Curriculum Map 74 - BIOLOGY JUNCTION

Nucleotide Model preap

Model of a Nucleotide

Introduction

Nucleotides consist of three parts — a pentose sugar, a nitrogen-containing base, and a phosphate group. A pentose sugar is a five-sided sugar. There are 2 kinds of pentose sugars — deoxyribose and ribose. Deoxyribose has a hydrogen atom attached to its #2 carbon atom (designated 2′), and ribose has a hydroxyl group atom there. Deoxyribose-containing nucleotides are the monomers of DNA, while Ribose-containing nucleotides are the monomers of RNA.

A nitrogen-containing ring structure is called a base. The base is attached to the 1′ carbon atom of the pentose. In DNA, four different bases are found — two purines, called adenine (A) and guanine (G) and two pyrimidines, called thymine (T) and cytosine (C). RNA contains The same purines, adenine (A) and guanine (G). RNA also uses the pyrimidine cytosine (C), but instead of thymine, it uses the pyrimidine uracil (U).

The Purines	The Pyrimidines

The combination of a base and a pentose is called a nucleoside. A phosphate group is attached to the 5′ carbon of the pentose sugar.

Objective

Students will construct a 3-dimensional model of a single nucleotide, the monomer of which nucleic acids are composed.

Materials

Various materials may be used for the atoms that make up a nucleotide such as styrofoam balls, plastic coke bottle caps, beads, etc. Bonds between atoms may be made from toothpicks, plastic stirring sticks, popsicle sticks, etc. Single & double bonds must be represented by the correct number of “sticks”. The atoms and bonds may NOT be made of any food item. Your model should be glued together to make the model rigid for hanging. Attach string and a label with the nucleotide’s name to your model. Models must be sturdy, light weight, and small enough to hang from the ceiling.

Color Code for atoms:

CARBON –	BLACK
HYDROGEN –	YELLOW
OXYGEN –	RED
NITROGEN –	BLUE

Structural Formulas of Nucleotides:

Uracil Nucleotide (Ribose ) & Thymine Nucleotide (Deoxyribose)

Adenine Nucleotide (Deoxyribose)

Cytosine Nucleotide (Deoxyribose)

Guanine Nucleotide (Deoxyribose)

Mollusk

Mollusks

All Materials © Cmassengale

Phylum Mollusca
Characteristics

Soft-bodied invertebrate covered with protective mantle that may or may not form a hard, calcium carbonate shell
Includes chitons, snails, slugs, clams, oysters, squid, octopus, & nautilus
Second largest animal phylum
Have a muscular foot for movement which is modified into tentacles for squid & octopus
Complete, one-way digestive tract with a mouth & anus
Have a fully-lined coelom
Cephalization – have a distinct head with sense organs & brain
Have a scraping, mouth-like structure called the radula
Go through free-swimming larval stage called trochophore

Trochophore Larva

Body organs called visceral mass lie below mantle
Have circulatory, respiratory, digestive, excretory, nervous, & reproductive systems
Bilaterally symmetrical
Most have separate sexes that cross-fertilize eggs
Gills between the mantle & visceral mass are used for gas exchange
Includes 4 classes — Polyplacophora (chitons), Gastropoda (snails, slugs, nudibranchs, conchs & abalone), Pelecypoda or Bivalvia (clams, oysters, & mussels), & Cephalopoda (squid, octopus, & nautilus)

SNAIL, CLAM, CHITON, & SQUID

Class Polyplacophora
Characteristics

All marine
Have a shell divided into 8 over-lapping plates
Live on rocks along seashore feeding on algae

CHITON

Class Gastropoda
Characteristics

Head has a pair of retractable tentacles with eyes located at the ends
Have a single shell or valve (snails) or none (slugs)
Known as univalves
Snails
* May be marine, freshwater, or terrestrial
* Aquatic snails breathe through gills & use their radula to scrape algae for food
* Terrestrial snails use their mantle cavity as a modified lung & saw off leaves
* Retreat into shell in dry periods & seals opening with mucus
* Have open circulatory system
* Secrete mucus & use muscular foot to move
* Land snails are hermaphrodites
* Aquatic snails have separate sexes
* Use internal fertilization

Slugs
* Live in moist terrestrial areas
* Lack a shell

SLUG

Pteropods
* Called “sea butterflies”
* Marine
* Have a wing-like flap for swimming

“SEA BUTTERFLY”

Oyster Drills
* Radula modified to drill into oyster shells

OYSTER DRILL

Nudibranch
* Marine slug
* Lacks shell

NUDIBRANCH

Class Bivalvia or Pelecypoda
Characteristics

Sessile or sedentary
Includes marine clams, oysters, shipworms, & scallops and freshwater mussels
Filter feeders
Have two-part, hinged shell (2 valves)
Have muscular foot that extends from shell for movement
Scallops clap valves together to move

Shell secreted by mantle & made of 3 layers — outer horny layer protects against acids, middle prismatic layer made of calcium carbonate for strength, & inner pearly layer next to soft body
Mantle secretes substance called “mother of pearl” to surround irritants like grains of sand
Oldest, raised part of shell called umbo
Powerful anterior & posterior adductor muscles open & close shell
Lack a distinct head
Have an incurrent & excurrent siphon that circulate water over the gills to remove food & oxygen

INTERNAL CLAM ANATOMY

Have heart & open circulatory system
Nervous system made of 3 pairs of ganglia, nerve cords, & sensory cells that detect light, chemicals, & touch
Separate sexes with external fertilization of eggs

Class Cephalopoda or Amphineura
Characteristics

Includes octopus, squid, cuttlefish, & chambered nautilus
All marine


NAUTILUS	OCTOPUS	SQUID

Most intelligent mollusk
Well developed head
Active, free swimming predators
Foot divided into tentacles with suckers
Use their radula & beak to feed
Closed circulatory system
Lack an external shell
Highly developed nervous system with vertebrate-like eyes
Separate sexes with internal fertilization

Squid
* Largest invertebrate is the Giant Squid
* Large, complex brain
* Ten tentacles with longest pair to catch prey
* Use jet propulsion to move by forcing water out their excurrent siphon
* Chromatophores in the skin can help change squid color for camouflage
* Can squirt an inky substance into water to temporarily blind predators
* Have internal shell called pen
* Female lays eggs in jellylike material & protects them until hatching

GIANT SQUID

Octopus
* Eight tentacles
* Similar to squid
* Crawls along bottom looking for prey

OCTOPUS

Chambered Nautilus
* Has an exterior shell
* Lives in the outer chamber of the shell
* Secretes gas into the other chambers to adjust buoyancy

NAUTILUS

Economic Importance of Mollusks

Used by humans for food
Pearls from oysters
Shells used for jewelry
Do crop & garden damage
Serve as intermediate hosts for some parasites such as flukes

Back

Natural Selection Activity

Survival of the Fittest

Introduction:

Within a population, organisms will vary. Charles Darwin stated that in the struggle for existence, those variant organisms that have favorable variations are “better adapted” to their environment and will survive and reproduce in greater numbers. Favorable variations may mean that they are faster, or stronger, or able to eat different types of food, or better camouflaged to avoid predators. In this lab you will simulate the effect of predation by a hawk on a large population of assorted mice. Your population of mice will consist of black, white, and speckled mice. You will represent the hawk.

Objectives:

–to simulate the effect of hawk predation on the appearance of mice
-to simulate the natural selection of traits

Materials:

large sheet of newspaper 4 hawks (students)
30 white mice (paper squares) 1 petri dish
30 speckled mice (paper squares)
30 black mice (paper squares)

Procedure:

Open your sheet of newspaper and place it on the lab table. This will serve as the environment for your mice.
Place the petri dish on the other side of the lab table. This will be the nest.
Select one person from your group to act as a hawk. This person should stand by the nest.
Spread the mice on their environment evenly.
The hawk now swoops over and has 1 minute to pick up as many mice as possible. The hawk may only pick up one mouse at a time, and must place it in their nest (a petri dish) before flying back to pick up another. The goal is to pick up as many mice as possible in the time period.
When the time is up record the number of mice left in the environment in the data table below.
Repeat this procedure for each person in the lab group or 4 times.
After all data is collected, construct a bar graph. Be sure to label the graph and its axes.
Data:

	White mice	Speckled mice	Black mice
Hawk #1
Hawk #2
Hawk #3
Hawk #4
Total

Conclusion:
Write a paragraph describing;

* the purpose of the lab

* what you thought the results would be

* what the results were (discussing numbers from data)

*how the mouse population and hawk population may change over time from natural selection

Moss & Fern

Mosses & Ferns

Kingdom Plantae
All Materials © Cmassengale

Seedless Nonvascular Plants

Includes mosses, liverworts, and hornworts
Lack vascular tissue (xylem & phloem) to carry water & food
Have a Sporophyte & Gametophyte stage known as alternation of generations
Gametophyte is dominant stage
Reproduce by spores

Division Bryophyta

Mosses:

Small, nonvascular land plants
No true roots, stems, or leaves
Class Musci
Most common bryophyte
Grow on moist areas (brick walls, as thick mats on forest floors, and on the shaded side of trees)
Some can survive periodic dry spells & revive when H2O becomes available
Must grow close together and must have H2O to complete their life cycle
Sperm swims to egg through drops of water during fertilization
H2O moves cell-to-cell by osmosis
Sphagnum moss is known for its moisture holding capacity, absorbing up to 20 times its dry weight with water.

MOSS SPOROPHYTES & FERN GAMETOPHYTES

LIFE CYCLE OF MOSSES:

Mosses alternate between a haploid (n) gametophyte stage & a diploid (2n) sporophyte stage
Gametophyte is the dominant generation

Moss Gametophyte	Moss Sporophyte

Called alternation of generations

The haploid gametophyte stage contains half the chromosome number & produces gametes (egg & sperm)
Gametophyte stage is dominant in the moss’s life cycle
Gametophytes are photosynthetic & have root-like rhizoids
The diploid sporophyte has a complete set of chromosomes & produces spores by meiosis
Sporophyte of a moss is smaller than, & attached to the Gametophyte
Sporophytes lack chlorophyll & depend on the photosynthetic gametophyte for food
Sporophyte has a long, slender stalk topped with a capsule
Capsule forms haploid (n) spores

Moss Capsules

Sexual Reproduction in Moss:

Mosses produce 2 kinds of gametes (egg & sperm)
Gametes of Bryophytes are surrounded by a jacket of sterile cells that keep the cells from drying out
Female gametes or eggs are larger with more cytoplasm & are immobile
Flagellated sperm must swim to the egg through water droplets for fertilization
Moss gametes form in separate reproductive structures on the Gametophyte — Archegonium & Antheridium

Archegonium	Antheridium

Each Archegonium forms one egg, but each Antheridium forms many sperm
Fertilization can occur only after rain when the Gametophyte is covered with water
Sperms swim to the egg by following a chemical trail released by the egg
A zygote (fertilized egg) forms that undergoes mitosis and becomes a Sporophyte
Cells inside mature Sporophyte capsule undergoes meiosis and form haploid spores
Haploid spores germinate into juvenile plants called protonema
Protonema begin the Gametophyte generation

Protonema of Funaria hygrometrica
Protonema

Spores are carried by wind & sprout on moist soil forming a new Gametophyte

Asexual reproduction in Mosses:

Asexual reproduction in moss may occur by fragmentation or gemmae
Pieces of a Gametophyte can break off & form new moss plants (fragmentation)
Gemmae are tiny, cup shaped structures on the Gametophytes
Raindrops separate gemmae from the parent plant so they can spread & form new Gametophytes

Gemmae cups

Uses for Moss:

Help decomposer dead logs
Serve as pioneer plants on bare rock or ground
Help prevent erosion
Provide shelter for insects & small animals
Used as nesting materials by birds & mammals
Sphagnum or peat moss forms peat bogs (wet ecosystem)
Peat is burned as fuel in some areas

Division Hepatophyta

Liverworts:

Nonvascular
Undergo alternation of generations with Sporophyte attached to Gametophyte
Gametophytes are green & leafy and the dominant generation

Liverwort

Need abundant water for fertilization
Reproduce by spores
Grow on moist rocks or soil
Reproduce asexually by gemmae and by growing new branches

Division Anthocerophyta

Hornworts:

Small, nonvascular bryophytes
Gametophyte leafy like liverworts
Archegonia & antheridia form inside the plant
After fertilization, zygotes develop into long, horn-shaped Sporophytes
Horn-shaped Sporophytes capable of photosynthesis so not completely dependent on Gametophyte

Hornwort

Seedless Vascular Plants

Includes club mosses, whisk ferns, horsetails, & ferns
Have specialized vascular tissues (xylem & phloem) to transport H2O, food, etc.
Have a Sporophyte & Gametophyte stage known as alternation of generations
Sporophyte is the dominant stage
Reproduce by spores

Division Psilophyta

Whisk Ferns:

Photosynthetic, aerial stem forks repeatedly to form a small twiggy bush
No true roots, stems, or leaves
Have horizontal, underground stems called rhizomes
Root-like structures called rhizoids anchor plant
Reproduce by spores & vegetatively from rhizomes
Only 2 living genera

Whisk Fern

Division Lycophyta

Club Mosses:

Low growing plants resembling pine trees
Have a club-shaped spore producing structure

Club Moss

Some like Lycopodium contain chemicals that burn quickly
Resurrection moss is green (after rains) when moist and brown when dry.

Resurrection Plant

Division Sphenophyta

Horsetails:

Equisetum called scouring rush is the only living species
Photosynthetic aerial stems & underground rhizomes
Stems contain silica & were once used to scrub pots
Reproduce by means of spores made in small cones at the tip of branches
In prehistoric times, some plants of this family grew to be large trees
Found in wetlands

Horsetail

Division Pterophyta

Fern Gametophyte:

Largest group of living seedless vascular plants
Live in moist habitats
Alternates between dominant Sporophyte stage & Gametophyte stage
Sporophyte stage has true roots, stems, & leaves
Produce spores on the underside of leaves

Leaves are called fronds & are attached by a stem-like petiole

FERNS

Fern Life Cycle:

Spores produced on underside of fronds in clusters of sporangia called sori
Spores undergo meiosis, are spread by wind, & germinate on moist soil to form prothallus
Prothallus begins the Gametophyte stage
Mature Gametophytes are small, heart-shaped structures that live only a short time
Male antheridia & female archegonia grow on the prothalli
Sperm must swim to the egg to fertilize it & developing embryo becomes the Sporophyte generation
Newly forming fronds are called fiddleheads & uncurl

Uses for Ferns:

Prevent erosion
Fiddleheads serve as food
Ornamental plants
Formed coal million of years ago

BACK

Natural Selection Peanut Activity

Natural Selection Within a Species

Introduction:

Natural selection is the evolutionary process by which the most adaptable individuals survive. An adaptation is an inherited variation that helps an organism to survive. When the organism survives, its chances of reproduction are increased as well as its ability to pass on its inherited traits. All members of a species are different from one another. In this activity, you will investigate two variations among peanut plants — length of shell and number of seeds per shell. Most shells contain a certain number of seeds which is an adaptation to its survival.

Objective:

Students will investigate natural selection in peanuts.

Materials:

50 peanuts in shells, metric ruler, pencil, graph paper

Procedure:

Count out 50 peanuts in their shells.
Use a metric ruler to measure the length of each shell in millimeters. Put a check mark in Table 1 in the space indicating the length of the shell.
Open the shell and count the number of seeds inside. Put a check mark in Table 2 in the space next to the number of seeds that you counted.
Repeat steps 1 – 3 for the other 49 peanuts.
Set up two bar graphs using the headings from each table as the axes for each graph.
Plot a bar graph from the data in each table.

Data:

Table 1

Length of Shell (mm)	Number of Shells
5-10
10-15
15-20
20-25
25-30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75

Table 2

Number of Seeds Per Shell	Number of Shells
1
2
3

Title: ________________________________________________________

Questions:

What is the most common length of the shells you measured?
What was the most common number of seeds in the peanut shells that you opened?
What might happen if each shell contained fewer than normal seeds and why?
What might happen if each shell contained more than the normal number of seeds and why?
Was there a relationship between the most common length of shells and the number of seeds they contained? Explain your answer.
Write 1-2 paragraphs explaining how shell length and seed number in peanuts illustrates natural selection within this species.