Welcome to BIOL 207 – General Ecology

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www.greenresistance.wordpress.com

Know that site.

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Homework due March 2

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Email me - as a MS Word Attachment - answers to the following question: (1) What is ecology? (give me your thoughts and not a definition that you find online.) (2) What are environmental and/or particular ecological questions that you want answered from this class? (3) Talk to elderly people in your communities (such as your grandparents) and tell me how the physical landscape of the environment in your village / neighborhood has changed during the past 50 years. Be sure to use correct grammar - both in the paper and in the email itself.

Extra Credit

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Chapter 1: Introduction

Robert E. RicklefsThe Economy of Nature, Fifth Edition

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But first…

What is new?

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the magnetism of cows?

- Cows can tell which direction is North

- reported in the Proceedings of the National Academy of Sciences that cows graze and rest facing either North or South, indicating they may be sensitive to the Earth's magnetic fields.

- Deer as well

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Chocolate and cows and climate change?

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Cow burping?

Cadbury is to encourage its cows to burp less to reduce the carbon footprint of its milk chocolate.

The company is working with its 65 dairy farmers in Wiltshire to reduce the emissions of their animals. Production of the famous glass-and-a-half of milk in every bar is responsible for 60% of the chocolate's carbon emissions, according to experts at the Carbon Trust who audited the carbon emissions from the company's products.

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Experts at the Institute of Grassland and Environmental Research have also looked at how the diet of farmed animals can be changed to make them produce less methane, a much more potent global warming gas than CO2.

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A moulting southern elephant seal scratches its head on Australia's remote World Heritage-listed territory of Heard Island in the Southern Ocean

News closer to home?

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Gazelles on a mountain side of the West Bank city of Hebron/Al-Khalil

Climate change threatens Lebanon's cedars

How?

"If there is no combination of rain, snow and frost for several consecutive days, the seeds of the cedar won't be disseminated. We also need cold treatment for the seeds to germinate. They also need summer mist, which compensates for water needs. Any change in these conditions for several consecutive years might eventually lead to the death of trees.” Fady Asmar, MoA

Drought was blamed for the infestation of a wood wasp called Cephalcia Tannourinensis that ravaged cedars in Tannourin village in northern Lebanon several years ago. "This wasp lives with the cedars in the same environment. But warm weather and rising temperatures have extended its life cycle from once a year to three times a year, leading to the problem of Tannourin…

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Background

Human perceptions of nature and mankind’s relation to nature: there is a balance of nature nature is pristine in the absence of humans

Ecological studies conclude otherwise: there is historical variation in nature the pervasive influence of human activities extends

to the most remote regions of the earth

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?

“Where we humans fit in a less than perfect world is a judgment each of you must make, guided by your own sense of values and moral beliefs. Regardless of your own stand, it will be more useful to you and to human kind in general if your judgment is informed by a scientific understanding of how natural systems work and the ways in which humans are a part of the natural world.”

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What is Ecology?

“By ecology, we mean the body of knowledge concerning the economy of nature -- the investigation of the total relations of the animal both to its organic and to its inorganic environment; including above all, its friendly and inimical relation with those animals and plants with which it comes directly or indirectly into contact -- in a word, ecology is the study of all the complex interrelationships referred to by Darwin as the conditions of the struggle for existence.” Ernst Haeckel, 1870.

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So, what is ecology? Ecology is the science by which we study how

organisms (animals, plants, and microbes) interact in and with the natural world.

Please note the important key words in the above definition!

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Ecology - A Science for Today

We have a great need for ecological understanding: what are the best policies for managing our

environmental support systems -- our watersheds, agricultural lands, wetlands?

we must apply ecological principles to: solve or prevent environmental problems inform our economic, political, and social thought and

practice

Example?

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Our Objectives...

We are on the road to ecological thinking: we’ll have many vantage points of varying

complexity we’ll understand ecological systems and the

interdependence of their components we’ll establish a core of principles regarding:

physical and chemical attributes regulation of structure and function evolutionary change

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Start here

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Ecological Systems Large and Small

Organism (“No smaller unit in biology ... has a separate life in the environment...”)

Population (many organisms of the same kind living together)

Guild (a group of populations that utilizes resources in essentially the same way)

Community (many populations of different kinds living in the same place)

Ecosystem (assemblages of organisms together with their physical environment)

Biosphere (the global ecosystem, all organisms and environments on earth)25

ecological systems

Ecological systems… human view

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Perspectives of Ecologists: Organism Approach

How do form, physiology, and behavior lead to survival?

Focus is on adaptations, modifications of structure and function, that suit the organism for life in its environment: adaptations result from evolutionary change by

natural selection, a natural link to population approach…

? - Why are trees the dominant plants in warm, moist environments – and shrubs the dominant plants in regions with cool, wet winters and hot, dry summers?

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Perspectives of Ecologists: Population Approach

What determines the numbers of individuals and their variations in time and space?

Focus is on processes of birth and death, immigration and emigration, influenced by: the physical environment evolutionary processes interactions with other populations, a natural link to

community approach…

? – Why have mosquitoes increased in number and in extent?

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Perspectives of Ecologists: Community Approach How are communities structured from their

component populations?

Focus is on the diversity and relative abundance of different kinds of organisms living together, affected by: population interactions, promoting and limiting

coexistence feeding relationships, responsible for fluxes of energy

and materials, a natural link to ecosystem approach...

? – what is the relationship between birds, crops, and insects?

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Perspectives of Ecologists: Ecosystem Approach

How can we account for the activities of populations in the common “currencies” of energy and materials?

Focus is on movements of energy and materials and influences of: organisms large and small climate and other physical factors, including those

acting on a global scale, a natural link to biosphere approach...

? – movement of Nitrogen… ?

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Perspectives of Ecologists: Biosphere Approach How can we understand the global

movements of air and water, and the energy and chemical elements they contain?

Focus is on the global circulation of matter and energy, affecting: distributions of organisms changes in populations composition of communities productivity of ecosystems

? – climate change ?!

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Kinds of Organisms and Their Ecological Roles

Characteristics of ecosystems depend on varied forms of life: plants and animals are conspicuous and

important, but no more so than more primitive forms,

like the bacteria, which dominated much of earth’s early

history, making it possible for their more complex

descendents to survive!

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Plants use energy in sunlight to produce organic matter.

Plants capture the energy of sunlight and transform it into chemical form.

Plants must use external surfaces for absorbing light and exchanging gases, water, and nutrients.

Plants stay closely attached to their sources of water, from soil, atmosphere, or bodies of water.

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Epiphytic air plants (cloud mists)

Animals feed on other organisms or their remains.

Animals depend on organic foods ultimately produced by plants.

Animals can use internal surfaces for exchange of gases, nutrients, and water.

Animals can assume streamlined shapes, with other systems permitting motility.

Animals can be less directly tied to sources of water than plants.

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Fungi are highly effective decomposers.

Fungi assume unique roles in ecosystems because of their distinctive form.

Fungi penetrate dead materials effectively, making nutrients available to others.

Fungi digest externally, and capture inorganic nutrients and water from soils.

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Protists are single-celled ancestors of more complex life forms.

Protists are highly diverse single-celled forms, including algae, slime molds, and protozoa.

Protists lack specialized tissues and organs, yet fill almost every ecological role: photosynthetic organisms grazers and predators decomposers

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Bacteria have a wide variety of biochemical mechanisms for energy transformations.

Bacteria consist of simple, single cells lacking nuclei and chromosomes.

Bacteria are biochemical specialists, accomplishing unique transformations: nitrogen fixation chemoautotrophic production metabolism under anaerobic conditions

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Organisms cooperate in nature.

Many types of organisms live together in close association, forming symbioses: each partner provides something the other lacks examples of symbiotic relationships include:

lichens (fungus and alga) bacteria fermenting plant material in a cow’s gut beneficial fungi associated with the roots of plants photosynthetic algae in corals and clams nitrogen-fixing bacteria in root nodules of legumes

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Habitat and Niche The habitat is a place or physical setting in which

an organism lives. Examples include: forests deserts coral reefs

The habitat is characterized by: conspicuous physical features dominant plant (or animal) life

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Classifying habitats is useful but difficult!

The habitat concept is useful; it emphasizes conditions experienced by organisms.

Classification systems are varied and typically hierarchical: aquatic habitats (vs. terrestrial)

marine habitats (vs. freshwater) oceanic habitats (vs. estuarine)

benthic habitats (vs. pelagic)

Finer subdivisions overlap rather broadly!

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Niche

The niche of an organism encompasses: ranges of conditions tolerated role in ecological systems

No two species have the same niche: each has distinctive form and function

No organism can live under all conditions: each has unique habitat requirements each has a unique niche

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Systems and Processes: Dimensions in Time and Space

Nothing in nature is static: anything we can measure (conditions, number of organisms) exhibits variation.

Variation has temporal and spatial components.

Variation in each measurement has a characteristic scale; for the same degree of change: air temperature varies over hours ocean temperature varies over weeks or months

(weather vs climate?)

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Temporal Variation

Consider two kinds of temporal variation: predictable, cyclic variations (daily, seasonal) unpredictable, irregular variations

A temporal “rule of thumb”: the more extreme the condition, the less frequent

(compare cold fronts and hurricanes) … but… but frequency and severity are relative terms that depend

on the organism!

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Spatial Variation

Spatial variation occurs at very small (forest sunflecks) and very large (latitudinal variation in solar flux) scales.

Scale of variation importance is a function of the organism: the two sides of a leaf are different to an aphid a moose eats the whole leaf, aphid and all

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Time and Space

A few generalizations: moving organisms experience spatial variation as temporal

variation the faster an individual moves:

the smaller the scale of spatial variation the more quickly it encounters new environments the shorter the temporal scale of variation

spatial and temporal scales are correlated frequency is inversely related to extent/severity

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Physical and Biological Principles 1

Ecological systems are physical entities: life builds on physical properties and chemical

reactions of matter all processes obey the physical laws of

thermodynamics (?) but life still pursues many varied options

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Physical and Biological Principles 2

Ecological systems exist in dynamic steady states: despite substantial fluxes of energy and matter,

ecological systems remain more or less unchanged gains and losses are more or less balanced steady states apply to fluxes of materials and

energy at all levels of ecological organization

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Physical and Biological Principles 3

The maintenance of living systems requires the expenditure of energy: life forms exist out of equilibrium with their physical

environment losses must be replaced by energy or materials

procured by the organism the price of maintaining a dynamic steady state is

energy

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Physical and Biological Principles 4

Ecological systems undergo evolutionary change through time: physical and chemical properties, and physical laws, are

immutable, but life exhibits remarkable diversity structures and functions of organisms (adaptations) are

evolutionary products of natural selection, recognized by Charles Darwin

complexity builds upon complexity

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How Ecologists Study the Natural World

Ecologists, like other scientists, employ a scientific method: observation and description of natural phenomena development of hypotheses or explanations testing the predictions of these hypotheses

We test hypotheses because many explanations are plausible. Which is best?

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Ecology Employs the Scientific Method

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observationobservation

predictionprediction

experimentexperimenthypothesishypothesis oror modelmodel

inductioninductioninductioninduction

deductiondeductiondeductiondeduction

Start here

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What is an hypothesis?An hypothesis is an idea

about how the world works: e.g., “Frogs sing on warm

nights after periods of rain.”

We often wish to understand two components of such a phenomenon: how? (encompasses

physiological processes) [how does a frog respond to temperature and rainfall?]

why? (encompasses costs and benefits of the behavior to the individual) (how to answer..)

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Experiments test predictions.

Hypotheses generate predictions: if observations confirm the prediction, the

hypothesis is strengthened (not proven) if observations fail to confirm the prediction, the

hypothesis is weakened (or rejected)

Best tests of hypotheses are experiments: independently manipulate one/few variables (or

trick frogs into singing on a ‘wrong’ night) establish appropriate controls

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Some Potential Pitfalls

A correlation between variables does not establish causation.

Many hypotheses cannot be tested by experimental methods because: the scale is too large:

patterns may have evolved over long periods the spatial extent is too large for manipulation

causal factors cannot be independently tested

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Some Approaches to Difficult Problems

Mathematical models are powerful tools: researcher portrays system as set of equations model is an hypothesis and yields predictions that can be

tested; examples include: models of disease spread models of global carbon

Microcosms are sometimes useful: microcosms replicate essential features of the system in a

laboratory or field setting

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Microcosms…communities of freshwater invertebrates

Hypothesis: bird predation on insect herbivores reduces the amount of leaf area consumed. Field Study: construct bird-proof cages to allow insects freedom of movement.

Yes: insects increased 70% -> leaf area % lost increased 22% to 35%

So?

Leads to important question:

Will the decreases in bird populations caused by fragmentation of forests in the eastern US and elsewhere result in increased insect damage to forests?

Other questions?

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Start here

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Humans are a prominent part of the biosphere.

Why study ecology?

the wonders of the natural world stimulate our curiosity and our desire to understand our surroundings

a growing human population increasingly stresses the natural world, causing two related problems: impact of humans on natural systems deterioration of our own environment

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A Focus on Human Impacts Human impacts are everywhere

We are inundated with environmental problems (disappearing tropical forests, ozone hole, depleted fish stocks, etc.). Nile perch California sea otter (otter sea

urchins kelp (seaweed); ( sea lions and seals whales -> otter…)

Tuna…

Increasingly, the only effective means of preserving natural resources is through conservation of entire ecological systems and management of broad-scale processes.

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Success Stories Many positive efforts are underway:

cleanup of rivers, lakes, and air reduction in acid rain reduction in release of chlorofluorocarbons widespread focus on CO2 and global warming

protection of endangered species international cooperation (IUCN, WWW) international agreements (CITES, Rio)

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Summary Ecology is the scientific study of the natural environment and

the relationships of organisms to one another and to their surroundings.

Ecologists study a variety of organisms and processes, spanning a wide range of spatial and temporal scales.

Individual organisms live in habitats and have unique niches reflecting conditions tolerated and functional role.

All ecological systems obey natural laws and are subject to evolutionary change.

Ecologists employ the scientific method.

Humans are part of the global ecosystem and have created numerous environmental problems. Solving these problems will require application of ecological principles.

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For you to do - soon

Today: Online quiz for Chapter 1 Homework – due by midnight today Familiarize yourself with the website

www.greenresistance.wordpress.com

And

Read chapter 2 by Wednesday

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