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Transcript of Life Science
Structure of Life
Structure and Function
Physiology and Behavior
Physiology refers to an organism's internal activities, like when a plant closes openings on the undersides of it's leaves to conserve water on a warm day. Behavior involves external activities, like when a spider spins a web to catch insects.
Genes and Heredity
Change and Diversity of Life
An ecosystem is all the organisms that live in an are together with the nonliving factors of the environment.
Tissues, Organs, and Systems
Different organisms may use different structures to do the same job. Microscopic organisms and other animals, for example, have different structures that help them move. Birds use wings, fish use fins, and some bacteria use flagella.
A cell is the basic unit of structure and function of life. Cells can reproduce themselves. New cells can only come from existing cells. Many organisms, like bacteria, are unicellular, or made up of only one cell. Earthworms, trees, mushrooms, and humans are multicellular, or made of multiple cells.
Plant cells consist of a cell wall, cell membrane, cytoplasm, nucleus, nuclear membrane, nucleolus, chloroplast, mitochondria, endoplasmic reticulum and ribosomes, golgi bodies, and vacuole.
An animal cell consist of cell membrane, cytoplasm, nucleus, nucleolus, vacuoles, mitochondria, endoplasmic reticulum and ribosomes, and lastly, golgi bodies.
Your body, like many other animals, is made up of several types of tissues. Plants contain tissue too.
An organ is a structure made up of two or more tissues that work together to carry out a specific job.
For example, muscle tissue allow your stomache to churn and grind food.
An organ system is made up of all the organs that work together to do a specific job. One example, is your digestive system.
The Human Body
In your body there are trillions of cells organized into tissues, organs, and organ systems that keep conditions inside you're body stable, no mater the conditions outside your body.
Types of Tissues
Epithelial - covers the outside of the body. ex, skin.
Connective - fills in spaces and connects other tissues together.
Muscular - contacts and relaxes to allow movement; makes up most organs.
Nervous - transmit messages through the body.
Skeletal and Muscular Systems
These two organ systems work together.
All humans have a stiff inner skeleton made of bone and a hard, but flexible tissue called cartilage. These bones have jobs.
they suppor your body and give it shape
to protect your internal organs
to allow you to move
store minerals and make blood cells
Knees, elbows, hips, and shoulders are some examples of joints. Joints are where two or more bones meet. Ligaments hold the joints together.
There are three types of muscles:
Skeletal Muscle - they contract to move bones. Voluntary.
Smooth Muscles - these are not in your conscious control. Involuntary.
Cardiac Muscle - found only in the heart. It keeps your heart beating throughout the day and night. Involuntary.
Digestive and Excretory System
These two also work together.
This is the system that breaks down your food into substances your body can use. There are two types of digestion:
Mechanical - breaks down food into smaller pieces.
Chemical - uses enzymes to break down large food mulecules into smaller molecules that can be taken in by cells.
This moves wastes produced by the activities of cells.
Respiratory and Circulatory Systems
They take in oxygen and transport it to cells.
It takes in oxygen. It also gets rid of carbon dioxide that your cells produce as waste.
Transports needed substances throughout your body and carries away wastes. Made up of your blood, heart, and blood vessels.
Nervous and Endocrine Systems
Message centers, they transmit information throughout your body in different ways
Controls and coordinates your body's activities and helps you sense and respond to changes in your environment.
Regulates body activities by producing chemical messengers in glands.
This is what protects pathogens from entering your body. White blood cells also protect you from pathogens. White blood cells can produce antibodies, which bind to pathogens and help to destroy them.
Cells from two organisms unite to form a cell that develops into a new organism. In humans, a sperm, produced by the male, must unite with an egg cell produced by the female, to form, in about 40 weeks a fully developed baby. This is called fertilization. Once fertilized the one cell formed divides to make more cells.
Once the one cell produced through fertilization divides and makes a microscopic ball of cells, known as a zygote, these cells attach to the lining of the uterus, forming an embryo, causing a placenta to form. This is responsible for the exchange of nutrients and wastes between the mother and the developing baby.
During the first eight or so weeks of pregnancy the embryo develops a beating heart, eyes, and a brain. After eight weeks, it develops more human features and it's called a fetus. By three months the fetus has developed all of it's organs and in the next weeks, until it is 40 weeks old and ready to be born, it will grow rapidly.
Is the study of all the physical and chemical processes that take place inside the body of an organism as it goes about its daily activities.
This is an activities or action that helps an organism survive in it's environment, or surroundings.
The process of making more of one's own kind.
1. Before the cell divides, each chromosome copies itself. Held together at their centers, the copies form a sort of "X."
2. Each chromosome in a cell has a homologous, or similar, pair. These pairs now line up two-by-two in the center of the cell.
3. Each side separate from each other and form two cells. Now each cell has onle one similar pair of chromosomes. Half of the oroginal one cell.
4. The chromosomes now all line up in a single line
5. The "X" shape chromosomes split in two in both cells, and then they separate.
6. Now there are four cells, each new cell only has half the number of chromosomes than the original cell has, and therefore only half the amount of genetic material.
DNA is a very large molecule with a shape similar to a twisted ladder. The rungs of the ladder are made up of molecules called bases. The bases are adenine, thymine, guanine, and cytosine. These bases always pair up so that adenine is with thymine, and guanine with cytosine. The sides of the ladder are made up of phosphate and sugar molecules.
Genes are segments of DNA that carry instructions for the traits of an organism from parent to offspring. They are located on chromosomes in the nuclei, or center of cells. A chromosome may contain thousands of genes. Genes determine all your traits. Females have two X chromosomes, males have one X and one Y. Humans have 23 pairs of chromosomes, in each cell.
Recognizing Common Ancestors
The Theory of Evolution
The passing of traits from parents to offspring in called heredity. Many easily observable traits are inhertred, including, hair and eye color, skin type, and height. traits for health conditions can also be inherited.
Dominant and Recessive Alleles
Each gene pair is known as an allele. If one of the alleles masks the effect of the other allele, it is called a dominant allele. The allele that is masked by the dominant allele is called a recessive allele.
A Punnett square is a table that can be used to prdict what traits offspring will have based on those of the parent. The top of the table shows the alleles contributed by the male. Along the side there are two alleles that the female contributes.
Animals such as tiger, lions, and jaguars are different animals but they share certain features that show they are related to each other and different animal species. Scientists have found evidence suggesting that all organisms on Earth share a common ancestor.
Earth has many organisms some big as a whale and as small as an ant. This variety of life is known as biodiversity. But the creatures that live on Earth today might have not lived here thousands of years ago. This is because the diversity on Earth is always changing.
The theory of evolution describes the slow change in organisms that occurs over many generations. Natural selection is the process by which organisms change over time, those best suited to their environment survive to pass their traits to the next generation.
Scientists have a system to keep track of all the organisms on Earth, they organize the organisms by grouping them based on their characteristics this is called classification.
When speaking about a certain KIND of organism, you are really talking about a certain organism, or species. Species typically live in the same area creating a Population. An Example: mice living in a small meadow are an example of population.
For any population to thrive, there must be enough food, water, and living space. Such factors are called Limiting Factors because they limit how many organisms can live in an environment.
Energy and Matter in Ecosystems
Different species, or kinds, of organisms living together interact with one another, The relationships they form can be divided into three main categories: Competition, Predation, or Symbiosis.
The set of organisms that occupy an area is constantly changing. The natural process by which one community of organisms slowly replaces another in certain area which is called an ecological succession
Organisms live almost everywhere on Earth. The part of Earth that supports life is called the biosphere, that also contain multiple climates. Specified as a biome, which is a large region characterized as having a distinct climate and specific types of plant and animal life.
This is a system used to organize into groups the many different organisms found on Earth. The groups that have the largest number of organisms is called domains, the second is higesis called a kingdom. The kingdom is broken down into six smaller levels phylum, class, order, family, genus, and species.
The different kingdoms are plants, animals, fungi, protists, eubacteria and archaebacteria.The plant kingdom is made up of many cells that are surrounded by cell walls. The animal kingdom also has many cells and is divided into two groups invertebrates (no backbone) and vertebrates (with backbone). Fungi are single or many-celled organisms that reproduce by spores. Protists are made up of one-celled organisms and many-celled organisms. And archaebacteria and eubacteria are single-celled organisms that lack a true nucleus.
Major Grouping of Organisms
One way to classify organisms is according to their place within the kingdoms. It is helpful to group them based on general characteristics. For an example you can create a group for organisms who make their food and organisms that don't. Animals who make their food are called autotrophs, animals who cant are called heterotrophs. Other ways organisms can be classified is prokaryotes and eukaryotes (contain or don't contain distinct, membrane-bound structures), vertebrates and invertebrates (backbone or no backbone), and vascular and nonvascular plants (have or don't have true roots, stems, or leaves).
A goal of classification is to show what ancestors organisms have in common.Relatioships between organisms can be shown in a taxonomic tree. In this common branches show groups of organisms that are closely related in their evolutionary history. Organisms separated by many branches are less closely related.
Using an Identification Key
An identification key can help you identify different types of organisms. A special key, called a dichotomous key, helps you identify organisms by presenting you with a series of choices. The choices describe characteristics of the organism your identifying. Your choices will eventually lead you to the identity of the species.
We give credit to the ScienceSaurous, found in the back shelf of the classroom.