Biology 216 EcologyMark PyronProfessorCL 229285-8852mpyron@bsu.edu

SyllabusOnline:Blackboard

ebook required:

Molles 7th edition

Attendance is required -

Assignments:

Reading assignments

Read online chapter

Answer questions

Written assignments

Cheating

• Zero grade for all involved

• Grade of F in course for cheating on exam

Exams?Blackboard – testing

center• Short answer

• Matching

• Multiple choice

• Essay questions

Objectives

• Students will be able to describe the nature and scope of Ecology

• Students will be able to explain the role of Evolution theory in Ecology

• Students will be able to describe how ecologists gain knowledge

Chap 1What is ecology?

Many definitions:

“Scientific study of the distribution and abundance of organisms”

(Andrewartha and Birch)

Another definition:

“study of the structure and function of nature”

(Odum)

Ecology tries to explain the patterns that you find in the

real world:

Why are plants and animals where they are, and how many are there in those locations?

Plants, animals, protists, monera, fungi

Soils, air, water

Ecology is a broad science:

Physiology, taxonomy, chemistry, geography, behavior, etc.

Populationecology

Populationgenetics

Community ecology

Landscape ecology

Systems ecology

Physiological ecology

Populationbiology

Why be an ecologist?Why be an ecologist?

Most ecologists develop a “love” for Most ecologists develop a “love” for their organism, for the their organism, for the environment, and for asking environment, and for asking questions about their system.questions about their system.

Types of Ecological Studies

• ObservationalObservational– DescriptiveDescriptive– Random sampling or replicationRandom sampling or replication– Describe some aspect of natural worldDescribe some aspect of natural world

Observational

• Based on Representative Samples

– Random sampling from “population of interest” to obtain “unbiased” information.

– Replication: Multiple individuals / areas observed to document variation.

Types of Ecological Studies

• Comparative studiesComparative studies– What is influence of factor(s)What is influence of factor(s)– Data from natural worldData from natural world

HotEnvironment

WarmEnvironment

ColdEnvironment

What is the effect of temperature on the abundance of ants ?

ComparativeStudy

Comparative Studies

• Purpose: To determine the influence of one or more “factors” on some aspect of the natural world.

• Compare samples from populations, communities, ecosystems – do they change with the factor?

Disadvantage of Comparative Studies

• Many environmental factors differ among any two natural communities.

• Difficult to know if observed differences in the “response” variable are caused by the “treatment” variable or by some other factor.

Types of Ecological Studies

• ExperimentalExperimental– Determine effect of treatmentDetermine effect of treatment– Randomize individuals or areasRandomize individuals or areas– Replication = many samplesReplication = many samples– ControlControl

HeatedEnvironment

CooledEnvironment

What is the effect of temperature on the

activity of ants ?

Random

Assignment

Observe

Compare

ControlledEnvironments

ExperimentalStudy

Experimental Studies

• Purpose: To obtain most definitive evidence that “treatment” causes “response”, Test Cause-Effect Hypotheses.

• Main Difference From Comparative Studies: Investigator imposes treatment on study subjects.

• Can be done in Lab or Field

Aquatic Snails in Indiana

Mark Pyron and Jayson Beugly

Ball State University

Department of Biology

Historic distributions

• Museum records– University Michigan– Ohio State University

• > 100 lots

• Photograph individuals in each collection

Current distributions

• Visit historic sites– 100+ sites revisited– 20 new sites

• Collect in all habitats

• Water quality: hardness, DO, pH, conductivity, Temp

Sites through-out Indiana: Eel River

Big Blue River at Edinburgh

E. Fork 14-mile Creek

E. Fork White River

Fall Creek in Indianapolis

Little Turkey Lake near Helmer

Ohio River at Aurora

Muscatatuck River

Campeloma decisum

Physa acuta

Lymnaea humilis

Elimia livescens

Pleurocera acuta

Bellamya chinensis

New Collection Results

• 15,227 individuals in 26 species

• 2.8 species per site

• 144 individuals per site

Status

• One extinction (Valvata bicarinata)

• 12 imperiled

• 3 vulnerable to extinction

• 9 widespread + abundant

Taxa with highest abundances • Elimia livescens• Physa spp.• Pleurocera acuta• Fossaria spp.• Pleurocera canaliculata• Stagnicola elodes• Lymnaea catascopium• Campeloma spp.

• 10,564• 1,769

• 990• 759• 279• 108• 103

• 96

Species Richness

Lakes in North have higher species richness

Abundance patterns

Wabash River mainstemhas highest abundances

Results

• Latitude important at regional scale

• Habitat variation and water chemistry important at local scale

Observational, comparative, or experiment?

Experimental Design: Part 1

Random Assignmentof Study Subjects /Areasto Treatment Groups

Replication: MultipleStudy Subjects Assignedto Each Treatment Group

Equivalent Groups:Similar as possibleBEFORE imposingtreatment.

Stronger evidence thatdifferences betweengroups are causedby treatment.

Experimental Design: Part 2

Control of all non-treatment factorsto be same for allexperimental groups

Comparison of groups that receiveddifferent treatmentsto determine response

Differences observedbetween groups caused by treatment, NOT other factors.

Differences observedbetween groups wouldNOT have happenedwithout treatment.

Limitations of Experiments

• Subjects in controlled experimental conditions may not respond the same as when they are in their natural setting (Less Realistic).

• Some subjects very difficult to study in controlled settings (Lions, Trees, Communities, Ecosystems)

Role of evolution theory in ecology

• 1. What is evolution?– Changes in populations of organisms over time– Includes changes in gene frequencies = genetic

Role of evolution theory in ecology

• 2. How does natural selection work?– Cruel world– Genetic variation– Differential survival and repro

• Genes for advantageous traits spread

• 3. Some characteristics (traits) are “best available” for survival and reproduction (NOT the “BEST”)

• In a given environment

Role of evolution theory in ecology

Evolution = change in organisms with generations

not changes in communities (= extinctions or more species)

Adaptation:allow organisms to survive + reproduce - design of organisms.

Darwin –– woodpecker example:

Woodpecker adaptationsBeak, tongue,

tail, toes

Natural selection

• Some individuals survive and produce more offspring than others.

• Their traits “work better” in that environment.

On what level does natural selection act?

• Individuals?

• Species or populations?

• What entity evolves over time?

Pioneering ecological study:

• Robert MacArthur

• 5 forest warblers found in same forest– How do they all live in same environment if

they are all same size and all eat insects?

MacArthur• Divided trees into zones

• Recorded time that 5 species spent in zones

• Birds divided tree into zones

• Appears to reduce competition

MacArthur results:

Further studies confirmed that competitionmaintains feeding zones experimentally:

Field studies can be combined with lab

experiments

• Answer more detailed questions– Field = natural settings– Lab = controlled environment

Ecologists use available tools

• Can include behavior + physiology,

• Or, geology + paleontology

• Etc., depending on the question