Category: Curriculum Map

Echinoderm

Echinoderms

All Materials © Cmassengale  

Phylum Echinodermata
Characteristics

  • All marine
  • Known as spiny-skinned animals
  • Endoskeleton known as the test is made of calcium plates or ossicles with protruding spines
  • Includes sea stars, brittle stars, sand dollars, sea urchins, & sea cucumbers
  • Undergo metamorphosis from bilateral, free-swimming larva to sessile or sedentary adult
  • Larval stage known as dipleurula or bipinnaria
  • Adults have pentaradial ( 5 part) symmetry
  • Lack segmentation or metamerism
  • Coelomate
  • Breathe through skin gills as adults
  • Capable of extensive regeneration


Bipinnaria Larva

  • Ventral (lower) surface called the oral surface & where mouth is located
  • Dorsal (upper) surface known as aboral surface & where anus is located
  • Have a nervous system but no head or brain in adults
  • No circulatory, respiratory, or excretory systems
  • Have a network of water-filled canals called the water vascular system to help move & feed
  • Tube feet on the underside of arms help in moving & feeding
  • One-way digestive system consists of mouth with oral spines, gut, & anus
  • Deuterostomes (blastopore becomes the anus)
  • Separate sexes
  • Reproduce sexually & asexually
  • Includes 5 classes:
    * Crinoidea – sea lilies & feather stars
    * Asteriodea – starfish
    * Ophiuroidea – basket stars & brittle stars
    * Echinoidea – sea urchins & sand dollars
    * Holothuroidea – sea cucumbers

Class Crinoidea
Characteristics

  • Sessile
  • Sea lilies & feather stars

 


FEATHER STAR
SEA LILY

 

  • Have a long stalk with branching arms that attach them to rocks & the ocean bottom
  • Can detach & move around
  • Mouth & anus on upper surface
  • May have 5 to 200 arms with sticky tube feet to help capture food (filter feeders) & take in oxygen
  • Common in areas with strong currents & usually nocturnal feeders

Class Asteroidea
Characteristics

  • Usually sedentary along shorelines
  • Starfish or sea stars
  • Come in a variety of colors
  • Prey on bivalve mollusks such as clams & oysters


Starfish Feeding on Clam

  • Have 5 arms that can be regenerated
  • Arms project from the central disk
  • Mouth on oral surface (underside)


STARFISH

Class Ophiuroidea
Characteristics

  • Largest class of echinoderms
  • Includes basket stars & brittle stars

 


BASKET STAR
BRITTLE STAR

 

  • Live on the ocean bottom beneath stones, in crevices, or in holes
  • Have long, narrow arms resembling a tangle of snakes
  • Arms readily break off & regenerate
  • Move quicker than starfish
  • Feed by raking in food with arms or trapping it with its tube feet

Class Echinoidea
Characteristics

  • Includes sea urchins & sand dollars

 


SEA URCHIN
SAND DOLLAR

 

  • Internal organs enclosed by endoskeleton or test made of fused skeletal plates
  • Body shaped like a sphere (sea urchin) or a flattened disk (sand dollar)
  • Lack arms
  • Bodies covered with movable spines
  • Have a jawlike, crushing structure called Aristotle’s lantern to grind food
  • Use tube feet to move
  • Sea Urchins:
    * Spherical shape
    * Live on ocean bottom
    * Scrape algae to feed
    * Long, barbed spines make venom for protection
  • Sand Dollars:
    * Flattened body
    * Live in sand along coastlines
    * Shallow burrowers
    * Have short spines

Class Holothuroidea
Characteristics

  • Includes sea cucumber


SEA CUCUMBER

  • Lack arms
  • Shaped like a pickle or cucumber
  • Live on ocean bottoms hiding in caves during the day 
  • Have a soft body with a tough, leathery outer skin
  • Five rows of tube feet run lengthwise on the aboral (top) surface of the body
  • Have a fringe of tentacles (modified tube feet) surrounding the mouth to sweep in food & water
  • Tentacles have sticky ends to collect plankton
  • Show bilateral symmetry
  • Can eject parts of their internal organs (evisceration) to scare predators; regenerate these structures in days

Structure & Function of Starfish
Body Plan

  • Range in size from 1 centimeter to 1 meter
  • Mouth located on oral surface (underside)
  • Have an endoskeleton made of calcium plates
  • Sharp, protective spines made of calcium plates called ossicles found under the skin on the aboral (top) surface


ABORAL SURFACE

  • Have pedicellariae or tiny, forcep-like structures surrounding their spines to help clean the body surface

Water Vascular System

  • Network of canals creating hydrostatic pressure to help the starfish move


WATER VASCULAR SYSTEM

  • Water enters through sieve plate or madreporite on aboral surface into a short, straight stone canal
  • Stone canal connects to a circular canal around the mouth called the ring canal
  • Five radial canals extend down each arm & are connected to the ring canal
  • Radial canals carry water to hundreds of paired tube feet


TUBE FEET

  • Bulb-like sacs or ampulla on the upper end of each tube foot contract & create suction to help move, attach, or open bivalves
  • Rows of tube feet on oral surface (underside) are found in ambulcaral grooves under each arm


Tube Feet in Ambulcaral Grooves

Feeding & Digestion

  • Tube feet attach to bivalve mollusk shells & create suction to pull valves apart slightly
  • Starfish everts (turns inside out) its stomach through its mouth & inserts it into prey
  • Stomach secretes enzymes to partially digest bivalve then stomach withdrawn & digestion completed inside starfish

Other Body Systems

  • No circulatory, excretory, or respiratory systems
  • Coelomic fluid bathes organs & distributes food & oxygen
  • Gas exchange occurs through skin gills & diffusion into the tube feet
  • No head or brain
  • Have a nerve ring surrounding the mouth that branch into nerve cords down each arm
  • Eyespots on the tips of each arm detect light
  • Tube feet respond to touch

Reproduction

  • Separate sexes
  • Two gonads (ovaries or testes) in each arm produce eggs or sperm
  • Have external fertilization
  • Females produce up to 200,000,000 eggs per season
  • Fertilized eggs hatch into bipinnaria larva which settles to the bottom after 2 years & changes into adult
  • Asexually reproduce by regenerating arms
BACK

 

Echinoderm Study Guide B1

Echinoderm Study Guide

 

Know the answers to the following:

 

A water vascular system is a trait of?
Clams are the basic food for what echinoderm?
A sea star feeds by extending what?
A sea star’s endoskeleton is made of what type of plates?
What around the mouth of a starfish helps coordinate its movements?
Tube feet  are part of what echinoderm system?
The blastopore becomes the anus in what type of organism?
Are chordates & echinoderms protostomes or deuterostomes?
Echinoderms like the sea urchin have what type of symmetry?
Are echinoderms fast or slow moving organisms?
How do echinoderms move?
Echinoderm larva have what type of symmetry?
What are the muscular sacs that force water through the water vascular system called?
In what phylum are sea squirts or tunicates?
Tunicates have a leathery what?
What animals are in the class Ophiuroidea?
How do basket stars & brittle stars differ?
What is the purpose of spines on a brittle stars arms?
Name an adult echinoderm with bilateral symmetry.
Do humans have a tail at any point during their development?
What was the function of gill slits in early chordates?
What is the flexible tube below the nerve cord in chordates called?
Where are lancelets usually found?

Be able to label the parts of the water vascular system of a starfish.

DNA Code for Insulin

 

DNA’s Instructions for Insulin  

 

Introduction:

Below are two partial sequences of DNA bases (shown for only one strand of DNA)  Sequence 1 is from a human and sequence 2 is from a cow.  In both humans and cows, this sequence is part of a set of instructions for controlling the production of a protein.  In this case, the sequence contains the gene to make the protein insulin.  Insulin is necessary for the uptake of sugar from the blood.  Without insulin, a person cannot use digest sugars the same way others can, and they have a disease called diabetes.

Materials:

paper, pencil, codon table

Procedure:

  1. Using the DNA sequence given in table 1, make a complimentary RNA strand for  the human.  Write the RNA directly below the DNA strand (remember to substitute U’s for T’s in RNA).
  2. Repeat step 1 for the cow.  Write the RNA directly below the DNA strand in table 2.
  3. Use the codon table in your book to determine what amino acids are assembled to make the insulin protein in both the cow and the human.   Write your amino acid chain directly below the RNA sequence.

Table 1 

 

Sequence 1 ­ Human
DNA C C A T A G C A C G T T A C A A C G T G A A G G T A A
RNA
Amino Acids

 

Table 2

Sequence 1 ­ Cow
DNA C C G T A G C A T G T T A C A A C G C G A A G G C A C
RNA
Amino Acids

Analysis:

1. The DNA sequence is different for the cow and the human, but the amino acid chain produced by the sequence is almost the same.  How can this happen?

 

 

2. Diabetes is a disease characterized by the inability to break down sugars. Often a person with diabetes has a defective DNA sequence that codes for the making of the insulin protein. Suppose a person has a mutation in their DNA, and the first triplet for the gene coding for insulin is C C C  (instead of C C A).   Determine what amino acid the new DNA triplet codes for.    Will this person be diabetic?

 

3. What if the first triplet was C A A ?

 

4. How is it that a code consisting of only four letters, as in DNA ( A, T, G, C ) can specify all the different parts of an organism and account for all the diversity of organisms on this planet?

 

 

DNA sequences are often used to determine relationships between organisms.  DNA sequences that code for a particular gene can vary widely.  Organisms that are closely related will have sequences that are similar. Below is a list of sequences for a few organisms:

 

Human CCA   TAG   CAC   CTA
Pig CCA   TGG   AAA   CGA
Chimpanzee CCA   TAA   CAC   CTA
Cricket CCT   AAA   GGG   ACG

 

5. Based on the sequences, which two organisms are most  closely related?

 

6. An unknown organism is found in the forest, and the gene is sequenced, and found to be   C C A  T G G  A A T  C G A  ,  what kind of animal do you think this is?

 

 

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)

¯

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

 ¯

                    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)

     ¯                                ¯

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

¯

Plants store carbon in carbohydrates or starches
(photosynthesis)

¯

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)

¯

Convert nitrogen gas into ammonia

¯

Nitrifying bacteria in soil change ammonia into nitrates

¯

Plants can absorb & use nitrates to make proteins

¯

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
BACK

 

DNA Replication Lab

Modeling DNA Replication

 

Introduction

Within the nucleus of every cell are long strings of DNA, the code that holds all the information needed to make and control every cell within a living organism. DNA, which stands for deoxyribonucleic acid, resembles a long, spiraling ladder. It consists of just a few kinds of atoms: carbon, hydrogen, oxygen, nitrogen, and phosphorus. Combinations of these atoms form the sugar-phosphate backbone of the DNA — the sides of the ladder, in other words.

Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder. (It takes two bases to form a rung — one for each side of the ladder.) A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide. Nucleotides are abundant in the cell’s nucleus. Nucleotides are the units which, when linked sugar to phosphate, make up one side of a DNA ladder.

During DNA replication, special enzymes move up along the DNA ladder, unzipping the molecule as it moves along. New nucleotides move in to each side of the unzipped ladder. The bases on these nucleotides are very particular about what they connect to. When the enzyme has passed the end of the DNA, two identical molecules of DNA are left behind. Cytosine (C) will “pair” to guanine (G), and adenine (A) will “pair” to thymine (T). How the bases are arranged in the DNA is what determines the genetic code.

 

When the enzyme has passed the end of the DNA, two identical molecules of DNA are left behind. Each contains one side of the original DNA and one side made of “new” nucleotides. It is possible that mistakes were made along the way — in other words, that a base pair in one DNA molecule doesn’t match the corresponding pair in the other molecule. On average, one mistake may exist in every billion base pairs. That’s the same as typing out the entire Encyclopedia Britannica five times and typing in a wrong letter only once!

Objectives

The replication of DNA before cell division can be shown using paper templates for the components of DNA nucleotides.

Materials

  • Cut Outs of basic subunits of DNA
  • Colors or markers
  • Scissors
  • Tape or glue
  • Paper & pencil

Procedure:

  1. Cut out all of the units needed to make the nucleotides from the handout provided.
  2. Color code the Nitrogenous bases, phosphorus, and deoxyribose sugar as follows —
    Adenine = red, Guanine = green, Thymine = yellow, Cytosine = blue, Phosphate = brown, and Deoxyribose = purple.
  3. Using the small squares and stars as guides, line up the bases, phosphates and sugars.
  4. Now glue the appropriate parts together forming nucleotides.
  5. Construct DNA model using the following sequence to form a row from top to bottom – cytosine (topmost), thymine, guanine, and adenine (bottommost).
  6. Let this arrangement represent the left half of your DNA molecule.
  7. Complete the right side of the ladder by adding the complementary bases. You will have to turn them upside down in order to make them fit.
  8. Your finished model should look like a ladder.
  9. To show replication, separate the left side from the right side, leaving a space of about 6-8 inches.
  10. Use the remaining nucleotides to complete the molecule using the left side as the base.
  11. Build a second DNA model by adding new nucleotides to the right half of the original piece of the molecule.
  12. Tape the nucleotides together to form 2 complete DNA ladders.

Questions

1. Of the 4 bases, which other base does adenine most closely resemble?

2. List the 4 different nucleotides.

3. Which 2 molecules of a nucleotide form the sides of a DNA ladder?

4. If 30% of a DNA molecule is Adenine, what percent is Cytosine?

5. What does the term replication mean?

6. What is another name for adenine and three phosphate molecules attached to it?