Seafloor Spreading

Above: The Worlds Seafloor

Seafloor spreading (This is how the Mariana's Trench was formed)

Post the map and description of the following:

What is sea floor spreading?

occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics

What are some of the major land forms that are created from plate movement?

The seperation of land (ex. Pangaea into the 7 continents), trenches, mountains, canyons, and more.

How were the Mariana Islands formed?

constant vocanoe activities where the eruption cooled. Thosands of years in-the-making!

What evidence exists today that the plates are still moving and that the islands are ancient volcanoes?

Earthquakes and vocanoes, as well as the samples collected on atolls.

What is an atoll?

An atoll is an island of coral that encircles a lagoon partially or completely (sinking island)

Why are atolls mainly found on the Pacific?

Because of the ring of fire (many vocanoes in one area, gives a bigger chance of atolls), and most importantly, is because coral reefs grow survive on atolls, and in order to do so, they need warm water.

Pillow Star

Pillow Sea Star

Classification Kindom: Echinoderms
Phylum: Echinodermata
Class: Asteroidea (seastars)
Habitat: Shallow patch, barrier, and fringing reefs.
Food Source: may consume coral polyps, clams, and oysters; or any animal too slow to evade the attack (e.g. dying fish) or algae.
Description of life cycle: As same as a Starfish
How does it move: cannot move quickly. However, like starfish from genus Astropecten and Luidia are capable of rapid, creeping motion: "gliding" across the ocean floor. This motion results from their pointed tube feet adapted specially for excavating patches of sand.
Unique characteristics: Pillow seastar can right itself if rolled over by inflating half of its body until the tube feet can get a grip. As it grows, it loses its arms and becomes spherical. Starfish are capable of both sexual and asexual reproduction

Role in the ecosystem: These bottom dwellers play a crucial role in the ocean ecosystem, as prey when they are free-floating larvae and as predator when they reach adulthood. Few animals eat adult Pillow Stars, which are apparently neither palatable nor nutritious.

Genetics-Cell Cycle Questions

1. What is DNA?

• DNA or Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of DNA molecules is the long-term storage of information and is often compared to a set of blueprints, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules.

2. What are the 4 bases?

• Guanine
• Cytosine
• Adenine
• Thymine

3. What 2 pieces of information did the scientists need to solve the elusive structure of DNA?

• base-pair interactions
• Genetic engineering

4. What are the specific base pairs?

• Adenine (A) forms a base pair with thymine (T), as does guanine (G) with cytosine (C) in DNA. In RNA, thymine is replaced by uracil (U).

5. How does the pairing rule effect the shape and structure of DNA?

• The sequence of the pairings forms a code which holds genetic information. When the code is paired, each rung in the helix would become equal in length, and the sugar-phosphate backbone will smoothen.

6. What does the DNA do during cell division?

• Cells stop dividing because the telomeres (protective bits of DNA on the end of a chromosome) become shorter with each division and eventually can no longer protect the chromosome.

7. How many base pairs does E. Coli have? How long does it take to replicate? How is the DNA packaged in the cell?

• E. Coli has around 4 or more million base pairs. They can replicate in millions in minutes and billions a day. E. Coli is package tightly to a cell in condensed fashion.

8. How many base pairs does Human DNA have? How long does it take to replicate? How is the DNA packaged in the cell?

• About 3 billion pairs in about a half to a full day. It is packaged in 23 distinct chromosome pairs that’s “Spiral” shaped.

1. What is RNA? How different is it from DNA?

• Ribonucleic acid is a nucleic acid, consisting of many nucleotides that form a polymer. In RNA, each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate

2. How are the RNA messages formed?

• Messenger RNA (mRNA) is single-stranded. Its sequence of nucleotides is called "sense" because it results in a gene product (protein). Normally, its unpaired nucleotides are "read" by transfer RNA anticodons as the ribosome proceeds to translate the message.

3. How are the RNA messages interpreted?

• Codons, in groups of three nucleotides.

1. Describe cell cycle.

• Cell’s chromosomes are divided between the two daughter cells, and cytokinesis, in which the cell's cytoplasm divides forming distinct cells. From here, the cells continue to divide by two in a repeated process.

2. What is nuclear division.

• When the nucleus divides and engage with subphases

3. What is interphase.

• Interphase is a phase of the cell cycle when the cells obtain nutrients.

4. Cytokinesis.

• is the process when the cytoplasm of a single cell is divided to spawn two daughter cells

5. Homologous chromosomes.

• Are chromosomes in a biological cell that pair synapse during meiosis, or non-identical chromosomes that contain information for the same biological features and contain the same genes at the same loci but maybe different genetic information.

6. Phases of mitosis (5 of them).

• Interphase, Metaphase, Anaphase, Telophase, Cytokinesis

7. Phases of meiosis and how it is different from mitosis.

• Prophase I , Metaphase I, Anaphase I, Telophase I, Prophase II , Metaphase II, Anaphase II, and Telophase II. Meiosis may start out the same as with mitosis, but then they eventually split once again after the first cytokinesis to form more chromosome 8.

8. Describe the process and purpose of crossing over.

• Crossing over is a process when two chromosomes are paired up during prophase 1 of meiosis, and then the exchange of some portion of their DNA. Crossing over is mainly initiated in pachytene, before the synaptonemal complex develops, and is not completed until near the end of prophase 1. Crossover usually occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome. The result of this process is an exchange of genes, called genetic recombination.