4.3 Human impacts on ecosystems

Loading...

From the course by National Research Tomsk State University

Ecology: from cells to Gaia

58 ratings

National Research Tomsk State University

Ecology: from cells to Gaia

58 ratings

This course presents the principles of evolution and ecology for citizens and students interested in studying biology and environmental sciences. It discusses major ideas and results. Recent advances have energised these fields with evidence that has implications beyond their boundaries: ideas, mechanisms, and processes that should form part of the toolkit of all biologists and educated citizens. Major topics covered by the course include fundamental principles of ecology, how organisms interact with each other and their environment, evolutionary processes, population dynamics, communities, energy flow and ecosystems, human influences on ecosystems, and the integration and scaling of ecological processes through systems ecology. This course will also review major ecological concepts, identify the techniques used by ecologists, provide an overview of local and global environmental issues, and examine individual, group and governmental activities important for protecting natural ecosystems. The course has been designed to provide information, to direct the student toward pertinent literature, to identify problems and issues, to utilise research methodology for the study of ecology and evolution, and to consider appropriate solutions and analytical techniques. Needed Learner Background: general biology and a good understanding of English. This course has the following expectations and results: 1) covers the theoretical and practical issues involved in ecology and evolution, 2) conducting surveys and inventories in ecology, 3) analyzing the information gathered, 4) and applying their analysis to ecological and conservation problems.

From the lesson

Module 4. Population Ecology and Evolution

In this final module, we will explore the possibility of a new ecology by exploring the concept of sustainability, evaluating the human impacts on ecosystems and providing some solutions for nature conservation. Finally, we will see how to organise a citizen science event, called Bio-blitz, which can improve the scientific knowledge of our planet and, at the same time, rise the ecological awareness of citizens.

4.3 Human impacts on ecosystems6:43

Meet the Instructors

Roberto Cazzolla Gatti
Ph.D., Associate Professor in Ecology and Biodiversity
Biological Diversity and Ecology Laboratory, Bio-Clim-Land Centre of Excellence, Biological Institute

[MUSIC]

Hi learners.

Welcome to the 80th lecture of my course, Ecology from Cells to Gaia.

Today we will talk about human impacts on ecosystems.

People physically degrade or

chemically polluting natural ecosystem when generating power or

developing land for agricultural, urban, or industrial purposes.

Human beings are not unique among species in degrading their environment and when

our population density was low, and prior to our harnessing of non-food energy.

Humans probably had no greater impact than many other species.

But now the scale of human effects is proportional to our huge numbers and

advanced technologies.

Habitat degradation has costs in terms of human health and loss of ecosystem

services, including provisioning services such as wild food or drinking water,

cultural services including education or recreational opportunities.

Regulating services,

such as the ecosystem's ability to break down pollutants or regulate climate, and

supporting services including primary production and soil formation.

The intensive production of livestock in factory farming is seriously polluting,

and the agricultural law we made need to be thinly dispersed over extensive

farmland to deal with it to a level that natural decomposers can deal with it.

Intensive agriculture is associated with an increase in the nitrate and

phosphate deliverance into rivers, lakes, and oceans.

The consequent eutrophication may be counteracted by matching fertilizer supply

to crop demand, restoring natural wetlands, or constructing artificial ones.

To take up some of the excess nutrient before they enter rivers and

the lakes by manipulating,

biomanipulating the level [INAUDIBLE] phytoplankton to increase water clarity.

Many manufactured pesticides have become important environmental pollutants.

Problems arise when pesticides are toxic to many more species than just the target,

and particularly when they drift beyond the target areas and

persist in the environment.

The organochlorines insecticides have been particularly problematic

because they are progressively biomodified in animals farther up the food chain.

Top predators in aquatic and terrestrial food chains which were never intended

as targets can then accumulate very high doses.

Cultivation can also physically degrade the landscape through the loss

of habitat diversity, while heavy irrigation depletes water in rivers and

changes the pattern of flow with adverse consequences for river inhabitants.

The polluting effects of burning coal and

oil include acid rain which can affect lakes in forests in neighboring countries.

And a dramatic increase in the atmospheric carbon dioxide which is responsible for

climate change on a global level.

Recent emphasis has been placed on developing alternative energy sources that

do not release carbon dioxide.

The cleanest and

safest technologies are expected to derive from hydropower schemes.

Already at the chrononological advanced state in many part of the globe,

together with wind farms, rapidly developing but

with potential adverse consequences for migrating birds, and solar and wave power.

Nuclear power, whose popularity has declined because of

concern over security and radioactive waste disposal,

is receiving renewed consideration because it doesn't release greenhouse gases.

But there is the fundamental problem of where and

how to store the radioactive wastes.

Our feces and urine create large disposal problems in towns and

cities because density is so high.

At the simplest primary sewage treatment simply removes most of the solid

organic matter.

Secondary treatment mimics natural decomposition processes,

eliminating organic matter, but leaving high concentration of nitrate and

phosphate in the wastewater.

Tertiary treatment chemically remove these nutrients.

Industrial chemicals also find their way into waterways and

the atmosphere, where they cause diverse problems.

For example, chlorofluorocarbon compounds, CFCs, developed as aerosol and refrigerant

and used on a very large international scale, were found to pose a threat.

The chlorine content could interact with and destroy atmospheric ozone,

which normally protects the world's biota from harmful UV radiation.

The chlorine content could interact with and destroy atmospheric ozone,

which normally protects the world's biota from harmful UV radiation.

International agreement to phase out CFCs is expected to solve the problem by 2050.

Including recovery of the substantial ozone hole that form annually over

Antarctica.

Mining activities whether for fossil fuels or metals, also cause physical and

chemical degradation to surrounding ecosystems.

For example more than one million tons of oil enters the world's waterways every

year from wells drilling into the sea bed, or

from oil tankers with adverse consequences for marine life.

Mining for metals such as copper may also pollute at every stage of extraction,

purification, and disposal.

Land that has been damaged by mining is usually unstable, liable to erosion, and

devoid of vegetation.

The simplest solution to land reclamation is the re-establishment of vegetation

cover, because this will stabilize the surface, be visually attractive, and

self sustaining.

Candidate plans for

reclamation are those that are tolerant to toxic heavy metal present.

The concept of ecosystem services brings into focus three very different ways of

looking at our effect on natural world.

The triple bottom line on environmental, economic, and sociopolitical perspectives.

Planning for sustainable use of natural resources

usually needs to be carried out at regional or global scales.

The impact of agriculture depends on the proportion of landscape that is used for

production.

And planning needs to be done at the regional scale and involve the knowledge

of experts in environmental, economic, and sociological disciplines.

Dealing with the diversity of view among neighbors is difficult enough.

But our biggest environmental problem,

such as climate change due to large measure to the burning of fossil fuels

requires a multinational global level of planning.

So at the end of this lesson, I have some question for you as usual.

What's the pollution problems are you contributing to?

How are we causing the loss of tropical forest?

What are the main drivers for biodiversity decline?

So try to answer these questions, and see you at the next lecture.

[MUSIC]

Explore our Catalog

Join for free and get personalized recommendations, updates and offers.

Coursera provides universal access to the world’s best education, partnering with top universities and organizations to offer courses online.

© 2019 Coursera Inc. All rights reserved.

Download on the App Store

Get it on Google Play