Features of Life
What is Biology?
Biology can be described as an explanation for the functions of the building blocks for all things living. Something that is Living for example is a plant, it has a function. It has a will to survive. Read the following to understand the characteristics of living things.
*Examples of what all living things have in common*
- Metabolism- All living organisms take in energy and matter in order to survive (ex. food). This is a way to ensure survival and reproduction.
- Inheritance and reproduction- All living organisms can produce and inherit biological information from their own parents.
- Evolution- All organisms are related but through evolution they grow, mature and adapt to the evolving changes of the world. All Asexual and Sexual offspring are able to evolve throughout generations when the alleles are passed down through DNA. Thus allowing future generations a higher chance of survival.
- Diversity- All living things have evolved into their own unique forms due to evolution. It is through these continuing changes of diversity that one can confirm the evolutionary past.
Something that is Non-Living for example is a rock, it does not require anything listed above to exist. Non-living things have no characteristics of living things.
- What determines if a particular element is reactive- Whether or not a particular reaction occurs is if their is energy available. Example, oxygen is a highly reactive element, this is because it has an abundance of energy.
- Macromolecules- Living cells and organisms are comprised of mostly water and carbon-based macromolecules (large molecules made up of many atoms). The most common of these are nucleic acids, proteins, carbohydrates, and lipids.
- How organisms function- They are cells that are made up of other nucleotide that are also made up of smaller parts called atoms.
- Energy- The sun is the main source of energy, for example plants are able to capture the energy from the suns light which they then are able to grow and produce food. When the food is eaten it then gives energy to the person or animal who ate it.
- Chemical reactions- Two broad categories take place in cells and organisms, molecules are taken apart to make smaller components or molecules are joined together to make bigger structures.
- DNA- is one type of nucleic acid located in the cell nucleus, it is the physical material of which the genes are made.
- Allele- Different versions of the same gene.
- Natural Selection- a term that Darwin used to describe how species can change overtime, and how the conditions in the natural world play a role in which animals will live to survive and reproduce.
What is an Atom?
The Living Cell
How do Organisms Reproduce?
What is an Atom?
- Atoms are tiny building blocks for all living and physical things. There is one type of atom for every element. They are the smallest unit of all living things.
- Inside the nucleus- Protons give a positive charge, while Neutrons give a negative charge.
- Outside the nucleus- Electrons give a Negative charge.
- When atoms share electrons they form chemical bonds which determines their reactivity.
The Living Cell
- The most common element that living thing are made of are cells. They are also the most basic unit of life.
- The cell theory is the realization that all things living are composed of cells. This was first proposed in 1839 by Matthias Schlseiden and Theodor Schwann.
- This short video will help you visualize and understand the full function of living cell.
- Gametes are sex cells, all organisms that go under sexual reproduction make these cells.
- Meiosis entails two rounds of cell division is begins with 2 diploid cells and ends with 4 haploid cells each with just one set of chromosomes.
- Mitosis is a second set of cell division where all the chromosomes in the cell are copied or replicated. Each new cell is then given genetic information identical to the parent cell. Mitosis and Meiosis are easily misidentified here is a short clip on the steps in each and their similarities and differences. https://www.youtube.com/watch?v=Ba9LXKH2ztU
- How many chromosomes each human has- Each human body contains 46 chromosomes organized into two sets of 23.
- Diploid Cell- A cell with two complete sets of chromosomes.
- Haploid Cell- A cell with just one set of chromosomes.
How do Organisms Reproduce?
- Sexual reproduction allows the organism to inherit DNA traits from each parent. Mother having the egg and the father having sperm. Each parent holds only half the key in making a new offspring. Separated they are both useless but together allows the exchange of information resulting in a new combination of alleles. This allows the offspring to be similar to their parents but also they are their own individual. Example adult humans have infant offspring.
- Asexual reproduction only involves one parent and no exchange of DNA with other organisms. Thus giving their offspring a complete copy of their own DNA. Example daisy's can have identical flower offspring.
- First Step is Observation and Facts- What you can see, hear, smell, taste or physically feel. Also facts you know to be true before hand.
- Second Step is your Hypotheses- This is the possible cause or reasoning behind your belief that could possibly explain your observations. Which then leads you to your Predictions, an educated speculations of what your outcome will be.
- Third Step is Testing your Hypothesis- Test your hypothesis by designing a procedure to set up the conditions your predictions require. The results of your test is your datum. The hypothesis must be able to be tested and falsified. The dependent variable is able to be measure counted or observed while the independent variable is able to be manipulated by the investigator. Controlled variables are not related to the hypothesis being tested but can change the results at the end of the experiment. Controls are used for comparison when your already know the results of that specific version prior to testing your experiment.
- Fourth Step is the Evaluation and Interpretation of the Results- The final step is to evaluate and interpret the test results.
- (Always remember to repeat the steps to confirm your findings. If your findings are not what you had originally predicted there may have been a mistake made in the previous steps. Also that even using the scientific process nothing can be proven, it can only be supported or rejected).
-An example of how we used the scientific process in lab was when we attempted to build the tallest towers. With having no rules as time progressed we began to change our building strategies overtime due to trial and error. By repeating the steps after every failure we did eventually build a tower with all the materials that were given during the challenge.
-A second example was how a doctor not only found through multiple experiments what was killing his patients but how to prevent it from happening again. He was successful with his finding after many trial and errors by using the scientific process.
-When using controlled variables for the termite experiment I learned each termite produced different results, example they each might have favored different colored pens or types of paths written with the pens over others. I also learned how to accurately collect and compare the data that I received by testing the termite in a non bias circle chart where the termite had to choose a path to follow. After the data was collected we averaged it out and make a bar graph to display the results.
-When making our own experiment in class we swabbed the inside and outsides of the mens restroom door. This experiment helped us learn how to test an area using the sterile swab and agar plate. How to collect the data and then turn the results into findings for out scientific paper.
-There is specific information a scientific paper has to have within it to be written correctly for example, Title, Authors, Abstract, Introduction, Materials and Methods, Results, Discussion, and lastly References.
- Title-Specific information that tells the reader exactly what their about to read.
- Authors- Anyone who helped with the research.
- Abstract- A summary of the paper within the paper.
- Introduction- An explanation as to what made your experiment interesting.
- Materials and Methods-Needs to be enough information given along with the exact steps in order for another scientist to be able to follow it and retrieve the same results.
- Results-Only describe results found, nothing more.
- Discussion- Do not repeat anything already written. Answer questions such as "Was your hypothesis supported? Are the results consistent with others? What other research do you want to continue?"
- References- Works Cited
It's all about the Facts
- The Assumptions of Science - The first assumption is that the rules of cause and effect hold for all natural phenomenon. The second assumption is that events are consistent and repeatable (if the conditions are the same the results will be the same also). The third assumption is that the effects in the natural world all have natural causes rather than supernatural ones, also known as materialism.
- Theories -Ideas supported by evidence (bigger than a hypothesis) of how aspects of nature work and the possibility of several scientific fields weaving together to support one another.
- Testability- A procedure for determining the evidence to support the hypothesis.
- Falsifiable- The ability to be proven wrong.
- Generality- How the scientific investigation can be applied to other situations other than the specific one scientist tested for.
- Empirical Evidence- The information one gets after a direct observation from experience, or from the results of experiments and other tests preformed during the hypothesis.
- Pseudoscience- Fake science. Can cause reputation to be tarnished, kicked out of science community.
- Quackery- Promoting the use or purchase of products or remedies even though there is no scientific proof or plausible reason for it to actually work.
- What happens during Fertilization- The sperm cell from the father fuses with an egg cell from the mother to form a one-celled embryo called a zygote. The embryo then develops into a cellular mass known as the blastocyst, with layers of inner and outer cells. The blastocyst becomes a gastrula as cells and tissues move to a new locates where they grow into organs. The embryo then develops into a fetus and eventually into a fully formed individual. Watch this short clip to visualize these steps. https://www.youtube.com/watch?v=_5OvgQW6FG4
- The Key events in Pregnancy and when they occur
- The first event is the Embryonic Development which is from conception to eight weeks. During this the embryo begins to develop the beginning of the central nervous system, the heart, limbs, nose, eyes, and ears in week 5. By weeks 6 and 7 fingers and toes are evident, and the embryo has began to make a skeleton made of cartilage. At week 8 the embryo is about 1.5 inches long, bone is beginning to replace the cartilage and all organs are developing.
- The second event is the Fetal Development which occurs from three to nine months. At month 3 the gender can be discerned and fingernails are formed. At month 4 the fetus is approximately 6 inches long and weighs 6 ounces; the skeleton is visible during and ultrasound and eyelashes, eyebrows, and hair are present. At month 5 when a stethoscope is places into a mothers abdomen the fetal heartbeat can be detected and the mother can feel fetal movement. At month 6 and 7 the organ system continues to mature and the eyes open. At month 8 and 9 the fetus increases in size, lungs mature, and body hair disappears; a typical newborn weighs around 7 pounds and is 20 inches in length. Watch this short clip to visualize these events. https://www.youtube.com/watch?v=m6aFU4Jb_0I
- Lazzaro Spallanzani Experiment- Spallanzani placed trousers on male frogs and allowed them to try and mate with female frogs, no offspring was ever developed. Spallanzani then noticed drops of semen on the frogs pants, he then combined the drops of semen with the frog eggs and fertilization took place.
- Gastrulation- a stage in the embryonic development in which cell and tissues move to new locations so they can grow into functioning organs. For example the cells that make the skin may rise to skin level while the cells that make the heart move into the interior. During gastrulation the three major types of embryonic cells that emerge are ectoderm, measured, and endoderm.
- Differentiation- the change in cells that once had unlimited potential to be changed into a cell that is now specialized. Differentiation can be used for stem cell research by using the cells to help heal or replace tissue that has been damaged by some sort of trauma to the body, example heart attack. If differentiation did not exist then there would most likely be no chance for survival.
- Gene Expression- the process where the information that a gene in encoded with is put to use.
- Negative Impacts on Fetal Development- Drugs and alcohol use are two of the most damaging and avoidable things a mother can do that will severely impact the health of their child. Examples of the aftermath of these affects are Fetal Alcohol Spectrum Disorder or FASD (encompasses a range of health issues that children will experience if exposed to alcohol during pregnancy). Also Fetal Alcohol Syndrome ( the most severe of FASD; symptoms may include poor growth, abnormal facial features, hyperactivity, poor reasoning skills, vision and hearing problems, and intellectual disabilities).
- Labor and Delivery- They are divided into three separate stages.
Stage 1- The uterine contractions pull the lower part of the uterus up toward the fetus's head and push the fetus down.
Stage 2- Strong contractions occur every minute, the mother feels the urge to push and the baby emerges (crowning of the head first, then the baby's body is rotated in order the get the shoulders out followed by the rest of the body).
Stage 3- The placenta is delivered.
- Identical Twins- They are made from a single fertilized egg that splits into two embryos sometimes during the early development. About a third of twins that are born are identical. There are three types of categories for identical twins. In the first category about 33% of the embryos have completely separate chorions (a component that forms in the placenta). In the second category about 66% of the embryos share a chorion but have separate amnions (the fluid sac that surrounds and cushions the embryo). Lastly the third category in only 1% of the embryos do they both share a common chorion and a common amnion.
- Fraternal Twins- In contrast to identical twins the mothers of fraternal twins actually released two eggs that both get fertilized by a separate sperm, resulting in children that are genetically siblings but not identical.
- Conjoined Twins- This happens about 1 out of every 50,000 pregnancies. It is so rare due to the fact that most the time the mothers body will have a miscarriage if the body detects an abnormality in the embryo. If born alive the chance of survival is less than 25% for most, more severe cases is less than 5%. about 75% of conjoined twins are connected through the chest, abdomen, or both. The true causing of conjoined twins are unknown but a possibility is the fusion of the embryos.