratory species have a summer __ & winter __

Species intedractions

• competition (-/-)

• predatory (+/-)

• parasitism (+/-)

• mutualism (+/+)

• commensalism (+ / na)

• amensalism (- / na)

• neutralism (na / na)

na = neutral

Competition (species interaction)

• biological interaction where organisms or species vie for limited resources such as food, water, light, or territory in a shared environmen

• reduces the fitness of species that vie for limited resources in a shared habitat

effect on species X: negative

effect on species Y: negative

Predatory (species interaction)

• biological interaction where one organism (the predator) kills and consumes another living organism (the prey)

effect on species X: positive

effect on species Y: negative

Parasitism (species interaction)

• a close, long-term symbiotic relationship between two different species where one member increases its fitness at the expense of a living host

• one organism (the parasite) benefits by obtaining nutrients and shelter at the expense of another (the host)

• one species uses another to its advantage & harms it in the process

• ex. lamprey on fish

• ex. wasp eggs on hornworm

effect on species X: positive

effect on species Y: negative

Mutualism (species interaction)

• an ecological interaction between two or more species where all involved participants experience a net benefit

• type of symbiosis that improves the fitness of both partners

• ex. bees pollinating flowers

effect on species X: positive

effect on species Y: positive

Commensalism (species interaction)

• a type of symbiotic interaction between two species where one member increases its fitness without affecting the other member

• organism (the commensal) benefits—obtaining food, shelter, or transport—while the other (the host) is neither helped nor harmed.

• ex. One organism hitches a ride on another

effect on species X: positive

effect on species Y: neutral

Amensalism (species interaction)

• one species causes harm or inhibition to another organism without receiving any costs or benefits itself

• ex. accidental trampling of small plants by large animals

• ex. grass trampled by cows

effect on species X: neutral

effect on species Y: negative

Neutralism (species interaction)

• an ecological interaction in which two species coexist in the same habitat but do not affect each other's survival, growth, or reproduction

effect on species X: neutral

effect on species Y: neutral

Interspecific competition

• the rivalry between individuals of different species for shared, limited resources—such as food, water, light, or space—in an ecosystem.

• competitive exclusion

• resource partitioning

Competitive exclusion / Gause's Law

• 2 species competing for the exact same limiting resources cannot stably coexist

• 2 species cannot indefinitely occupy exactly the same niche

• the species with even a slight advantage will dominate, leading to the weaker competitor's local extinction or evolutionary shift to a different niche

Resource partitioning

• the division of limited resources by species to avoid competition in an ecological niche, enabling similar species to coexist

• by specializing in different food sources, habitats, or active times, species reduce direct competition for the same resources

• competition between multiple species with similar niches restricts each species to a subset of available resources

• helps maintain biodiversity

Evolutionary arms race

• a pattern of coevolution where two or more species reciprocally affect each other's evolution through continuous, escalating adaptations and counter-adaptations

• prey/host evolves a mechanism for evading/ fending off predator/ parasite

Biological Mimicry

• a species developed the ability to look like another either for defensive or offensive purposes

Mullerian mimicry

• a natural defense mechanism where two or more harmful, poisonous, or unpalatable species evolve to share similar warning colors or patterns

• occurs when species that have some protection against predators resemble one another

• all species in __ __ are actually dangerous or distasteful.

Batesian mimicry

• a form of, often, imperfect protective resemblance where a harmless species (the mimic) evolves to imitate the warning signals—such as bright, aposematic coloration—of a dangerous or noxious species (the model) to avoid predation

• relies on predators mistakenly avoiding the safe mimic due to prior negative experiences with the harmful model

Endosymbiont

• a mutualistic relationship when one organism lives entirely within the other

Coevolution

• 2 or more species evolving together as a result of their interaction

• interaction between species is so strong that genetic changes in one population select for genetic changes in the other

• reciprocal selective pressure in which a genetic change in one species selects for subsequent change in another species and vice versa

Ecological succession

• the gradual, predictable process by which the species composition of a biological community changes over time, often following a disturbance

• It describes how ecosystems shift from simple to complex structures

  • typically advancing from pioneer species to a stable, mature climax community (but true long term stability is rare)

Stage 1: Nudation/Bare Site: Succession begins with a disturbance—like a volcanic eruption (primary) or fire (secondary)—that creates a bare area with little to no life.

Stage 2: Pioneer/Invasion Stage: Hardened "pioneer species" (lichens, mosses, algae) arrive, colonize the area, and begin breaking down rock to form soil.

Stage 3: Intermediate/Competition Stage: As soil develops and nutrients increase, grasses, herbs, shrubs, and small trees establish. These plants compete for resources (light, water, nutrients), increasing biodiversity.

Stage 4: Climax/Stabilization Stage: The final stage, where a stable, diverse, and self-sustaining community (e.g., a mature forest) dominate

Primary succession

• the process of ecological succession that occurs in an area where no living organisms are present

• series of changes in a community’s species composition in an area previously devoid of life

• pioneer organisms: photosynthetic, r-selected

• over time: increase biomass, trend, toward k-selected

• general trend toward greater biodiversity

• competitive exclusion

Competitve exclusion

• the inevitable elimination from a habitat of one of two different species with identical needs for resources.

• two species can't have exactly the same niche in a habitat and stably coexist.

Pioneer organisms

• the first species to colonize an area devoid of life

• allows soil to develop, paving the way for additional organisms to thrive

• photosynthetic, r-selected

Facilitation

• action of earlier species help later species take over

• plants need nitrogen

• dryas shrubs “fix” nitrogen (bacteria are key)

• when dryas die/decompose, increase nitrogen levels

• nitrogen rich soil: alder bushes

  • have acidic leaves

  • accumulation of acidic leaves on ground = decrease soil pH

  • replace alder bushes with spruce

• moss grows at water line = forest floor watery

• blocks spruce from absorbing necessary nitrogen

• climax community: watery bog with moss as ecological dominant

Alder bushes

• nitrogen rich soil

  • have acidic leaves

  • accumulation of acidic leaves on ground = decrease soil pH

  • replace __ __ with spruce

Biological legacy

• what is left behind from previous conditions following major ecological disturbance

• living organisms, organic debris, and environmental patterns that survive a disturbance (like a fire, storm, or harvesting) to influence ecosystem recovery

Trophic levels

• the hierarchical position of organisms within a food chain or web based on their primary energy source

  • depends on the # of steps between it & the ultimate source of energy in the ecosystem

• energy flows from one __ __ to another

  • only a fraction of energy (~10%) is passed on

    • the rest is lost to the surroundings as heat

  • amount of available energy decreases as we move up __ __

  • a lot of organic matter inedible to organisms at next level

    • thats why large animals are rarer than small animals

• many organisms occupy more than one tropic level

  • ex. blue heron, humans

• 1st (base): primary producers

• 2nd: primary consumers (herbivores)

• 3rd: secondary consumers

• 4th: tertiary consumer

Herbivores

• consume plants & algae

Carnivores

• consume animals

Scavengers

• animals that feed on large dead and decaying organic matter

• ex. vultures

Omnivores

• consume plants & animals

Detritivores

• consume detritus (fungi & bacteria)

Detritus

• remains of smaller dead organisms or cast-off material from living organisms

• deces & dead organic matter

• ingest, digest, and excrete dead material

Decomposers

• special detritivore, feed on detritus (waste & dead organic matter), breaks it down into inorganic components, which are recycled through the ecosystem

• chemically break down material externally through enzyme secretion

  • + use oxygen to break down organic matter, which can deplete available oxygen in the surrounding environment

• converts the nitrogen in dead organisms back to ammonium

• finish the decomposition to return nutrients to the soil for producers

  • release carbon from once-living material

Primary producers

• photosynthetic organisms / autotrophs

• convert energy from sun into chemical energy stored as complex carbohydrates

• form the base of a food web by extracting energy & nutrients from nonliving sources

• autotrophs

• produce organic molecues by acquiring carbon from inorganic sources

• ex. on land: plants

• ex. in water: phytoplankton

Primary consumers

• herbivores

• organisms that get their energy by consuming primary producers