Saturday, May 9, 2009

Characteristics of the Major Animal Phyla

Bios,

After our discussion after the mock test I thought that I would post the hastily written notes from the board with a few additions. So here is a description of selected (meaning not all) Phyla and Classes of Kingdom Animalia.

Kingdom Animalia: Animals are multicellular eukaryotes that obtain their food by ingestion.

Phylum Porifera (the sponges): No symmetry, no true tissues, filter feeders, and sessile. Mostly marine freshwater. The simplest form of animal life.

Phylum Cnidaria: Radial symmetry, tissues, mouth, simple gut, and nerve net. Free-living form is the medusa and sessile form the medusa.
Class Scyphozoa – Marine free-living, jelly fish.
Class Anthozoa – Marine sessile, sea anemone and corals.

Phylum Platyhelminthes: Ribbon-like soft bodied animals with bilateral symmetry, simple organs, central nervous system, cephalization, free-living and parasitic. Examples - flatworms, tapeworms, and flukes.

Phylum Annelida: Soft segmented bodies with bilateral symmetry, cephalization, closed circulatory system, free-living, marine, freshwater, and soil. Some parasitic. Examples - earthworms and leeches.

Phylum Mollusca: Soft bodies with bilateral or asymmetry, muscular foot and most have a shell. Most are marine but many live in freshwater and on land. Examples – snails, slugs, clams, oysters, squid, and octopus.
Class Polyplacophora (many/plate/bearer) – bilateral symmetry, eight shell plates, marine, foot for locomotion. Example - chiton
Class Gastropoda (stomach/foot) – asymmetric body with spiral shell tough the shell may be absent, foot for locomotion. Examples – snails, slugs.
Class Cephalopoda (head/foot) – marine, foot modified into tentacles, big eyes. Examples – squid and octopus.
Class Bivalvia (two/shells)– marine and freshwater, two shells, filter feeder. Example - clams, oysters, mussels

Phylum Arthropoda: Two out of three organisms on Earth are arthropods and they are found in every ecosystem! Jointed appendages, exoskeleton, segmented body, compound eye (in most), and many other well developed sensory organs.
Class Arachnida – simple eyes (8), no antennae, two body segments (head and cephalothorax), eight legs. Examples – spiders, ticks, scorpions, and mites.
Class Crustacea – compound eyes, two pair of antennae, multiple body segments, multiple legs, mostly marine. Examples – lobsters, crabs, shrimp, copepods, barnacles.
Class Diplopoda – multiple segments each with two pair of legs, herbivore. Example – millipedes.
Class Chilopoda - multiple segments each with one pair of legs, carnivore. Example – centipedes.
Class Insecta – compound eyes, three segments (head, thorax, abdomen), usually with two pair of wings, six legs, terrestrial, complete and incomplete metamorphosis. Examples – flies, bees, dragonflies, wasps.

Phylum Echinodermata: Radial symmetry, sessile or sedentary, endoskeleton, marine. Examples – starfish, sea urchins, sea cucumbers, sand dollars.

Phylum Chordata: Identified by these structures present during embryo stage - notocord, dorsal nerve cord, gill slits.
Subphylum Vertebrata: Animals with backbones.
Class Agnatha – jawless, skeleton of cartilage, notochord, marine and freshwater. Example – lamprey.
Class Chondrichthyes – Marine, skeleton of cartilage, jaws, paired fins, streamlined bodies, internal fertilization, oviparous and ovoviviparous, cloaca. Examples – sharks, rays.
Class Osteichthyes – Freshwater and marine, skeleton of bone, jaws, paired fins, operculum, swim bladder, great majority have external fertilization, oviparous, cloaca. Examples – trout, tuna, goldfish, koi.
Class Amphibia – four legs, scaleless skin, terrestrial (but needs water to reproduce), ectotherm (cold blooded), oviparous, jelly-like egg, cloaca, lungs, metamorphosis. Examples – salamanders, frogs, newts, toads.
Class Reptilia – four legs, scaly skin, primarily terrestrial, ectotherm, lays eggs on land, leathery shelled egg, oviparous cloaca. Examples – lizards, snakes, turtles, crocodiles.
Class Aves – Feathers, forelimbs modified into wings, acute vision, endothermic (warm blooded), internal fertilization, hard shelled eggs, cloaca. Examples – robin, penguin, bald eagle.
Class Mammalia – Hair, endothermic (warm blooded), mammary glands, internal fertilization, most viviparous (some oviparous), large brain, differentiated teeth. Examples – human, bear, kangaroo, platypus, shrew, blue whale.

Have fun with this. It could help on a few questions. Be sure to write, I will be monitoring the blog.

Mr. Baker

Friday, May 8, 2009

Photosynthesis Animations

Bios,

Here are a few links to photosynthesis animations that may help you remember how it works.

Light Reactions:
http://www.stolaf.edu/people/giannini/flashanimat/metabolism/photosynthesis.swf
http://www.cnr.vt.edu/DENDRO/forestbiology/photosynthesis.swf
http://www.youtube.com/watch?v=eY1ReqiYwYs
http://bcs.whfreeman.com/thelifewire/content/chp08/0802002.html

Dark Reactions:
http://bcs.whfreeman.com/thelifewire/content/chp08/0802003.html
http://www.metacafe.com/watch/yt-mHU27qYJNU0/the_calvin_cycle_or_dark_reactions_photosynthesis/

By the way, follow this lnk to a good site that reviews many topics covered in class.
http://bcs.whfreeman.com/thelifewire/

Feel free to post questions to me as comments to this blog.

Mr. Baker

Thursday, May 7, 2009

Comments on AP Labs

Bios,

Some of you have expressed an interest in reviewing labs we did not perform in class. I have found a web site that has very good summaries of every lab with a self-quiz section. Check this out - http://www.phschool.com/science/biology_place/labbench/ . I think you will find it helpful.

If you look over the labs you will see that we have done labs 1, 2, 3, 7, and 8. We did a couple of others that are not AP Labs and because many of you take biotechnology, I did not do lab 6. Of the labs on the Pearson web site be certain to go through 4, 5, and 12. All have been on past exams and each do a good job reinforcing concepts we covered in class. However, this web site is easy to use and you should go through them all for review purposes.

In class tomorrow we will be looking at the immune response and Saturday is the mock exam.

Mr. Baker

Monday, May 4, 2009

Human Chimp Homology

Bios,

The next few posts are presented to help you prepare for the AP exam. This first post addresses the homologies between humans and chimps. Recall that homologies are traits that are derived from the same ancestral form - they have a shared ancestry.

First of all, here is a brief timeline:
40 mya - primates diversify
15 mya - the great apes (Hominidae) diverge from the lesser apes
10 mya - the chimp human line diverges from the gorilla line
7 mya - the line that leads to humans diverges from chimps
4.4 mya - hominin bipedalism

Second, many of the human/chimp homologies relate to their arboreal origin.
Forward facing eyes
Stereo vision
Grasping hands, opposable thumb
Sensitive, dexterous fingers with nails rather than claws
Fully rotating shoulder
Extended care of young

Last, homologies not related to arboreal living
DNA sequence similarity (approximately 98%)
Chromosome banding similarity
Evidence for chimp chromosome #s 12 and 13 fusing to form human chromosome #2

More later,

Mr. Baker

Sunday, April 26, 2009

Hey there,

You may already have heard of this story, but it's a great example of biology, medicine, public health, and public policy coming together to attack a problem that faces a large population. In this case there is an apparent outbreak of flu in Mexico with isolated clusters of cases in the United States. It's a developing story. If you worked for the CDC, how would you manage this problem?

http://www.nytimes.com/2009/04/27/world/27flu.html

--Ken

Friday, April 24, 2009

The Link to the Web Lecture on Animals

Bios,

Here is the link to the Animal Diversity web lecture.

http://www.wiziq.com/tutorial/96-An-Introduction-to-Animal-Diversity

On Monday we will be reviewing the last FRQs. Please bring questions and comments to class. It will help our discussion.

Mr. Baker

Thursday, April 2, 2009

The Shop is Open

Bios,

You have a test over chapters 22-25 tomorrow and I will be available all day for questions. Just write your question(s) as a comment to this post.

Mr. Baker

Wednesday, March 11, 2009

TQT Time

Bios,

Submit your TQTs based on the chapters 19 and 21 notes as comments to this post.

Mr. Baker

Monday, March 9, 2009

Notes for Chapters 19 and 21

Bios,

Here are the notes I promised you in class. Sorry about the formatting but Blogger's text editing is a bit clunky. It may be best to copy and paste the text into a word document so you can edit the formatting. Have your book in hand as you read through the notes. I want your TQT for this week to come from this material. I will write a post for your TQT on Wednesday and please write your TQT as a comment to that post.

Mr. Baker

Chapter 19 – Cancer

1. Proto-oncogene – normally codes for a cell growth or division regulating protein. If it mutates, it may result in a change in the control of cell growth an division and cause the cell to rapidly divide and become a tumor.
2. The mutated proto-oncogene is now an oncogene.
3. There are three means to cause a proto-oncogene to become an oncogene.
a. Translocation to a new chromosomal region and promoter
b. Gene duplication
c. Point mutation of the DNA code
4. Another family of genes that are implicated in cancer is the tumor-suppressor genes. These genes have many functions such as DNA repair, cause cell death, and contact inhibition.
5. See your text for the function of the ras and p53 genes.
6. See your text (pp 359-361) for an explanation of how multiple mutations are implicated in tumor development and specific examples.

Chapter 21 – The Genetic Basis of Development

1. Embryonic development involves
a. Cell division
b. Differentiation
c. Morphogenesis
2. Model organisms
3. Differential Gene Expression
a. All cells have the same genes. The cells of a zygote are totipotent. They have not differentiated and can become any part of an organism.
i. Carrot cloning
ii. Frog embryo – from early cells, normal tadpole. From intestinal cells, only 2%. Conclusion, nuclei change as cells differentiate.
iii. Sheep clone accomplished with transplantation of the nucleus of an udder cell into a de-nucleated egg cell.
1. cultured udder cell in nutrient poor medium
2. cell went into G0 phase
3. then inserted into egg cell
4. one of several hundred survived and became Dolly
b. As a cell differentiates it expresses specific proteins.
i. These proteins regulate development and function
ii. In muscle cells it is due to a regulatory protein myoD that is is a transcription factor.
c. How does it start?
i. Maternal signals from the egg such as mRNA. These are called cytoplasmic determinants.
ii. Induced by signals from other cells
4. There is a pattern to Development
a. The pattern formation is the result of positional information given through molecular signals that tell a cell where it is relative to the body axes.
b. As your book states on page 397. “In Drosophila, cytoplasmic determinants that are present in the unfertilized egg provide positional information for the placement of the two axes even before fertilization. After fertilization, positional information operating on a finer and finer scale establishes a specific number of correctly oriented segments and finally triggers the formation of each segment’s characteristic structures.” These “cytoplasmic determinants” are mRNA that were produced by the egg during its development.
c. Read the section – “Gradients of maternal molecules in the early embryo control axis formation” on page 399 to understand how the concentration of the bicoid gene mRNA at the end of an egg determines where the body segments go.
d. Homeotic genes direct the identity of body parts.
i. The development and placement of body parts requires the identification of body regions. The genes that regulate this are the homeotic genes.
ii. For example, in Drosophila homeotic genes of the thorax direct the production of proteins that cause leg development.
e. The Hox (homeobox) genes.
i. All homeotic genes have an identical sequence 180 nucleotides long called the homeobox. Genes with this region are therefore called Hox genes.
ii. Most homeobox genes are associated with development and Hox genes are found in other animals.

Sunday, March 8, 2009

Moving On

Bios,

Now that we have finished our study of genetics we will now take on evolution. Theodosius Dobzhansky who made many important contributions to our understanding of evolutionary genetics said, "Nothing in biology makes sense except in the light of evolution." Evolution is the idea that unifies biology and maybe makes it a science rather than stamp collecting.

But now that I have piqued your interest I must temper it a bit. While you should begin to read chapter 22 on, we will finish the Drosophila experiment first. On Monday you will be introduced to the chi-square test and Tuesday you will be given time to write up your report. By Wednesday we will begin our study of evolution in class.

Also, there will be a twist to your TQT. I will be posting notes from chapter 21 and from those notes you will base this week's TQT. While reading the notes be sure to consult your text. You will find that the notes follow the text.

Mr. Baker