Intro to Envi

8/20/2019 Intro to Envi

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ONE

rtw@ff*ftSy

EcOLOGICAL

TERtvrs

AND

CONCEPTS

FIRSr

PRINCIPTE'

There

are

a

number

of

terms

and

concepts

that

are

fundamental

to

the

study

of

environmental

science.

Some

basic

definitions

and

explanations

are

listed

below.

Defnitions

The living

components

of

the

environment,

such

as

plants,

animals

and

fungi,

are called

the

biotic

components.

The

non-living

coftLponents

of

the

environment,

such

as

sunlight, rock

types, slope, geographic

setting

and

climate,

that

affect

ecological

functions,

are

called

the

abiotic

comPonents.

An

ecosystem

is

a

natural

unit

of

livingor

biotic

components,

together

with

non-living

or

abiotic

surroundings,

through

which

energy

flows

in a

nutrient

cycle.The

biotic

and

abiotic

components

influence

each

other

in

many

ways,

interacting

to

form a

relatively

stable

system.

An

example

of

a

small

ecosystem

is

a

Pond.

Ecosystems

are

relatively

self-contained.

Any

ecosystem

tends

to

perpetuate

itselfby

cycling

and

iecycling minerals

within

itself.

Examples

of

individu.al

ecosystems

include

salt

marshes,

corcI

reefs,

ponds, lakes

and

mangrot

es.

An

ecosystem

may

also

be

defined

as a

dynamic

complex

of

plants and

animals

and

microorganism

c ommunities

and

their

non-liv

ing

env

ir onment,

interacting

as a

functional

unit.

A

habitat is

the

locality

in which

an

organism

occurs;

it

is where

the

organism

is

normally

found.

If the

area

is extremely

small,

it

is called

a

microhabitat.

The

wasps

that

make

a

home

in

the

bark

of

a

tree,

or water

beetles living

under

rochs

on a

riverbed,

are in

their

own

microhabitats.

The

habitat

may also

be

defined

as

the

place or

type

of

site

where

an

organism

or

population naturally

occurs.

A

species

is a

group

of

organisms

that

have

numerous

physical

features

in

common

and

that

are

normally

capable

of

inter-breeding

and

producing

viable

offspring.

The species

is

the

basic

unit of

biological

classification.

7

A

population

consists

of

all

living

things

of

the

same

species

in a

habitat

at

any

one

time.

The

members

of

a

population

are capable

of

breeding

among

themselves,

assuming

that

the

species

concerned reproduces

sexuallY.

A

community

consists

of

all

living

things

in

a

habitat.

It

is

the

total

of

all

populations

in

the

habitat.

The community

of

a well'stoched

pond

would

include

the

population of

rooting,

floating

and

submerged

plants, the

populations

of

bottom-Iiving

animals,

of

fsh

and of

non-vertebrates

of

the

open

water.

The

niche

of

an organism

is

its

role

or

function

within

the

ecosystem.

It

is the

contribution

of

each

organism

to

the

success

ofthe

ecosystem

that will

lead

to

a

balanced

and stable

environment.

While

thehabitat

is defined

as

the

physical

location

of

the organism,

the

niche

relates

to

the

functional

role

of

the

organism,

including

the

eating

habits,

predator-prey

relations

and

physical

location.

The

niche

therefore

incorporates

the

habitat

of

the

organism.

The

Earth's

mantle

is

the

layer that

lies

directly

below

the

Earth's

crust

and

above

the

Earth's

outer

core.

It

extends

from

30 to

2900

kilometres

below

the

surface.

The

atmosphere

of

a

planet

comprises

gases that

are

held around

the

planet

by

its

gravitational

force.

The

lithosphere

is the

upper

layer

of

the

Earth.

It

includes

the

oceanic

and

continental

crusts

and

parts

of

the

cooler,

solid,

upper

mantle.

The

hydrosphere

is

that

part of

the

Earth

that

is

composed

of

water

and

includes

clouds,

oceans,

seas,

ice

caps,

glaciers,

lakes,

rivers,

underground

water

supplies

and

atmospheric

water

vapour.

The

part of

the

Earth that

includes

all the

land

masses

and

water

masses

is

called

the

geosphere.

It

comprises

the

lithosphere

plus

the

hydrosphere.

The

region

outside

the

geosphere

is

the

atmosphere.

The

part

of the

Earth

that

is

able

to

support

life

is

known

as

the

biosphere

or

zone

of

life.

The

biosphere

extends

from

the

bottom

ofthe

ocean

to

the

upper

atmosphere

but

amounts

to

only

a

relatively

narrow

layer

around

the

Earth;

it

includes

the

atmosphere,

hydrosphere

and

parts



4

I

li

of thelithosphere.The

study

of

ecology

sets

out

to explain,

among

other things,

the

distribution

patterns

within

the

biosphere.

The

border

between

two

major ecosystems

is

called

the

ecotone.

Examples include

features

such as

coastlines

that

separate

the

ocean

from

the

land.

This

transition zone contains

plants

and

animals

from the

adjacent ecological

regions.

It

also

supports

many

species

not

found

in

the bordering

ecosystems.

An ecotone

has

features

and

conditions

that

are

different from those

of

the two

ecosystems

it

separates;

this

encourages

the survival

of species

from both

ecological

systems.

*

It

supports

many

species

not

found in either

of

the bordering

ecosystems.

*

It

may

contain

a

mixture

of species

and many

unique

species.

*

It contains

plants

and

animals

from

adjacent

regions.

t

Figure

|

,I

An

ecotone: on

the

left is

a

freshwater rtver

and on

the

right

ls

the ocean;the ecotone

ts

the

sand

bar

in

the

middle.

A

biome

is a regional ecosystem

or major

life

zone,

characterised

by

distinct

types of vegetation,

animals and

microbes

that

have

developed

under the

specific

soil

and

climatic

conditions

typical

ofthe

region. Tropical

rainforest,

deciduous

woodlands, coniferous

forest,

mangroves, sea

grassbeds

and

grasslands are examples of

biomes.

Any

species

that

is

rare,

vulnerable

and

in

danger

of dying out, or

becoming

extinct, is

a threatened

or

endangered species.

Examples include the blue

and

gold

macaw,

found

in

Trinidad.

+

Figure

1.2

The blue and

goid

macaw

j.:

.t..

.,:-,i

.r..

:.:..

a.

t..-;.',.1,t.

;'U;-1''

:.'i,r,

*

Threatened

species

-

anv

species

that

is rare,

vulnerable

and endangered

+

Ecosystem

*

a dynamic

complex

of

plant,

animal and microorganism

communities

and

their

non-living environment,

interacting as a

functional unit

*

Habitat

-

the

place

or

type

of

site

where

an

organism

or

population

naturalil'

occurs

*

Biome

-

a regional

ecosystem

that

has

its own

distinctive

climate

and

soil conditions

and

a

definitive

biological community

that

is

adapted

to

these

conditions

*

Indigenous

-

native to

a

particular

area

*

Animal

-

any member

of the animal

kingdom,

whether

alive

or

dead,

in

any

stage

of

biological

deveiopment;

also refers

to

any

part

or

product

thereof

*

Managed

resource

protected area

-

an

area

containing natural

systems

that

are

largely

unspoilt, but that

require ongoing

use and

management to

protect

and

maintain their

state

of

biological diversity,

rvhile,

at the same

time,

providing

a

sustainable

flow of

natural

products

and

services

to

meet

the

needs

of

the

community

*

Natural

resources

-

the

living

plants,

animals,

organisms and

other biological

factors

within

the

environment

and the

geoiogic

formations,

mineral

deposits,

renewable and

non-renewable

assets

and

the

habitat of the living

plants,

animals,

organisms and

other biological

factors

*

Plant

-

any

member

of the

piant kingdom,

whether alive or

dead,

in

any

stage

of biological

development; also

refers

to

any

part or

product

of

these

*

Rare

-

infrequently occurring; the

rarity of

a

species

may

or

may

not result from

human

activity

*

Sustainable

resource

use

-

natural

resources

and ecosystems

should

be

used

in

such

a

way

that their ability to

recover is

not

put

at

risk

*

Vulnerable

-

the

state

of

a

species

with

a

life history

that

makes

it

prone

to

population

depletion

and consequent endangerment

by

human

activity

CHAPTER

1 THE

STUDY

oF ECOLOCY



.

BToGEOCH

EtvtICAI

CYCLES

Carbon,

in

its various

forms,

moves

between

the

biosphere,

atmosphere,

oceans

and

geosphere'

This

movement

is

described

as

the

carbon

cycle.

Within

the

carbon

cycle

there

are

carbon

sinks,

which

are areas

that

absorb and

hold

large

amounts

of

carbon

dioxide.

Examples

include

oceans,

soil,

rocks,

peat dePosits,

fossil

fuels

and

forests.

Again,

within

the

cycle,

a

carbon

sink

may

become

a carbon

source.

These

are

processes

or

sources

that

provide

or

produce

carbon,

often

in

the

form

of carbon

dioxide,

for

example,

the

combustion

of

fossil

fuei

and

respiration.

il

Cellular respiration

Detritivores

(soil

microbes

and

others)

Figure

L3

The

carbon

cYcle

A

living forest

is a

carbon

sink,

absorbing

more

carbon

than

it releases.

When

a

forest

burns,

however,

it becomes

a carbon

source

as

it

releases

lots of

carbon

into

the

atmosphere.

'.{

'i.-.'

l'r.':.r.ir':' i,-tr'g-

3r,-

Water

can take

three

forms,

as

it

circulates

from

the

land to

the

sky

and

back

again.

The

path

it

takes

is

called

the

water

cycle,

also

known

as

the

hydrological

cycle.

Heat

from

the

Sun

provides energy

for water to

evaporate

from

oceans

and

lakes

on

the

Earth's

surface.

Animals

and

plants

breathe

out

water,

in the

form

of

water

vapour,

in

the

process

of

respiration.

Plants

also

lose

water

to the

air,

in

a

process

cal1ed

transpiration.

Tire

water

vapour

rises,

then

eventually

condenses

in tiny

droplets

to

form

clouds.

When

the

clouds

meet

cooi

air

over

land,

this

causes

precipit::ion

in

the

form

of

rain,

sleet,

or

snow,

so

lvater

ieturns

to

the

4

Figure

1.5

Carbon

source

Iand

or

sea).

Some

of

this

water

soaks

into

the

ground.

Water

that

is

trapped

between

rock

or

clay

layers

is called

groundwater.

Most

water'

however,

flows

downhill

as run-off

(both

above

ground

and

underground).

Eventually,

the

water

joins

streams

and

lakes,

returning

to

the

ocean

as

slightly

salty water.

Burning

#-@

#i*

Photosynthesis

Figure

1.4

Cadron

sink

i

il

.ra

1-l:;*:.,:r: rr:r:::{

Tl..



Vapour transport

Surface

runoff

River

\,

lil

recipitation

Groundwater

flow

CHAPTER 1

THE STUDYOF

ECOLOcY

5

+

Figure

1.8 RinconWater

fall



Phosphorus

occurs

in

water,

in soil

and

in

sediments.

It

does

not

have

a

gaseous

state

and

it

is

not

found

in the

atmosphere,

except

in

minute

dust

particles.

The

phosphorous

cycle

has

no

atmoipheric

phase.

Phosphorus

is

transported

in

"qu"out

form.

Inorganic

phosphorous

is taken

ii

by

producer

organisms

(plants),

incorporated

into organic

molecules

and

passed

on

to

consumers

(that

feed

on

producers).

It

returns

to

the

environment

through

decomposition'

Replenishment

is

very

slow.

Phosphorous

that

is deposited

on

the

sea

bed

is

usually

lost

to

the

cycle.

Nitrogen,

in both

the

atmosphere

and

the

soil,

go"t

thtough

many

complex

changes,

chemical

ind

biological.

It is combined

into

living

and

non-living

material

and

eventually

returns

to the

soil

or

air

in a

continuous

cycle.

This

is called

the

nitrogen

cycle.

Rain

{ffi

"d

:h.. ,.+.-qde.@'

+:g

.,11

' to

?.

of

phosphate

from rocks

i

'

t

offo:o{'rc;l"%:%:

'

O

^.\e*...7

V\J

Y

Q.-..,wq-

(J,qC/

5|:tr

6

4

€NQ

ubato

-

.C

&,lf

Animals

Leachi16

-,4

Phosphate

in solution

a

Chemical

precipitation

I

Detritus

pettling

to boftom

*

,

*

:

{

t

Decomposers

t

Figure

1.9

The

PhosPhorus

cYcle

6

a\

Sedimentation

=

new

rocks



a

i

_q

,;

t

(

a

e

:

*

*-

it

F'l

Animal

waste

and

plant

matter

Nitrates

increased

by

decay

and

nitrifying bacteria

Nitrites

increased

by

nitrogen-fixing

bacteria

(legume

root

nodules)

Nitrates

decreased

by

denitrifying

bacteria

Nitrates

decreased

by

plants

to

make

proteins

:

?rre

I

.lO

The nitrogen cycle

\itrogen

fixation

is the

process

of converting:

gaseous

nitrogen

to ammonia

by bacteria

in soil

and

root

nodules

-

ammonia

dissolves

in soil

moisture

gaseous

nitrogen

can also

be

converted

into

ammonia by

lightning.

Nitrification

Ammonium ions

are converted

into

nitrite

ions

under anaerobic

conditions.

Nitrite

ions are

converted

to

nitrate

ions by

nitrifying

bacteria.

Denitrification

Under

anaerobic

conditions,

denitrifying

bacteria

convert

nitrate

ions in the

soil

back

to

nitrogen

gas

which

escapes

into the

atmosphere.

Figure I I I

Lightning converts

(fixes)

atmospheric

nitrogen

to

ammonia

CHAPTER

1

THE STUDY

OF ECOLOGY

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