Ecology.pdf

(1)

• the study of the interactions of living things

with each other and their physical

environment

1

Man and Environment

(2)

• physical and chemical factors that affect

the ability of organisms to survive and

reproduce

− intensity of light

− range of temperatures

− amount of moisture

− type of substratum (soil or rock type)

− availability of inorganic substances

− supply of gases such as

oxygen, carbon dioxide, and nitrogen

− pH

2

Abiotic factors

Each of this factor varies in the

environment and may act as a limiting

factor, determining the types of organisms

that exist in that environment.

(3)

• All the living things that directly or indirectly affect

the environment

- the presence, parts, interaction of living

organisms, and wastes are all biotic factors.

3

Biotic factors

• Niche the organism's

functional role in the

community

• Habitat - a place where the

organism get their food,

water, shelter and space to

live in

(4)

• Population: all the members of a species inhabiting a given location • Community: all the interacting populations in a given area

• Ecosystem: the living community and the physical environment functioning together as an independent and relatively stable system

• Biosphere: a global ecosystem where organisms interact among them and with environment , includes part of atmosphere, hydrosphere and

lithosphere ₄

(5)

(6)

6

Population Interaction

• Niche- The sum of a species’ use of the

biotic and abiotic resources in its

environment

• Eugene Odum’s analogy: If an organism’s

habitat is its address, the niche is the habitat

plus the organism’s occupation.

• Eventhough niches tend to be specific to

given organisms, some closely related

species have niches that overlap to some

degree in a community.

(7)

• Symbiosis: living together with another

organism in close association

• Types of symbiosis

7

(8)

Mutualism: both organisms

benefit from the association

ex. nitrogen-fixing bacteria on

legume nodules, protozoa

within termites and ruminants

8

Parasitism: the

parasite benefits at

the expense of the

host, ex. athlete's

foot fungus on

humans,

tapeworm and

(9)

Commensalism:

one organism is

benefited and the

other is unharmed

ex. barnacles on

whales, orchids on

trees

9

• Competition occurs

when two different

species or organisms

living in the same

environment (habitat)

utilize the same limited

resources, such as

food, water, space,

light, oxygen, and

minerals

.

•

If two different

species compete

for the same

resources, one

species may be

eliminated.

•

This establishes

one species per

niche in a

(10)

A. Autotrophs can

synthesize their

own food from

inorganic

compounds and

a usable energy

source

(photosynthetic/

chemosynthetic)

10

Nutritional Relationship (Predation)

B. Heterotrophs can NOT synthesize

their own food and rely on other

organisms for their food

(11)

11

Nutritional Relationship (Predation)

Type of Heterotrophs

• Saprophytes: decomposers, live on

dead matter (heterotrophic plants,

fungi, and bacteria)

• Herbivores: plant-eating animals

• Carnivores: meat-eating animals

• Omnivores: consume both plants

(12)

Succession



Communities may change drastically after a

major disturbance such as flood and fire.



A variety of species may colonize the area

and may later be replaced by other species.



This

community

change

is

called

succession.



Rejuvenation of severely disturbed areas

provides us with insights on the importance

of living things and their products that

survive major ecological disturbance on the

future habitat.

(13)

Ecosystem Functions

• The ecosystem is the fundamental unit of Ecology.

• All communities need a source of energy, supply of

water, nutrients and gases.

• The process by which living things gain energy, for

instance from the sun, is through transformation

into heat.

• However, water and nutrients are being cycled,

from the Earth to the organism and then back into

the Earth.

• Considering this, ecological systems or functional

units that link biotic and abiotic factors to form a

whole can be perceived.

(14)

Ecosystem Functions

• Biomass- amount of organic material

• The rate at which producers build biomass is called primary productivity, which sets the spending limit for energy budget of the entire ecosystem because consumers acquire their organic fuels from producers.

• Energy flows as organic matter in trophic levels.

• The sun generally supplies ecosystems with energy but ecosystems depend on recycling as a means of acquiring essential chemical elements.

(15)

• Biomes are large land areas with similar environmental

conditions & characteristic plant communities

• Rainfall and temperature influences biomes distribution

which determine the available soil moisture needed for

plant growth and compensation for water losses through

evapotranspiration

15

(16)

Biomes

• Biomes are terrestrial climax

communities

with

wide

geographic distribution.

• Two primary abiotic factors

have major impacts on the

kind of climax community

that develops in any part of

the world: precipitation

(total amount and seasonal

distribution)

and

temperature.

• The temperature is warmest

near

the

equator

and

becomes cooler toward the

(17)

Biomes

• As the height above sea level

increases,

the

average

temperature decreases and the

higher the elevation, the cooler

the climate.

• This means that even at the

equator, in the tropics, it is

possible

to

have

cold

temperatures on the peaks of

tall mountains.

• As one proceeds from sea level

to the tops of mountains, it is

possible to pass through a

series of biomes that are similar

to what would be encountered

as one traveled from the

(18)

• Deserts-found

in

every

continent,

characterized by widely spaced vegetation and

large areas of bare ground

18

• A lack of water is the primary factor that determines that an area will be a desert.

• These are areas that generally have an average of less than 25 centimeters (10 inches) of precipitation per year and are mostly hot and dry during the day and cold at night.

• Organisms that thrive here are adapted to the arid and hot environment with plants showing very small leaves and stems that can store water (cactus) and animals with very thick skin or cuticle to prevent water loss (lizards).

(19)

19

Grasslands or prairie are concentrated in the center of continents, continuous cover

of grass and virtually no trees except along the rivers

• Grasslands, also known as prairies or steppes, are widely distributed over temperate parts of the world that generally receive between 25 and 75 centimeters (10 to 30 inches) of precipitation per year.

• These areas are windy with hot summers and cold-to mild winters.

• Fire is an important force in preventing the invasion of trees and releasing nutrients from dead plants to the soil.

• The primary consumers: large herds of migratory, grazing mammals like bison, wildebeests, wild horses, and various kinds of sheep, cattle, and goats.

• Most of the moist grasslands have been converted to agriculture for growing cultivated grasses like corn (maize) and wheat.

• The drier grasslands have been converted to the raising of domesticated grazers like cattle, sheep, and goats.

(20)

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• Savanna along the edges of tropical

deciduous forest, the trees are gradually wide

spaced with grasses growing between them

• Tropical parts of Africa, South America, and Australia have extensive grasslands spotted with occasional trees comprising the biome often called as the savanna.

• Rain is not distributed evenly throughout the year, typically, with a period of heavy rainfall is followed by a prolonged drought. • The predominant plants are grasses, but

many drought-resistant, flat-topped, thorny trees are common which are also resistant to fire damage.

• Many of these trees are particularly important because they are legumes that are involved in nitrogen fixation and also provide shade and nesting sites for animals. • Predominant mammals are the grazers.

(21)

Chaparral biomes are coastal regions that border on deserts, consisting of

small trees or large bushes with thick waxy or fuzzy evergreen leaves that conserve water which are able to withstand frequent summer fires started by lighting

21

• The Mediterranean shrublands are located near an ocean and have wet, cool winters and hot, dry summers with rainfall between 40 to 100 centimeters (15 to 40 inches) per year.

• This biome is typical of the Mediterranean coast and is also found in coastal southern California, the southern tip of Africa, a portion of the west coast of Chile, and southern Australia.

• The vegetation is dominated by woody shrubs that are dormant during summer as an adaptation to withstand the hot, dry period. • Fire is also a common feature of this biome, and the shrubs are adapted to withstand

occasional fires.

• Many kinds of insects, reptiles, birds, and mammals are found in these areas.

• In the chaparral of California, rattlesnakes, spiders, coyotes, lizards, and rodents are typical inhabitants.

(22)

• Tropical Dry Forest

• Tropical dry forests have rainfall as low as

50 centimeters (20 inches) or as high as

200 centimeters (80 inches), but since

the rainfall is highly seasonal with

extensive dry periods up to eight months,

many of the plants have special

adaptations for enduring drought.

• Many of the trees drop their leaves

during this dry period.

• Tropical dry forests are found in parts of

Central and South America, Australia,

Africa, and Asia (particularly India and

Myranmar).

• Many of the species of animals found

here are also found in more moist tropical

forests of the region. However, there are

fewer kinds in dry forests than in

rainforests.

(23)

• Tropical rain forests

dominated by huge

broadleaf evergreen

trees and have the

highest biodiversity

of any ecosystem

23

• Tropical rainforests are located near the equator in Central and South America, Africa, Southeast Asia, and some islands in the Caribbean Sea and Pacific Ocean.

• The temperature is normally warm and relatively constant.

• It rains nearly every day with most areas receiving in excess of 200 centimeters (80 inches) of rain per year. Some even receive 500 centimeters (200 inches) or more.

• Because of the warm temperatures and abundant rainfall, most plants grow very rapidly; however, soils are usually poor in nutrients because water tends to carry away any nutrients not immediately taken up by plants.

• Tropical rainforests have a greater diversity of species than any other biome. • The richest and threatened among the terrestrial ecosystems.

(24)

Temperate deciduous

forests-grasslands merge into temperate deciduous forest, has cold winters, usually with at least several frosts and often long periods of below freezing weather

26

• Forests in temperate areas of the

world that have a winter–summer

change of seasons typically have

trees that lose their leaves during

the winter and replace them the

following spring.

• Typical to the eastern half of the

United States, parts of south

central and southeastern Canada,

southern Africa, and many areas

of Europe and Asia.

• These areas generally receive 75

to 100 centimeters (30 to 60

inches) of relatively evenly

distributed precipitation per year.

• Have many fewer species, and

many forests may consist of two

or three dominant tree species.

(25)

Taiga -northern coniferous

forest, populated by evergreen coniferous trees with small waxy needles which reduce water loss by evaporation during the colder months and the leaves remains on the trees year round

27 Taiga, Northern ConiferousForest, or Boreal

Forest

• Throughout the southern half of Canada, parts of northern Europe, and much of Russia.

• The climate is one of short, cool summers and long winters with abundant snowfall. • The winters are extremely harsh and can

last as long as six months. Typically, the soil freezes during the winter.

• Precipitation ranges between 25 and 100 centimeters (10 to 40 inches) per year.

• Climate is typically humid because there is a great deal of snow melt in the spring and generally low temperatures reduce evaporation.

• The landscape is typically dotted with lakes, ponds, and bogs (swamps).

• Conifers such are the most common trees in these areas.

(26)

Tundra -the polar ice cap, a vast tree-less region

bordering the Arctic Ocean, a freezing desert

28

• North of the taiga is the tundra.

• This frozen soil layer is known as permafrost.

• Because of the permanently frozen soil and extremely cold, windy climate (up to 10 months of winter), no trees can live in the area.

• Although the amount of precipitation is similar to that in some deserts—less than 25 centimeters (10 inches) per year—the short summer is generally wet because the winter snows melt in the spring and summer temperatures are usually less than 10o_{C (50}o_{F), which}

reduces the evaporation rate.

• Many waterfowl like ducks and geese migrate to the tundra in the spring; there, they mate and raise their young during the summer before migrating south in the fall.

• When the top few centimeters (inches) of the soil warm up, many plants (grasses, dwarf birch, dwarf willow) and lichens, such as reindeer moss, grow.

• The plants are short, usually less than 20 centimeters (8 inches) tall.

• Many of the birds and large mammals migrate up to the alpine tundra during the summer and return to lower elevations as the weather turns cold.

(27)

(28)

• Represent the marine

ecosystem on Earth,

temperatures do not vary

as much as land biomes

(water absorbs and

releases heat)

• Organisms must maintain

water balance

• Freshwater

– Standing waters –

lakes, ponds

– Flowing waters –

streams, rivers

– Aquifers –

underground rivers

30

Aquatic Biomes

• Aquatic biomes, consisting of inland or freshwater and marine ecosystems, occupy the largest part of the biosphere.

• The most productive region in these biomes are the shallow-water area along its edge or the littoral zone.

• Then there’s the photic zone which starts at the surface and extends towards the point at which sunlight can no longer penetrate or where light is available for photosynthesis. • Phytoplankton-microscopic

photosynthesizing organisms that drift in the upper layers of water, form the base of aquatic food webs.

• A deeper layer called the aphotic zone has light levels that are too low to support photosynthesis.

• Furthermore, at the bottom of all aquatic biomes, the substrate is called the benthic

zone, consisting of organic and inorganic

sediments, and occupied by communities of organisms, including bacteria, collectively called benthos.

(29)

31

Lakes and Ponds

• Marine (salt) waters

-Coastal communities – salt

marsh, mangrove swamp,

seacoasts, mudflats,

estuary, seashores, coral

reefs (impt)

-Oceans – pelagic division

(open waters, neritic and

oceanic resources

-

Benthic division – ocean floor

(continental shelf, slope,

and abyssal plain)

• Brackish / Estuary – areas

where the freshwater from

rivers meet the saltwater of

the seas and oceans.

• Standing bodies of water range from small ponds to large lakes, where communities are distributed according to water depth and its distance from the shore.

• Lakes and ponds can be eutrophic, or nutrient-rich, or otherwise, oligotrophic. • Nitrogen and phosphorus are the mineral

nutrients that usually limit the amount of phytoplankton growth where large inputs of these nutrients are from sewage and runoff from fertilized agricultural fields. • Overabundance of these nutrients can lead

to overabundance of algae, also known as algal bloom.

• When this happens, decomposing bacteria flourish, depleting oxygen and causing fishes and other oxygen-dependent organisms to suffocate.

(30)

Rivers and Streams

• Rivers and streams are bodies of water flowing in one direction.

• It changes greatly between the source and the point where it empties into the lakes or oceans.

• Thus, supporting quite different communities of organisms.

• Factors such as current and channel affects the growth and abundance of phytoplankton and other aquatic organisms thriving in these ecosystems.

• Many rivers and streams have been affected by pollution from human activities as these are often used as depositories of waste, thinking that these would be diluted as water is carried downstream.

• Channelization and construction of dams are also examples of human interventions affecting these ecosystems.

(31)

Wetlands: Estuaries

• freshwater stream or river meets the ocean - estuary, bordered by extensive coastal wetlands called mudflats and saltmarshes.

• Nutrients and salinity, or concentration of salt, are the factors affecting these ecosystems.

• Much of these nutrients that enrich estuarine waters are carried from rivers, making estuaries one of the most biologically productive ecosystems on Earth, along with tropical rainforests and coral reefs.

• A wide diversity of aquatic organisms use estuaries as breeding grounds and organisms such as birds use them as feeding areas.

• However, these areas are also prime locations for commercial and residential developments and are unfortunately the receivers of pollutants dumped upstream.

(32)

Oceans

• Oceans cover about 75% of the Earth’s surface and have always had an enormous impact in the biosphere.

• Their evaporation provides most of the planet’s rainfall and photosynthesis by marine algae supplies a substantial portion of the biosphere’s oxygen.

• The ocean can be divided up in terms of the living things in it.

• The pelagic zone, supports

communities dominated by motile animals some of which feed on smaller zooplankton or phytoplankton.

• The tropical oceans form coral reefs. • So rich is this habitat that it is a home

to 25% of the ocean’s species but only covers 2% of the ocean floor.

• However, about 27% of the world’s coral reef is estimated to have now been lost as functioning ecosystems due to destructive practices and environmental disturbance

(33)

• Biodiversity encompasses all variation in living systems, including genetic, species, and ecosystem diversity.

• Scientists have discovered 1.8 million species and are still discovering new species - not only microorganisms but also plants, animals, and fungi.

• In general, biodiversity is highest near the equator, and decreases toward the poles.

• However, current rapid loss of species due to the destruction of many of our ecosystems may cause us not to know how many species really are there and how many we are losing.

• Why should humans care if biodiversity declines?

35

(34)

Human Impacts on Environment

• Humans, like all species, depend on certain natural resources for

survival. We rely on Earth’s biodiversity - the “millions of organisms

and hundreds of processes operating to maintain a livable

environment” - for food, water, clothing, medicines and for recycling

of nutrients and disposal of waste.

• In our dependence on these services, we are like all other species.

• Yet in many ways, we do not behave like other species.

• We have both the capacity to destroy or preserve our natural

resources.

• Man can harvest natural resources to exhaustion, and produce waste

beyond levels that the Earth can process or alter biodiversity, land,

water, air and fossil fuels beyond nature’s ability to repair. On the

other hand, we also have the ability towards conserving and

protecting our environment.

(35)

Habitat Loss

• Habitat

loss,

degradation,

and

fragmentation a primary threat to

biodiversity.

• Cause: Agriculture, forestry, mining, and

urbanization have disturbed over half of

Earth’s vegetated land.

• Effects:

• species disappear and biodiversity

declines.

• Half of Earth’s mature tropical forests

are gone; one-fifth of tropical rain

forests disappeared between 1960

and 1990.

• At current rates of deforestation, all

tropical forests will be gone by 2090.

(36)

Exotic Species

• Introduction of exotic animals to different areas/ habitats

• Many of these exotic (non-native) species, away from the predation or competition of their native habitats, have unexpected and negative effects in new ecosystems. Freed from natural controls, introduced species can disrupt food chains, carry disease, out-compete natives for limited resources, or prey on native species directly - and lead to extinctions.

(37)

Overexploitation

• Modern equivalent to over-kill

• Practices such as clear-cutting old growth forests, strip mining, and driftnet fishing go beyond harvesting of single species or resources to degrade entire ecosystems.

• Forest plantations, fish hatcheries and farms, and intensive agriculture

• Extinctions of very large animals could have had major effects on ecosystems, including secondary extinctions.

(38)

Global Climate Change

• Changing climates around Earth

• increasing reliance on fossil fuels is altering the Earth’s atmosphere and climate.

• Effects: acid rain, breaks in the ozone layer shielding us from ultraviolet radiation, and greenhouse gases which raise the Earth’s air and ocean temperatures and sea levels.

• changing air and water temperatures, rainfall patterns, and salinity threaten species adapted to pre-warming conditions, and biodiversity declines globally.

(39)

Overpopulation

• As human populations grow, natural ecosystems are continuously explored and converted displacing organisms from their homes.

• The demand to cater human needs increases extraction activities such as deforestation, mining, and fishing.

(40)

Pollution

• Air Pollution: Knows no boundaries and is a growing concern. Acid rain, ozone depletion, and global warming are all effects of air pollution

• Water Pollution: Industrial and agricultural chemicals, waste, acid rain, and global warming threaten waters which are essential for all ecosystems throughout the world. • Soil Contamination: Toxic industrial and municipal wastes, salts from irrigation, and pesticides from agriculture all degrade soils - the foundations of terrestrial ecosystems and their biodiversity.