Ch. 1  Introduction to Ecology

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I.                     Intro - ecology vs. environment – earth slide show

A.      Overwiew

1.  Huge range in ecological study – individuals -àbiosphere (slide1)

2.  “Ecology” from Greek - oikos, meaning house

a.       ecology - science that examines living organisms, their living environment and the relationships between all; or, study of relationships between orgs and env.

b.       because it includes human influences, ecology is critical for helping conservation movement, but ecology is NOT the environment

c.       examples of ecological studies (slide 8)

1.       population regulation by predators

2.       influence of animals on soil fertility

3.       evolutionary responses of microbes to environmental contaminants

4.       influence of environment on migrating animals etc.

5.       management of the earth’s biotic and abiotic resources will sustain human quality of life

B.      Ecological systems can be large or small (slide 2-7)

1.       an ecological system may be an organism, population, community, an ecosystem or biosphere

2.       human defined

3.       hierarchy

a.       organism - bounded by membrane or other covering that can exchange materials (slide 9)

b.       organisms acquire energy and nutrients from the environment, rid wastes

c.       ecosystems are complex systems - humans can’t effectively create one for a long period of time

d.       populations are the units of evolution, ecology is evolution in action - organisms and their adaptations.

e.       communities are groups of interacting pops

f.         biosphere- all ecosystems linked together

1.       biosphere includes all environments and organisms of earth

2.       biosphere linked by movement of energy and nutrients and of wind (air) and water

3.       eg.  industrial and agricultural wastes link the globe

4.       populations interact in communities - predator prey, plants and pollinators

C.      Ecologists study nature from several perspectives (slide 9)

1.       all approaches have intersections - organismal ecologists often study role of form, physiology and behavior in survival – eg. Polar bears

a.  distributional limits

b.  adaptations - interactions w/environment

1.  adaptations result from survival of individuals with some characteristics over others- intersects with population ecologists

D.      Plants, animals and microbes all play different roles in ecological systems (slide 10)

1.       4.5 bya life began - prokaryotes (bacteria)

a.       1.5 bya eukaryotes (protists, plants, animals, fungi)

b.       it took photosynthesizers 3 billion years to produce enough O2 for multicelled organisms (slide 11)

2.       Plants use energy of sunlight to produce organic matter

a.       use roots to absorb nutrients and water from soil

b.       some are epiphytes (slide 12, 13)

3.       Animals are heterotrophs -feed on other organisms (sl 14)

a.       exchange surfaces inside body, unlike plants

b.       development of skeletal and muscular systems for movement

4.       Fungi - highly effective decomposers (slide 15)

a.       bodies of fungi are hyphae- hairlike structures that are often single cell in diameter

b.       reproduce asexually from spores

c.       mushrooms are reproductive structures like flowers

d.       penetrate deeply, decompose plant material

e.       digest food externally by secreting acids and enzymes then absorbing dissolved nutrients

f.         hugely important recyclers

5.       Protists - one-celled organisms, ancestors to multicelled organisms (slide 16)       

a.       one -celled algae, Ps (photosynthesis) basis of food chain in ocean (plankton)

b.       multicelled algae - seaweed

c.       amoebas, paramecium - animal like and important in food chains

6.       bacteria ((sl 17))

a.       energy transformations - single cell, no nucleus and chromosomes

1.       some are photosynthesizers

2.       some can assimilate nitrogen

3.       Some can live anaerobically etc

7.  there are many different types of relationships in nature – btn organisms, eg., competition

      a.   competitive exclusion hypothesis

8.  Habitat - where an organism lives in nature

9.  niche (slide 18)

- how an organism makes its living and range of conditions it can tolerate - role in ecosystem - how it makes its living consider light, pressure, temp, O2, viscosity, salinity

a.  MacArthur – warblers – niche partitioning

b.  Morse – refined MacArthurs work – common in the scientific process

10.  vegetation change modeling- Margaret Davis studies Quarternary period (Slide 20) –

      a.  pollen in lake sediments

                  1.  very useful in predicting and understanding ecological response to global climate change

E.      Ecologists use the scientific method to study the natural world

1.       observation and description is one method used

2.       development of hypotheses, or educated guesses

3.       testing of hypotheses, with experiments or observations

4.       The “scientific method”

a.       observations about a phenomenon

b.       often involves a pattern that is repeated in nature - eg.   in tropics, more species than in temperate  regions

c.       hypothesis - explanation that accounts for the observation

d.       if - then relationship - based on your hypothesis, make a prediction that you can then test in an experiment

e.       controls- reproduce all aspects of an experiment except the experimental variable - the variable of interest

F.      Humans are prominent part of the biosphere

1.       > 6 billion people on earth right now.

a.       huge impacts on other systems

b.       “fouling our own nest”

2.       to deal with these issues, we use ecological principles

a.       Nile perch - in 1950s and 60s, Nile perch were introduced in Lake Victoria to provide extra food and $ for residents (fig. 1.21)

1.        perch ate all the native cichlids, lower on the food chain - less biomass harvested

2.       cichlids had no escape behaviors and were decimated, many species driven to extinction

3.       perch must be smoked rather than sundried, so local forests were cut to provide fuel

b.       sea otter fig. (1.22)

1.       human fishing seems to have cause seal and sea lion population to crash

2.       killer whales are going after otters

3.       fewer otters allows boom in sea urchins which eat more kelp

4.       kelp are important feeding grounds for many species of fish and invertebrates

G.     Incredibly complex systems - often we only know a part of a system, and cause more destruction with incomplete knowledge -

1.       e.g.  - mongooses in HA

2.       pesticide use

3.       etc.

j.         Some success stories too –

1.       mosquitoes in Tahoe

2.       California condor

3.       TRPA?

Ch. 1 Lesson Objectives/review questions

1. Define ecology.  Give an example of an ecological study.

2. What is an adaptation?  How is it important in ecology?

3. Distinguish between levels in biology’s hierarchy- for example, between a community and a population.

4. describe MacArthur’s work with warblers and what ecological concept it helped elucidate (shed light on) for us?

5. Distinguish between an organism’s habitat and its niche, and give an example using MacArthurs warblers.

6.  What are the 5 kingdoms of life, and what characterizes the organisms in each Kingdom?

7. Describe the main steps involved in the scientific method.

8. Of what importance is a "control" in a scientific experiment?

9.  How have humans used ecological principles to try to manage natural systems?  (Be able to relay a success story as well as a failure).