Category: Curriculum Map

Ecology

Ecology

All Materials © Cmassengale 

Ecology is the study of interactions between organisms (biotic part) and their nonliving environment (abiotic factors)

Biotic factors includes plants, animals, fungi, & microorganisms. They may be producers, consumers, or decomposers.

Abiotic factors include climate, soil, temperature, water, air, sunlight, humidity, pH, and atmospheric gases.

Habitat is the place a plant or animal lives, while its niche is its total way of life.

Life is organized into levels:

Organism (any single living thing)

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            Population (members of the same species living in one place)

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                    Community (all the populations living in an area)

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        Ecosystem (community living in a similar habitat such as a forest)

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Biomes (ecosystems covering wide areas & with similar climates & organisms)

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Biosphere ( all the living & nonliving things on earth)

Producers:

Make their own food through photosynthesis or chemosynthesis
Includes plants, algal protists, & some bacteria

Consumers:

Can’t make their own food
May be herbivores (feed only on plants), carnivores (feed only on animals), or omnivores (feed on plants & animals)

Decomposers:

Break down dead plants & animals (detritus)
Recycle nutrients
Called detritivores
Include fungi & bacteria

Sunlight is the ultimate energy for all life on earth, but only producers can get their energy directly from the sun.

Energyflowinecosystemimage

Trophic levels are feeding levels of producers & consumers in an ecosystem:

1st Trophic Level is producers that use sunlight directly
2nd Trophic Level includes herbivores that feed directly on plants
Higher Trophic Levels are carnivores feeding on each other

energypyramid

Food chains & food webs:

Chains show who eats whom in an ecosystem.
Webs are made up of several food chains.
Always begin with producers absorbing sunlight.
Producers store energy in the chemical bonds of the food they make.
Stored energy is passed to consumers when they eat producers or other consumers.
Some energy is lost at each trophic level as heat when consumers “burn” food during cellular respiration.
Both energy & nutrients must move through an ecosystem.

Three main elements that must move through an ecosystem:

Water
Carbon
Nitrogen

Water or Hydrologic Cycle:

Cells are 70 – 90% water
Water is needed for metabolic processes
Water is most important for terrestrial organisms because of desiccation (drying out)

Steps in the water Cycle:

Evaporation                                         Transpiration
(water loss from lakes, rivers, oceans…)          (water loss from plant leaves)

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Condensation
(water vapor forms clouds)

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Precipitation
(water returns to earth as sleet, rain, snow…)

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Surface Runoff
(returns water to bodies of water or to groundwater)

Carbon Cycle:

Consists of photosynthesis, cellular respiration, & decomposition
Begins with producers taking carbon dioxide from the air during photosynthesis
Carbon dioxide used in cellular respiration
Decomposing plants and animals return Carbon to the soil

Carbon Cycle Steps:

Plant leaves take carbon dioxide from air

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Plants store carbon in carbohydrates or starches
(photosynthesis)

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Plants & animals release carbon dioxide back into the air
(cellular respiration)

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Decomposers return carbon to environment
(decomposition)

Nitrogen:

Needed by all organisms
Used to make proteins & nucleic acids (DNA & RNA)
Air made up of 80% nitrogen
Only Cyanobacteria & Rhizobium bacteria can use nitrogen directly from the air (nitrogen fixation)
Bacteria found in the soil & on the roots of legumes (beans, peas …)

Steps in the Nitrogen Cycle:

Cyanobacteria & Rhizobium take nitrogen from air
(nitrogen fixation)

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Convert nitrogen gas into ammonia

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Nitrifying bacteria in soil change ammonia into nitrates

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Plants can absorb & use nitrates to make proteins

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Consumers eat plants & get proteins containing nitrogen

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Decomposers break down dead organisms & return nitrogen to air
(called ammonification)

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Anaerobic bacteria in soil release nitrogen from nitrates into air
(called denitrification)

Three main types of ecosystems:

Terrestrial (land)
Freshwater (rivers, ponds, lakes …)
Marine (oceans & seas)

Terrestrial ecosystems are divided into 7 biomes with similar climates & organisms

Seven Terrestrial Biomes:

Tropical Rain Forest (jungle)
Savanna (tropical grasslands)
Deserts
Grasslands
Deciduous Forest
Taiga (coniferous forest)
Tundra

Tundra:

Cold & dark most of the year
Includes the arctic
Permafrost is the top layer of soil that thaws & in which plants grow
No trees, but sedges & grass, mosses, & lichens
Many migratory animals
Lemmings & ptarmigans are year round residents
Approximately 20 cm annual rainfall

Tundra

Taiga:

  • Coniferous forest
  • Extends across northern Eurasia & North America
  • Contains conifers or evergreens (spruce, cedar, fir, pine …)
  • Needle like leaves withstand weight of snow
  • Bear, deer, moose, wolves, mountain lions …
  • Sequoia or redwood (largest conifer) grows here
  • Bristle cone pine oldest living conifer found here

Coniferous Forest

Temperate Deciduous Forest:

  • South of taiga in North America, eastern Asia, & Europe
  • High annual rainfall (75-150 cm)
  • Moderate temperatures
  • Well-defined seasons of about equal length
  • Trees loose leaves in winter (deciduous)
  • Show stratification (plant layers):
    1. Canopy – broad leaf deciduous trees forming uppermost layer
    2. Under story – shrubs
    3. Forest Floor – herbaceous plants
  • Songbirds, deer, rabbits, foxes, squirrels, frogs 7 toads, lizards …

Temperate Deciduous Forest

Tropical Rain forest:

  • Near equator
  • Warm climate (20 -25 degrees C)
  • Plentiful rainfall (190 cm/year)
  • Contains the greatest diversity of plants & animals
  • Insects, monkeys & apes, snakes, tropical birds, leopards…
  • Animals & plants brightly colored
  • Poor soil for agriculture

Rainforest

Grasslands:

  • Mostly grasses with a few trees due to less rainfall
  • Moderate climates
  • Good for agricultural crops
  • Grazing & burrowing animals dominate
  • Also called prairies

Grassland

Savanna:

  • Tropical grasslands
  • Warm climate & rainy season
  • Antelope, zebra, lions, wildebeests, hyenas, elephants…
  • Suffer from floods & drought

(26KB)

Deserts:

  • Low annual rainfall
  • Subject to strong winds
  • Days usually hot & nights cold
  • Sahara desert is without vegetation
  • Succulents such as cacti & other water storing plants
  • Most animals nocturnal
  • Lizards, snakes, roadrunners, insects, tarantula, hawks, rodents, coyotes…

Desert

Aquatic Biomes:

  • May be freshwater or saltwater
  • Wetlands near oceans have brackish water (mixture of fresh & salt waters)
  • Part of the part water or hydrologic cycle
  • Often polluted by man’s activities

Lakes & Rivers:

  • Freshwater
  • Oligotrophic lakes are nutrient poor (catfish, carp…)
  • Eutrophic lake are nutrient rich (trout, bass…)
  • Deep lakes have layers or strata where different plants & animals live
  • Phototropic organisms in upper layers for light
  • Estuary at mouth of river contains brackish water

Ocean Zones:

  • Intertidal zone
    1. Along shoreline
    2. Wave action
    3. Lots of light so many producers
    4. Starfish, sand dollars…
  • Neritic Zone
    1. Ocean water above continental shelf
    2. Coral reef found here
    3. Surrounds continents & receives light in upper layers
  • Oceanic Zone
    1. Beyond continental shelf
    2. Deepest area (up to 7 miles)
    3. Bottom doesn’t receive light so animals adapted to darkness (many produce their own light, feed on other animals…)
    4. Deepest area called abyss
    5. Upper area gets light & called the photic zone (lots of seaweed here)
    6. Floaters called plankton (microscopic organisms)
    7. Swimmers such as fish called nekton
    8. Bottom dwellers called benthos
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Effect of Solutions on Cells

 Effect of  Solutions on Cells

What happens when cells are place in different kinds of solutions

Plant cells placed in a hypertonic solution will undergo plasmolysis, a condition where the plasma membrane pulls away from the cell wall as the cell shrinks. The cell wall is rigid and does not shrink. 

   The Elodea cells  have been placed in a 10% NaCl solution. The contents of the cells have been reduced to the spherical structures shown.  

 

 

   Normal Elodea cells

 

 

Animal cells placed in a hypertonic solution will undergo crenation, a condition where the cell shrivels up as it loses water. Red blood cells in a hypotonic solution will swell and burst or lyse.

                               

 

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Dichotomous Keying

 

Dichotomous Keying

Introduction to Dichotomous Key Maker:

The identification of biological organisms can be greatly simplified using tools such as dichotomous keys.  A dichotomous key maker is an organized set of couplets of mutually exclusive characteristics of biological organisms.  You simply compare the characteristics of an unknown organism against an appropriate dichotomous key.  These keys will begin with general characteristics and lead to couplets indicating progressively specific characteristics. If the organism falls into one category, you go to the next indicated couplet.  By following the key and making the correct choices, you should be able to identify your specimen to the indicated taxonomic level.

Couplets can be organized in several forms.  The couplets can be presented using numbers (numeric) or using letters (alphabetical).  The couplets can be presented together or grouped by relationships.  There is no apparent uniformity in presentation for dichotomous keys.

Sample keys to some common beans used in the kitchen:

Numeric key with couplets presented together.  The major advantage of this method of presentation is that both characteristics in a couple can be evaluated and compared very easily.

 

 

 

 

1a. Bean round Garbanzo bean
1b. Bean elliptical or oblong Go to 2
2a. Bean white White northern
2b. Bean has dark pigments Go to 3
3a. Bean evenly pigmented Go to 4
3b. Bean pigmentation mottled Pinto bean
4a. Bean black Black bean
4b. Bean reddish-brown Kidney bean

 

Alphabetical key with couplets grouped by relationship.  This key uses the same couplet choices as the key above.  The choices within the first and succeeding couplets are separated to preserve the relationships between the characteristics.

 

 

A. Bean elliptical or oblong Go to B
   B.  Bean has dark pigments Go to C
            C.  Bean color is solid Go to D
            C.  Bean color is mottled Pinto bean
                     D.  Bean is black Black bean
                     D.  Bean is reddish-brown Kidney bean
   B.  Bean is white White northern
A. Bean is round Garbanzo bean

 

Rules for Using Dichotomous Keys: 

When you follow a dichotomous key, your task becomes simpler if you adhere to a few simple rules of thumb:

  1. Read both choices in a couplet carefully.  Although the first description may seem to fit your sample, the second may apply even better.
  2. Keep notes telling what sequence of identification steps you took.  This will allow you to double-check your work later and indicate sources of mistakes, if they have been made.
  3. If you are unsure of which choice to make in a couplet, follow both forks (one at a time).  After working through a couple of more couplets, it may become apparent that one fork does not fit your sample at all.
  4. Work with more than one sample if at all possible.  This will allow you to tell whether the one you are looking at is typical or atypical.  This is especially true when working with plants – examine more than one leaf, branch, cone, seed, flower,…etc.
  5. When you have keyed out an organism, do not take your effort as the final result.  Double check your identification scheme, using your notes.  Find a type specimen (if available) and compare your unknown to the type specimen.  If a type specimen is unavailable, find a good description of the indicated taxonomic group and see if your unknown reflects this description.
  6. When reading a couplet, make sure you understand all of the terms used.  The best keys will have a glossary of technical terms used in the key.  If a glossary is unavailable, find a good reference work for the field (textbook, biological dictionary,…etc.) to help you understand the term.
  7. When a measurement is indicated, make sure that you take the measurement using a calibrated scale.  Do not “eyeball” it or take a guess.

Exercise 1:

Using a container of beans, use one of the dichotomous keys above to identify the beans.  Glue the beans to the card provided and label them with their common name. Indicate what steps you followed to arrive at your answer.  Turn the card in to your instructor.  Compare your answers to the instructor’s descriptions and type specimen.

Exercise 2:

Obtain samples of the snack chips provided.  Develop a dichotomous key to identify the snacks.  In your notebook, keep track of the characteristics you used to differentiate between the different snack families.  What are the values of the characteristic for each snack food?

Exercise 3:

Use the dichotomous key to conifers provided below to identify conifers.

A Key to Selected North American Native and Introduced Conifers

 

 

01a Leaves needle-like Go to 02
01b Leaves flattened and scale-like Go to 27
02a Leaves are in clusters Go to 03
02b Leaves are borne singly Go to 15
03a Two to five leaves in a cluster Go to 04  Genus Pinus
03b More than five leaves in a cluster Go to 14
04a Leaves mostly 5 in a cluster White Pine (Pinus strobus)
04b Leaves 2 or 3 in a cluster Go to 05
05a Leaves mostly 3 in a cluster Go to 06
05b Leaves mostly 2 in a cluster Go to 08
06a Leaves twisted, less than 5 inches long Pitch Pine (Pinus rigida)
06b Leaves straight, more than 5 inches long Go to 07
07a Leaves 5-10 inches long, cones very thorny Loblolly pine (Pinus taeda)
07b Leaves mostly over 10 inches long, cones unthorned Longleaf pine (Pinus palustris)
08a Leaves mostly longer than 3 inches Go to 09
08b Leaves mostly shorter than 3 inches Go to 11
09a Leaves rigid, bark grayish Black pine (Pinus nigra)
09b Leaves narrower than 1.6mm; bark reddish brown or brown Go to 10
10a Cones thornless, twigs brown Norway pine (Pinus resinosa)
10b Cones thorny, twigs whitish Shortleaf pine (Pinus echinata)
11a Leaves mostly wider than 1.5 mm Go to 12
11b Leaves mostly narrower than 1.5 mm Go to 13
12a Leaves mostly longer than 35 mm Mugho pine (Pinus mugo)
12b Leaves mostly shorter than 35 mm Jack pine (Pinus banksiana)
13a

Twigs whitened

 Virginia pine (Pinus virginiana)
13b Twigs not whitened Scotch pine (Pinus sylvestris)
14a Leaves deciduous, clusters of 20-40 Larch (Larix sp.)
14b Leaves persistent, stiff, and four sided True cedar (Cedrus sp.)
15a Needles short and sharp Giant Sequioa  (Sequioadendron giganteum)
15b Needles longer than 12 mm Go to 16
16a Tiny pegs on twigs Go to 17
16b No pegs on twigs Go to 22
17a Pegs square, needles sharp Go to 18 Genus Picea
17b Pegs round, needles flat and blunt Hemlock (Tsuga sp.)
18a Leaves dark green or yellow green Go to 19
18b Leaves blue-green Go to 20
19a Branchlets droop Norway spruce (Picea abies)
19b Branchlets do not droop Red spruce (Picea rubens)
20a Leaves at right angles to stems Blue spruce (Picea pungens)
20b

Leaves point forward

 Go to 21
21a Leaves about 12 mm long, seed cones 15-32 mm in length, crown narrow and pointed Black spruce (Picea mariana)
21b Leaves about 19 mm long, seed cones 50 mm in length, spire-like crown

White spruce (Picea glauca)
22a Buds large and pointed Douglas fir (Pseudotsuga sp.)
22b Buds small and rounded Go to 23
23a Terminal buds round and clustered True fir (Abies sp.)
23b Terminal buds not clustered Go to 24
24a Needles white underneath Go to 25
24b Needles green underneath Go to 26  Genus Taxus
25a Needles pointed

Redwood (Sequoia sempervirens)
25b Needles blunt Hemlock (Tsuga sp.)
26a Leaves 18 mm long or less with inconspicuous midrib American Yew (Taxus canadensis)
26b Leaves 25 mm long or more with conspicuous midrib Japanese Yew (Taxus cuspidata)
27a All leaves short and sharp Giant Sequioa  (Sequioadendron giganteum)
27b Some leaves not sharp Go to 28
28a Cones round Go to 29
28b Cones not round Go to 31
29a Cones soft and leathery Juniper (Juniperus sp.)
29b Cones woody Go to 30
30a Cones under 12 mm in diameter False cypress  (Chamaecyparis)
30b Cones over 12 mm in diameter Cypress (Cuppressus)
31a Cones resemble rosebuds White cedar or arbor vitae (Thuja)
31b Cones resemble duck bills Incense cedar (Calocedrus)

 

Conifers to Identify:

1. Name: 2. Name:

3. Name: 4. Name:

5. Name: 6. Name:


7. Name: 8. Name:


9. Name: 10. Name:


11. Name: 12. Name:


13. Name: 14. Name:


15. Name: 16. Name:

Photos Copyright Nearctica.com

Click here for correct answers to conifer key

 

Ecology Study Guide

Ecology Study Guide

List several biotic factors in an ecosystem.
List several abiotic factors in an ecosystem.
What serves as the ultimate energy for all life on earth?
What is transpiration & what cycle is it a part of ?
Why are the Rhizobium bacteria beneficial to plants?
What is nitrogen fixation?
What is denitrification?
Where is the intertidal zone found & list several organisms that would be found there?
Name 3 types of consumers based on their eating habits.
What is detritus & why is it important?
What are trophic levels & give an example?
What is the term for an organism’s total way of life?
How does an animal’s habitat differ from its niche?
Compare & contrast biomes.
Describe estuaries.
How does an oligotrophic lake differ from a eutrophic lake?
What is brackish water & where would it be found?
Where is the neritic zone found & what organisms would be found there?
Where would benthos organisms be found? Give an example of such a dweller.

Describe abiotic & biotic factors for each of these biomes:

Tropical rain forest
Taiga
Tundra
Grassland
Savanna
Desert
Deciduous forest
Intertidal Zone
Neritic Zone
Oceanic Zone
Oligotrophic River
Eutrophic River
Estuary
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Egg Osmosis Sample 1 Lab

Osmosis through the Cell Membrane of an Egg

Introduction:
The cell or plasma membrane is made up of phospholipids and different types of proteins that move laterally. These include peripheral proteins, which are attached to the interior and exterior surface of the cell membrane. Integral proteins are embedded in the lipid bilayer. Attached to these integral proteins are carbohydrate chains. These carbohydrates may hold adjoining cells together, or act as sites where viruses or chemical messengers such as hormones can attach. Cell membranes are selectively permeable. They allow some substances to pass through, but not others. Small molecules that are usually nonpolar, such as oxygen, water, and carbon dioxide, easily move through the lipid bilayer. Larger molecules, such as glucose, the food for all living things, must seek aid from the carrier proteins in a process called facilitated diffusion. Facilitated diffusion is a process used for molecules that cannot diffuse rapidly through cell membranes. Integral proteins are used by calcium, potassium, and sodium ions to move through the cell membrane. The muscles and nerves use these ions.
Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. This difference in the concentration of molecules across a space is called a concentration gradient. Diffusion is a type of passive transport, meaning it does not require energy input by the cell. This type of transport and osmosis are the two processes used in this lab. Osmosis is the process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration. When the concentration of the solute is higher outside of the cell, it is known as a hypertonic solution. When the concentration of the solute is lower outside of the cell, it is known as a hypotonic solution.

Hypothesis:
The substance, syrup, which has a higher solute concentration than the interior of the eggs, will cause water to leave the eggs’ membrane; the other substance, distilled water, which has a lower solute concentration than the eggs’ interior, will cause liquid to enter the eggs’ membrane.

Materials:
The materials necessary for this lab are: two fresh eggs in their shells, a felt tip marker, 200mL graduated cylinder, five jars, clear Saran wrap, white vinegar, clear sugar syrup (Karo), distilled water, tap water, pencil, paper, eraser, computer, electronic scale, and a plastic tray.

Methods:
Day One: On day one, label the five jars, with the felt tip marker: one labeled vinegar, two labeled syrup, and two labeled distilled water. Also put the group number on each jar. Find the mass of each egg and record this information in the data table. Place the two eggs in the jar labeled vinegar. Add vinegar until both eggs are submerged by it. Cover the jar with the clear Saran wrap. Place the jar on the plastic tray and allow to set for 24 hours.

Day Two: On day two, observe what has happened to your eggs. Record this in a data table. Now that the eggs’ shells are dissolved, gently remove the eggs from the vinegar. Rinse each egg with tap water. Pat the eggs dry with paper towels and mass them separately on the electronic balance. Record this in the data table. Place the eggs in the jars labeled syrup. Add syrup to each jar (labeled egg 1 or egg 2) until the eggs are submerged in syrup. Loosely cover each jar with Saran wrap. Place the jars on the tray and allow them to soak for 24 hours.

Day Three: On day three, observe what has happened to the eggs and record this information in the data table. Carefully remove the eggs from the syrup and rinse them with tap water. Pat dry with paper towels. Using the electronic balance, find the mass of each egg separately and record these masses in the data table. Place the eggs in the jars labeled distilled water (labeled egg 1 and egg 2). Add distilled water to each jar until the eggs are covered. Cover the jars with the Saran wrap and allow them to sit on the tray for 24 hours.

Day Four: On day four, remove the eggs from the jars and record the eggs’ appearance. Mass each egg on the electronic balance. Record this in the data table. Dispose of the eggs in the container provided by the teacher.

Results:

Egg 1 Data Table

 

Substance egg submerged in Egg’s mass before placed in substance Egg’s mass after removed from substance Observations of egg before placed in solution Observations of egg after removed from substance
Vinegar 59.2 g 86.0 g The egg’s shell is intact and is included in the first mass. The egg’s shell dissolved and wasn’t included in the 2nd mass.
Syrup 86.0 g 53.2 g The egg is swollen and soft, yet firm to touch. The liquid inside the egg diffused into the syrup.
Distilled Water 53.2 g 86.5 g The egg has lost some of its firmness. The water diffused into the egg, increasing the egg’s mass.

 

Egg 2 Data Table

 

Substance egg submerged in Egg’s mass before place in substance Egg’s mass after removed from substance Observations of egg before placed in solution Observations of egg after removed from substance
Vinegar 58.8 g 85.6 g The egg’s shell is intact and is included in the first mass. The egg’s shell is mostly dissolved and so wasn’t included in 2nd mass.
Syrup 85.6 g 52.2 g The egg is rough to touch and feels rather sturdy. The liquid inside the egg diffused into the syrup.
Distilled Water 52.2 g 88.9 g The egg feels more fragile and lighter in weight. The water diffused into the egg increasing the egg’s mass.

 

 

 

 

Egg in Hypotonic Solution of Vinegar & Plasmolyzed Egg in Distilled Water Egg in Hypertonic Solution of Syrup

 

1. When the egg was place in the water, in which direction did the water molecules move? The water moved into the eggs from the surrounding environment.

2. On what evidence do you base this? The eggs’ masses had increased from the time they were placed in the water to when the eggs were removed.

3. How do you explain the volume of liquid remaining when the egg was removed from the syrup? The volume of the liquid remaining when the egg was removed from the syrup must have increased because the eggs’ masses had decreased. The liquid within the eggs left the eggs and diffused into the surrounding syrup.

4. When the egg was place in the water after being removed from the syrup, in which direction did the water move? The water moved into the eggs.

Error Analysis:
Several errors may have occurred during this lab. When finding the eggs’ masses, on each occasion, an error may have occurred. Mistakes may have been made when recording these masses on the data table. Some of the eggs’ shell may have been left on the eggs’ membranes and changed the outcome of this lab. When the eggs were rinsed, after being placed in the vinegar and syrup, a small amount of water could have entered through the membranes of the eggs, effecting their masses. These are just a few of the errors that may have taken place throughout the lab.

Discussion and Conclusion:
The hypothesis was correct. When the eggs were placed in the syrup, their masses decreased greatly. This shows that the interior of the eggs must have had a lower solute concentration than their surrounding environment of syrup. The water within the eggs left through the membrane and diffused into the syrup, decreasing its solute concentration. When the eggs were placed in the distilled water, their masses greatly increased. This shows that the interior of the eggs must have had a higher solute concentration than their surrounding environment of distilled water. The distilled water diffused into the eggs’ membrane, decreasing the interior of the eggs’ solute concentration.

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