Ecology.pdf

Man and Environment Ecology • the study of the interactions of living things with each other and their physical environment

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Abiotic factors • 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 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. 2

Biotic factors •

All the living things that directly or indirectly affect the environment - the presence, parts, interaction of living organisms, and wastes are all 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 3

Ecological Organization

• 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

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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. 6

Symbiotic Interactions/Relationships • Symbiosis: living together with another organism in close association • Types of symbiosis

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Mutualism: both organisms benefit from the association ex. nitrogen-fixing bacteria on legume nodules, protozoa within termites and ruminants Parasitism: the parasite benefits at the expense of the host, ex. athlete's foot fungus on humans, tapeworm and heartworm in dogs

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Commensalism: one organism is benefited and the other is unharmed ex. barnacles on whales, orchids on trees •

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 community •

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Nutritional Relationship (Predation) A. Autotrophs can synthesize their own food from inorganic compounds and a usable energy source (photosynthetic/ chemosynthetic) B. Heterotrophs can NOT synthesize

their own food and rely on other organisms for their food

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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 and meat

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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.

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.

Ecosystem Functions

Food energy available to the human population at different trophic levels. • •

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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.

Types of Ecosystem • 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

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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 poles.

Influence of Precipitation and Temperature on Vegetation

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 equator to the North Pole.

Relationship Between Height above Sea Level, Latitude, and Vegetation

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Deserts-found in every continent, characterized by widely spaced vegetation and large areas of bare ground • 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). 18

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, 19 sheep, and goats.

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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.20

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 • 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. 21

• 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.

• Tropical rain forests dominated by huge broadleaf evergreen trees and have the highest biodiversity of any ecosystem • 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. 23

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

• 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 26 or three dominant tree species.

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

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. 27

Tundra -the polar ice cap, a vast tree-less region bordering the Arctic Ocean, a freezing desert • • • •

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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 10oC (50oF), 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 28 elevations as the weather turns cold.

Aquatic Biomes • • •

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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.

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Lakes and Ponds • 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. 31

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.

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.

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

Biodiversity and Species Preservation • 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?

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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.

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.

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, outcompete natives for limited resources, or prey on native species directly - and lead to extinctions.

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.

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.

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.

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.

Solid waste

The use of packaging material which does not break down, burning of refuse, and the placing of materials in landfills prevents the return of some useful materials to the environment. 43

• Consume thoughtfully and wisely: Reduce consumption where possible,re-use, and recycle. • Sustainability as a guide for decision-making balances social, economic, and environmental values to structure human activities such that they can continue indefinitely.

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• Through a greater awareness and application of ecological principles, each individual can help to assure that there will be suitable environments for succeeding generations on our planet. Its up to you 45

Its up to you • Protect the wonderful world around you! • Remember each habitat is a unique place where plants and animals make their home. • We share this Planet with them…….it is not only ours! • We hold the future of this beautiful Planet in our hands. Our future and our children’s and their children’s future depends on the environmental choices we make today…..MAKE THE RIGHT ONES!!!!!! 46

“Every individual is a product of his/her GENES and ENVIRONMENT”

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