Biology Review. Chapters 1 through 5. The Study of Life. The concepts and principles that allow people to understand the natural environment form the core of Biology, which is basically the study of life.
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The concepts and principles that allow people to understand the natural environment form the core of Biology, which is basically the study of life.
One of the most basic aspects of Biology is that living things do not live in isolation. There is a direct link in all living things that help support the entire planet. These things supply life to other organisms, medicine, symbiotic relationships, etc.
How does the study of life have relevance to people? Does study of life need to include the study of non living things? If so, how?
There is order in the natural world. God has designed living things to interact with each other to from a natural environment that supports itself and His creation as well as providing a way for life to thrive on Earth. Since the beginning, God has expected man to be good Stewarts of the Earth. Biologists term this relationship as the web of life.
Please indicate how human beings fit into this web and some of our responsibilities in maintaining a healthy web, along with this list the benefits of studying Biology.
Energy is the ability to cause change and all organisms get their energy from food.
Distinguishing between a living thing and a non-living thing can be tricky at times. There are non-living things that seem to have “life” but do not fit the description, or parameters of living things. In order to be considered an organism, the thing must have all of the following characteristics.
Consider the mildew that can be found on the rotten fruit we used to attract the fruit flies. Examine the structure under a microscope (teacher will set up). Note: If you have allergies of any type have a fellow student describe to you what they are seeing. Do not touch the slide.
Write an hypothesis about rather this is living or non-living. Examine the slide again in a couple of days and write what changes you have seen. Turn in with revised hypothesis, data, and what you inferred. Research if you were correct and submit a paper with results including the references.
Some of the abiotic factors that make up an environment are air, water, weather, temperature. Organisms (living things) within an area, have the capability of responding to the environment and the abiotic factors present in that environment. These organisms respond to their environment in many ways. A tree may change it’s color and shape in weather. A fox may pounce on a rabbit when hungry. In turn, a rabbit may run for cover when it rains. Any response to a stimulus is normal and to be expected in the natural world. The internal responses are adaptations that God has placed in the organism.
All living things have a quality they possess that can respond to internal and external stimulus in order to survive and be able to reproduce. This adjustment is known as homeostasis, and is the process of internal feedback. In order to reproduce and live, organisms use energy which causes change.
The inherited structure, behaviors, and internal processes are able to respond to environmental factors. These responses are known as adaptations.
Give an example of a species, and a stimulus that would cause the species to adjust and respond to the stimulus (adaptation). Remember the rolly polly?
The gathering of information and attempts to systematically answer questions is known as scientific methods.
Consider science as being an investigator, not unlike a detective you see on television. An investigator can see a problem, or have a question. He or she will then set out in a systematic way to answer those questions and find the correct answer. The following slides will explain the process of being a scientific investigator and then you will investigate a question.
Hypothesis. Is an explanation for a question or a problem that can be formally tested. In order to form a hypothesis the investigator (scientist) must be able to test it. A hypothesis is NOT a guess. The investigator must be able to consider a question, use previous knowledge, data, or research to form a reasonable thought as to the answer of the question. He or she must also be willing to accept that the hypothesis may not be correct and may need to adjust the answer or answers. Otherwise there is a built in bias (or tendency to follow down a wrong path to come up with a preconceived idea). The investigator must be sure that he or she does not allow for a bias to influence the testing, results, or interpretation of data. In short, keep an open mind young minds.
An experiment is the process of testing a hypothesis by collecting data, or information, under controlled conditions.
TO-DO: Divide into your learning groups with all of your technological gadgets. Consider the fruit fly. Give an example of a hypothesis that was incorrect. Then, give an example of a revision of the hypothesis based on RESEARCH of a fruit fly. Then, describe the experiment and describe the observations such as exponential growth, abiotic factors, etc. Use terms you have learned like dispersal, etc. Now that you know the terms and concepts you should be able to produce a nice document to display during open house.
Experiments break down into two groups. The control group and the experimental group. If you are testing something like a plant, the control is the conditions similar to all plants, like they would all have soil, same water, etc. The experimental group would be a set of plants that had fertilizer (but not all plants would have fertilizer). Then, you would collect data by quantitative (measurements) and qualitative (observations), and make inferences from that data which supports (either confirms, rejects, or is inconclusive to your hypothesis).
The designing of an experiment is only limited to the depth of your imagination and creativity. Also, researching other experiments and consulting with others can help you design a unique and challenging experiment.
In a controlled experiment, only one condition can be changed at a time, because you must be able to determine which factor is influencing any changes you are seeing. If you try to test a hypothesis with more then one condition (in the experimental group) then you will not be able to determine which condition causes the data, or changes that you may observe.
The condition in an experiment that is tested is the independent variable (this condition takes place in the experimental group). In other words, it’s the item that is not consistent with both groups. There is also the chance that there will be no difference in the experimental group as opposed to the controlled group. This would result in an inference that independent variable being tested is having no affect on the group. Either way you have data and can make an inference.
Say you are testing a group of plants and you have a change that is observed or measured in the experimental group. This change, or condition would be known as the dependent variable.
Think of the fruit flies and come up with a set of variables that are the same for all, then add a variable that is different from the other 2 “communities”. Explain what the independent variable would be and what the dependent variable would be.
In some experiments it may be impossible to apply controls without affecting the natural environment. Under these circumstances the person conducting the experiment would need to do an observational experiment which would rely on making direct observations without interfering with what is occurring in the natural settings. You see these types of studies when Biologists study species in their natural environment. An example would be the study of elephants. The Biologist would watch their behavior, make notations on what they’re seeing and then try to make some sort of inference based on what they see in the behavior and what responses they may note.
The study of plants, animals, what they eat, where they grow and live; and what they eat or what eats them is called natural history. So, the branch of Biology that developed from natural history is known as ecology.
Ecology is the study of interactions that take place between organisms and their environment. Most ecologists use descriptive and quantitative research. That is, descriptive is what they observe and quantitative is what they can measure.
When you think of the biosphere, think on a large scale like in comparison to the galaxy and beyond (Toy Story, quote from the famous Buzz Light-year.) Then, think of all the life that is supported from the bottom of the ocean to the top of our atmosphere.
Biotic Factors are all the living organisms that inhabit an environment. Remember that an environment is simply the surroundings of organisms that are in interaction with each other. For example, this classroom is considered an environment. Of course there are factors contained within an environment such as weather, temperature, other organisms, and non living factors, these are known as abiotic factors.
Abiotic factors. Do you know what abiotic means? And, do you understand the importance of abiotic factors on living organisms?
There are some important terms in studying ecology.
A population is defined as a group of organisms (all the same species) which live in the same area at the same time. Give an example of a population (non human) that lives on the school grounds.
A biological community is simply a bunch of different populations that inhabit the same general area at the same time. Give an example of a biological community that lives on the school grounds.
An Ecosystem is simply an extension of population and biological community. An ecosystem is a population, biological community, AND the community’s abiotic factors. Remember there are 2 major kinds of ecosystems; terrestrial and aquatic.
Class discussion: Are the following considered ecosystems? Forest, yard, empty lot, rotting log, pond, stream, and hill at school????
A habitat is simply the place where an organism lives out its life. It could be a stream, a field, or a rotten log, but it’s “home.” Habitats can be lost due to human neglect or natural factors such as floods, etc. So, what is the difference between a habitat and an ecosystem?
How about a niche? What is it? How do we define it? And why does it matter?
A Niche is all the strategies and adaptations that a species uses to live out it’s life. It includes all of the interactions of Abiotic factors and Biotic factors in its environment. Try to think of it as the history of a species in a particular area. Who its friends are, what its adaptations are, where it lives, how it thrives, etc.
Most species survive because of their relationship with other species. It does not always have to be that there is competition between species at all times. In fact, most of the time the role of one species helps another for their mutual existence.
When there is a relationship with a permanent and close association between species, it is known as symbiosis. Remember when we led each other around with one person with closed eyes and the other helping them to walk? That was an example to help your remember this concept. There are basically 3 types of symbiotic relationships that follow.
Mutualism. Both species benefit from their relationship. Mutual means to share so they are sharing something to both benefit. A lady bug on a rose. The lady bug eats a fungus that would kill the rose so the lady bug gets fed and the rose gets protected.
Commensalism. One species benefits and the other is neither harmed nor benefitted by the relationship. Consider moss at the base of a tree. The tree doesn’t benefit nor is it harmed by the moss, but the moss benefits from the habitat supplied by the tree. Shade, etc.
Parasitism. One species benefits and the other is harmed. Imagine if a tick gets on your head. The tick is living off of you, and is a carrier of say rocky mountain fever. You are then harmed by this illness (no bueno).
The ultimate source of energy for all life on Earth is the sun.Organisms that use light energy or energy stored in chemical compounds to make energy rich compounds is known as a Producer (Autotroph). Examples would be plants, fruits, etc.
An organism that feeds on other organisms in order to get its food (energy) is known as a consumer (heterotrophs). An example of this would be a Bison (Remember George????).
Organism that are Consumers can be broken down into 3 subcategories.
A. Herbivore-only eats plants.
B. Carnivores-eats other animals. Note: Some animals do not kill other animals, but they eat those animals which are dead or dying, these are known as scavengers.
C. Omnivore-Us humans, we eat everything! Plants and Animals.
Bacteria and fungi break down complex compounds of dead and decaying plants and animals these are called Decomposers.
Energy is said to flow through an ecosystem and never really decrease. It is looked at as converted into heat or reabsorbed and reused, etc. But, our main thought is to know the basic principal of a food chain. An example is berries being eaten by a dear, who is then eaten by a black bear. The berries are on the lowest form of this chain, the next level is the deer, and then the bear. Interestingly, anything left behind by the bear will be taken up by the Decomposers and thus starting the cycle again. These levels of the food chain are known as trophic levels.
Limiting factors are those things that affect an organism’s ability to survive in its environment, such as the availability of water, food, predators, etc.
A limiting factor is any abiotic (non living) or biotic (living) factors that influence an environment of an organism. Let’s use the mouse as an example. A lack of cover (abiotic) affects the mouse and his or her opportunity to avoid the Hawk (biotic) that would swoop down and scoop him or her up as a meal.
Range of Tolerance is the ability of an organism to withstand fluctuations in biotic and abiotic factors. A population will survive according to its tolerance for environmental extremes, and of course its tolerance for biotic factors increasing or decreasing dependant upon the type of symbiotic relationship.
The natural changes that occur over time, or species replacement is known as succession. Succession takes place over time. Some organisms may move into an area, some may die out, etc. These changes will affect the ecosystem, or that area that supports the biological community. There are 2 types of succession:
1. Primary Succession is an area where the land was barren of organisms. At some point, when conditions are proper, the first species to take hold in an area takes hold. These species are known as pioneer species and are usually the smallest of organisms. Think back to the example of a food chain and how small organisms attract bigger organisms.
2. Secondary Succession is an area that has already built up but is wiped out by an event, such as fire. The species can survive or at least have microorganisms that will survive and grow and eventually repopulate. Think of some of the burn areas that have come back. The fire represented change but not total devastation. It may look totally devastated but there is still organisms within soil, etc. that will come back.
A climax community is a community that has reached a stable point where it undergoes very little change.
A biome is a large group of ecosystems that have a bunch of grouped and stable communities within them. They are subdivided into 2 different types. Terrestrial biome (land & Air) and Aquatic biome (sea’s, lakes, ponds, etc.) Approximately 75% of the Earth is covered with water. These biomes are separated into groups such marine biomes (saltwater) and freshwater biomes. The portion of the aquatic biomes that can receive light (shallow enough for it to penetrate) is known as the photic zone which is important for life within those waters, much the same way that sun is important for life on terrestrial biomes.
A population is a group of species that all live in the same area. Our fruit flies were considered a population.
The growth of populations generally start off slowly and then grows faster as the organisms grow and the group has more organisms that can reproduce. At some point the growth begins to grow exponentially and if you were to graph to populations growth you would have a J shaped curve.
Populations do have growth limits and these limits are availability of food, predators, disease, and lack of space. When this happens the J shaped curve stabilizes as the populations approaches its carrying capacity.
Carrying capacity is the number of organisms that an environment can support indefinitely.
Remember that carrying capacity is what an environment can hold in terms of population. Remember there will be numerous species within an environment but the population is the key here. How many organisms can be sustained. Recall that in an environment too many predators, or too few predators can have an impact in terms of limiting factors and growth. But, once the population reaches a certain limit it cannot be sustained because other factors such as availability of food, disease, etc. will come into play.
When carrying capacity is reached, the population will fluctuate because of limiting factors. At times the population will exceed capacity, then die or disperse and then fall below capacity due to these issues.
Organisms disperse through an environment in 3 different ways, which are:
1. Random it just happens. It could be the wind blowing seeds in a certain way, or a fox carrying seeds in his digestion system to plant them where he relieves himself.
2. Uniform is due to room. A group of trees for example needs a certain space to grow, so they will grow but in a uniform appearance. The limitation here is tied into available space for them.
3. Clumped, is a form of dispersal of a source usually brought about by either food needs, or safety. Mushrooms will clump in the ideal growing space for them, or newborn animals will clump together for warmth and protection.
There are 2 types of limiting factors related to dispersal. They are density dependent factors and density independent factors.
Density Dependent factors are directly related to the population of an area. The heavier the population the more likely that limiting factors will affect the area in a bigger way. These limiting factors are disease and parasites will increase their effect; competition for resources like hiding spots, food, room to grow etc.
Density Independent factors can affect an area regardless of population. These are things like floods, pollution, drought, temperature, volcanic eruptions, etc. NOTE: These factors tend to be Abiotic factors.
In a balanced ecosystem there is a proper balance between predator and prey, or species that affect that environment. But, imagine if you introduced a bunch of coyotes to an area that has few rabbits. The coyotes would soon decimate that population of rabbits and that would also harm those organisms that depend on the rabbits for their survival. In a properly balanced system there is enough birth and continuance of prey to support the predator and keep things moving along in blissful harmony. But, tamper with it too much and things will certainly change for the worse. This is why hunting is carefully monitored for the good of an area.
Interestingly, overcrowding has been studied and found to be a limiting factor. Although not completely understood, studies have shown that when overcrowding exists. If we had kept the fruit flies longer we probably would have noticed this effect. However, individual animals have shown patterns of increased aggression, decrease in parental care, decrease in fertility and resistance to disease under circumstances of crowding. Does this happen in humans?
Growth rate is simply adding the births and immigration rate together and then subtracting the deaths and emigration (people leaving). This will result in either a positive growth rate, negative growth rate, or rarely no growth.
Biological Diversity (Biodiversity) refers to the variety, or different types, of species located within an area. For instance, you would have more types of species in a rain forest then you would in a corn field. The larger the number of species within an area the greater the Biodiversity. Remember the importance of symbiotic relationships amongst species, if an organism is lost, it will affect other organisms.
Extinction is the loss of a species to the last one, where they are lost forever and will never return again.
Endangered species are those that are at risk of becoming extinct. There are numerous types of sea turtles that fit this definition and need to be protected. Protection programs are designed to save these species from extinction. For instance, in Hawaii it’s against the law to touch a sea turtle while snorkeling or scuba diving.
Threatened species are those that are in danger of becoming endangered and need conservation efforts as well.
Habitat loss is one of the biggest reasons for decline in biodiversity. The Amazon rain forests, and the coral reefs are examples.
Habitat fragmentation is the separation of wilderness areas from other areas. Building of roads and other man made things cause most of the fragmentation. This causes problems due to increased risk of fire, changes in local climate, increased disruption of ecological processes, and new opportunities for invasions by introduced species, which are also known as exotic species.
An edge effect is where 2 different types of ecosystems come together. For instance, a new housing development against a forest would change that edge effect, possibly introduce new species, and possibly disrupt the species that have been displaced or that live deeper in the forest.
Habitat degradation is simply the damage to a habitat by pollution. There are three types of pollution that exist.
Air pollution is brought about by particles being put into the air by man made processes such as manufacturing, etc. Occasionally, however, abiotic factors such as large fires come into play and pollute the air. This type of pollution is much easier on the environment however because there is a natural cleansing process such as winds, rains, etc that can more readily remove fire pollutants.
Land pollution is largely brought about by garbage. We consume and then we have waste and there is an on going need to balance and be innovative in managing this type of pollution.
Water pollution is brought about when contamination is brought into any water source. It could be intentional dumping of wastes, or just the washing off of pesticides by rain into water systems. Whatever the cause, this affect can be devastating on aquatic biomes.
Some elements such as iron and copper are present in living things in very small portions. These small amounts are called trace elements. Trace elements are absorbed into plants through the root system and transferred to animals, or people. Trace elements aid in cellular metabolism, so although they are found in small quantity they are vital to cell function and life.
Rather elements are found in living or non living things, the smallest particle of the element is an atom. Atoms are the basic building blocks of all elements. Page 142
All nuclei are positively charged because of the presence of protons.
The different elements have different numbers of protons.
Electrons, which are negatively charged, circle the nucleus. There are “shells” that circle the nucleus in rings. The first cell can hold a maximum of 2 electrons, the 2nd layer can hold 8, and the 3rd can hold a maximum of 18. 143
A compound is simply 2 different elements that combine. For example, when sodium and chloride combine you have table salt. Elements combine when they are going to be more stable. This simply means that the outer shell reaches its maximum.
There are 2 ways in which atoms bond. One is they share electrons (covalent bond) and the other is to gain or lose electrons (ionic bond). Page 147
In organisms, chemical reactions occur within cells. That’s why we live and die one cell at a time. (Rapidly of course!). All of these chemical reactions are known as the organism’s metabolism. We are constantly breaking down substances, rebuilding new substances, using nutrients, getting rid of wastes, etc. Page 147
The cell theory is made up of 3 main ideas. Pg. 172
1. All organisms are composed of one or more cells.
2. The cell is the basic unit of structure and organization of organisms.
3. All cells come from preexisting cells. By duplication and forming identical cells.
All cells contain specialized structures called organelles. These break down into 2 distinct types of cells. Those that do not have membrane bound organelles called prokaryotes (example would be most bacteria). And, those cells that do have membrane bound organelles, which are known as eukaryotes. Most, but not all, eukaryotes are multicellular organisms the exception would be some algae and yeast, as well as amoebas.
Your cells need nutrients such as glucose, amino acids, and lipids to function. It is the job of the plasma membrane to allow, or not allow, these into the cell. Plasma membrane play an important role in cellular homeostasis by allowing certain nutrients in, and letting waste out. One such mechanism is selective permeability. Think of a screen in your home that lets fresh air in, and keeps big nasty mosquitoes from getting in and getting you.
Although cells have a semi permeable membrane (in most cases), water moves freely into and out of cells to reach a balance. This movement is called Osmosis. It is simply water trying to reach a balance, between what’s inside the cell and what’s outside (extracellular).
Isotonic solution the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell.
Hypotonic solution is the concentration of dissolved substances is lower in the solution outside the cell then the concentration inside the cell. Remember hypo means below, so a hypotonic solution means the solution has less dissolved particles in it then what is inside the cell.
Hypertonic is the concentration of dissolved substances outside the cell is higher then the concentration inside the cell.
When cells move across a membrane requiring no energy the movement is called passive movement.
Passive movement can occur when a particle is transported by proteins. Transport protein help substances move through the plasma membrane. The protein is attached to the cell membrane and provides a bridge of sorts for certain material to pass through and into the cell. This type of passive movement is called facilitated diffusion. These channels allow specific molecules to flow through. In facilitated diffusion by carrier protein the movement is with the concentration gradient and requires no energy input from the cell.
A cell can move from particles of a lower concentration to a region of higher concentration, but it must expend energy to counteract the force of diffusion (like swimming against a current). Movement of materials through a membrane against a concentration gradient is called active transport and requires energy from the cell.
In active transport a transport protein called a carrier protein first binds with a particle then it carries it into the cell through a portal (or door) of a cell and then releasing them. The cell uses energy to take in the particle, and energy is used in picking up, binding, and carrying the particle into the cell. There is also communication within the cell, kind of like a door man that lets the cell know it’s OK to let the particle inside.
Endocytosis is a process by which a cell surrounds and takes in material from its environment. The material does not pass directly into the cell membrane, it is engulfed and enclosed and eventually absorbed into the cell.
Exocytosis is the expulsion (or getting rid of) materials from a cell. This is how the cell expels wastes. Cells also use this method to secrete hormones. Both of these processes use energy and move masses of material.
Starting 11/29 period 1 will review 5 slides per day as homework. When class starts you will sit down in your learning groups for 20 minutes and review the slides you did the previous night as homework. You will use your electronic gadgets, but once this time period is over you will put them away and keep them OFF.
Starting 11/30 period 6 will review 5 slides per day as homework. When you come to class break up in your groups and review those slides as group study using your gadgets to enhance learning for 30 minutes. Once this is over all gadgets are OFF and put away.
NOTE: If anyone is not working on their slides as I monitor you, you will be broken up to study alone and will receive NO participation points for this exercise. Participation points will only be issue when you stay in your group, stay in your seats, stay on track, and keep the noise volume down to inside voices. This will help you prepare for the final in 2 weeks.