What are cardinal directions and a compass rose?

Let’s learn about cardinal directions.

The Cardinal Directions help us navigate from one place to another.

Time for a road trip. Your directions say the following.

Start at the center of the 48 states nearLebanon Kansas.

Then drive north until you reach the next border.

Then turn and go west until you reach another border.

Then south to the middle of the next state. Where do you end up?

In order to navigate these directions you need to know your cardinal directions.The cardinal directions are found on maps and compasses and can be found on a compass rose.

Here is one example of a compass rose.

What are the different directions found on a compass rose?

An easy way to remember this is to use Never Eat Soggy Waffles.

If you go in a clock wise manner you get North East South West.

Finally, you can add directions in between the four main directions.

Between north and east you can add northeast, between east and south you add south east,

between south and west add southwest, and final between west and north add northwest.

These are intermediate measurements.

Orbit of the Earth

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What is a chromosome?

Humans have 46, a fly has 8 and an elephant has 56

What am I talking about? Chromosomes

Inside the nucleus of eukaryotic cells is a strand of DNA . DNA is the genetic blueprint and directions for making proteins.The proteins are responsible for traits, such as hair color, height, or eye color. The DNA on chromosomes is arranged in segments called genes which are the instructions for the proteins that create the traits. This strand of DNA is a very long molecule. In fact if you were to stretch it out it would be about five feet in length. During the prophase portion of mitosis this strand of DNA begins to condense and becomes visible.

The DNA begins to coil around histone proteins.

The DNA twists and coils itself and creates a chromosome which looks kind of like an X.

Let's take a look at the chromosome in a little bit more detail. If you'll notice it has two sides that are by and large identical; these are called sister chromatid and they are held together by a centromere.

A sister chromatid refers to the identical copies formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. A full set of sister chromatids is created during interphase, when all the chromosomes in a cell are replicated. The two sister chromatids are separated from each other into two different cells during mitosis. During  mitosis, the sister chromatids separate into  daughter cells, but are now referred to as chromosomes.

Sometimes you see chromosomes represented as a karyotype.

During the cell cycle of humans the sister chromatids cross over during meiosis and create homologous chromosomes which  are two chromosomes in which one is from the male and the others from the female. They have the same genes in the same order but they have different alleles. An allele is a different form of the same trait.

A karyotype is a picture of these homologous chromosomes.  Humans have 23 pairs of these homologous chromosomes for 46 total chromosomes other organisms have different numbers and combinations.

Genetics Explained in 3 minutes

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Energy flow in an ecosystem (Updated)

All living things need energy.

Some living factors also called biotic factors get their energy from the sun. Others get their energy by eating other biotic factors and some living things like decomposers break down once living things and recycle nutrients.

 As a result, energy is always flowing in an ecosystem.

This flow of energy can be represented with food chains and food webs.

For most ecosystems, the ultimate energy source is the sun

However there are some organisms that get their energy  from reactions involving inorganic chemicals, and typically in the absence of sunlight.This is called chemosynthesis

Producers which use photosynthesis  or chemosynthesis to create their energy are a major source of energy in an ecosystem. All Plants are examples of producers.

Consumers like the krill eat the producers, carbon bonds are broken and energy is released and this energy is transferred from one trophic level to another.Cod eat the krill and their energy is passed to the cod. The seal eats the cod and the orca eats the seal.

As you move from one trophic level to another you lose approximatly  90 percent of the energy.

This is known as the 10 percent rule.

For example, if you start with 10100 kcal and move up trophic levels, by the time you get to the hawk only 1 kilocal is transferred to the hawk.

Where does this energy go?

Most of the energy is lost as heat.

The energy flow in an ecosystem follows the laws of thermodynamic.

The first law states that states that energy cannot be created or destroyed in an isolated system however it can be converted from one form to another.

The second law states that this energy conversion is never completely efficient.

As a result, most energy is lost as heat.

What is an Ecosystem?

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Characteristics of Crustaceans

Characteristics of Crustaceans

 

Humans have 206 bones in their body. The average cat has 244 bones in its body. Snakes, the most bony animals, have around 1800 bones! Can you guess how many bones a lobster has?

 

A lobster belongs to the phylum Arthropoda and the Subphylum crustacea. Arthropods are the most abundant category of animals on earth. It is estimated that between 75-84% of all animals on earth belong to this category. Examples of crustacea  include: lobsters, crabs, shrimp, and krill

What are some traits of crustaceans?

• First crustacea are arthropods.

 

• All arthropods have several traits in common. Let’s take a look at these common traits.

 

• Exoskeleton: Remember the question from the beginning? The answer to “How many bones does a lobster have?” is none! Arthropods do not protect their organs with a skeleton made of bones. Instead, they have a hard outer covering called an exoskeleton. An exoskeleton is made of chitin, a complex sugar that binds to proteins. The exoskeleton protects the arthropod and allows it to sense its surroundings, supports the organism, and is even involved in excretion. When the arthropod grows, it must periodically shed the old exoskeleton and grow a new exoskeleton in a process called molting. 

 

• Bilateral symmetry: All arthropods have bilateral symmetry. This means that if a line was drawn straight down the middle of their bodies, both sides would be identical to one another. Humans also have bilateral symmetry. 

 

• Bodies with Regions: If you take a look at a spider or an insect, you will notice that their body is made up of more than one segment. A spider has two segments, and an insect has three: a head, a thorax, and an abdomen.

 

• Segmented appendages: What is an appendage? An appendage is a portion of an arthropod that sticks out from its body and has a function. Examples of appendages include legs, arms, and antennae.

 

• The appendages of arthropods are made of many joints. A joint is the location where two parts meet. Humans also have joints where our bones come together.

Most crustaceans live in water, but some live on land. 

 

In addition crustacea,

 

• The head has two compound eyes,

 

•  Two pairs of antennae,

 

•  Three pairs of mouthparts

 

• The abdominal segments have at least five or more swimmerets (swimming legs)

 

 Common examples of Crustaceans include, 

 

Crabs,

 

Lobsters.

 

Prawn

 

Copepod

 

Crayfish

 

Fiddler crab

 

Krill

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Types of Solutions-Isotonic-Hypertonic-Hypotonic-Animation

Matter can be classified as either a pure substance or a mixture.

So let’s take a look at the difference between the two.

A pure substance is either an element or a compound. All of the elements found on the periodic table are pure substances. They cannot be chemically separated. 

Compounds which are elements bonded together are also pure substances.

For example, water contains two hydrogen elements bonded to one oxygen.

Carbon dioxide is two oxygens bonded to carbon. They require a chemical process to separate the compound.There are millions of compounds found in the world.

Mixtures on the other hands are a combination of substances that can be separated physically.

There are two kinds of mixture, homogeneous mixtures and heterogeneous mixtures. 

A mixture that is uniform, or the same throughout is a homogeneous mixture. You often hear them referred to as solutions.

Some common examples include,

• Gatorade
• Gasoline,
• Alloys like brass which is a mixture of copper and zinc

A heterogeneous mixture is one that is not uniform and is different throughout.

Examples include a

• Fruit salad
• Oil and vinegar
• Soil

Here is a simple flow chart to help you classify something as a pure substance or a mixture

Can it be separated physically ?    No it's a pure substance 

Can it be separated by a chemical process? no it is an element  yes it is a compound

Can it be separated physically?  yes it is a mixture

Is it uniform throughout? yes it is a homogeneous mixture  no it is a heterogeneous solution.

Rates of Reaction

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Autotrophs and Heterotrophs

When you eat a slice of pizza you are transferring energy from the sun. This may surprise you but the sun is the original source of energy for your body.So let’s take a look at the difference between an autotroph that gets energy directly from the sun and a heterotroph that gets energy indirectly from the sun from other sources, like a pizza.

All  plants and  other organisms that produce their own food in an ecosystem are called autotrophs or self feeders.

An autotroph is an organism that collects energy from sunlight or inorganic substances to produce food.

The most common autotrophs are plants. Plants take sunlight along with water and carbon dioxide to produce glucose in a process called photosynthesis.The glucose is then used as energy. Bacteria and some protists also use photosynthesis to produce glucose which is then used to produce energy.

Where there is no sunlight some organisms like giant tube worms use bacteria found inside them  and then oxidize hydrogen sulfide, add carbon dioxide and oxygen, to produce sugar, sulfur, and water.

Autotrophs are also called producers.

Autotrophs are the foundation of all ecosystems. 

A heterotroph is an organism that gets its energy requirement by consuming other organisms.

They are also called consumers.

A heterotroph that eats only plants is called a herbivore.

Heterotrophs that eat other heterotrophs are called carnivores. Examples would include lions and wolves.

An organism that eats plants and animals are omnivores. 

Examples includes bears and humans.

Decomposers like bacteria and fungi are also classified as heterotrophs. They play a very important role in an ecosystem because they recycle nutrients back into the ecosystem.

Two types of decomposers are detritivores which eat fragments of dead matter. Examples include worms, dung flies, sea cucumbers, and sea stars. 

Saprotrophs are organisms that feed by absorbing dead organic matter. Most saprotrophs are bacteria and fungi. 

Anytime you see something rotting like this log you know a saprotroph is hard at work.

Plant Kingdom

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Find the Lowest Common Denominator - Step by Step Directions

How to find the LCD

When you add fractions the denominators of the fractions need to be equal.

For example, when you add 1/4 plus 1/2 you need to find a lowest common denominator.

Follow these steps to find the least common denominator.

Step 1. Create a factor tree for each denominator.

Step 2. Write the prime factors in a chart. ( You can see an example in the video)

Step 3. Multiply the prime numbers in the chart but if you have pairs of the prime numbers then only multiply one number.

Step 4. The sum of multiplying the numbers together is the LCD.

Step 5. Divide the LCD by the denominator and multiply the numerator by this answer. 

Example Problem

1/4 + 1/2

The LCD is 4

4/4 = 1 and 1 x 4 = 1 so you get 1/4

4 divided by 2 = 2

1 x 2 = 2 so you get 2/4

1/4 + 2/4 = 3/4

Find the LCM

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