Biology Notes.

 Chapter 1. A view of life.

 

1.1  How to define life.

 

Living things are organized.

-          cell, the smallest, most basic unit of life.

-          A cell is composed of nonliving chemicals

-          In multicellular organisms, similar cells combine to form a tissue, tissues form organs, organs form systems, systems are joined within an organism

-          Organisms form communities.

-          Communities form ecosystems

-          Ecosystems for biosphere.

Living things Acquire materials and energy

-          Energy is the capacity to do work, and it takes work to maintain the organization of the cell and the organism.

-          The term metabolism encompasses all the chemical reactions that occur in a cell.

-          Photosynthesis, a process that transforms solar energy into chemical energy in the bonds or organic nutrient molecules.

-          Homeostasis, the maintenance of internal conditions within certain boundaries.

Living things Respond

-          Interacting with their surroundings.

Living things reproduce and develop

-          Reproduce; make another organism just like itself.

-          Bacteria, protists, and other unicellular organisms split in two.

-          Genes, which contain specific info for how the organism is to be ordered, are made of long molecules of DNA.

Living things have adaptations.

-          Organisms become modified over time by a process called natural selection.

-          Certain members of a species, defined as a group of interbreeding individuals, may inherit a genetic change that causes them to be better suited to a particular environment.

-          Evolution is descent with modification.

-          One species can be common ancestor to several species.

 

1.2  How the biosphere is organized.

                               

-          The organization of life extends beyond the individual to the biosphere, the zone of air, land, and water at the surface of the earth where living organisms are found.

-          Individual organisms belong to a population, all the members of a species within a particular area. The populations of a community interact among themselves and with the physical environment, there by forming an ecosystem.

-          Because energy flows and does not cycle, ecosystems could not stay in existence without solar energy and the ability of photosynthesizes to absorb it.

 

The human population

 

-          modify existing ecosystems for its own purposes.

-          Human beings depend on healthy ecosystems for food, medicines and various raw materials.

-          Ecologists believe ecosystems cannot function properly unless they remain biologically diverse.

 

Biodiversity

 

-          Biodiversity is the total number of species, the variability of their genes, and the ecosystems in which they live.

-          Extinction is the death of a species or larger taxonomic group. 

 

1.3 How living things are classified

 

-          Taxonomy is the discipline of identifying and classifying organisms according to certain rules.

Categories of classification

-          Species, genus family, order, class, phylum, kingdom, domain.

-          There are 3 domains :

1.      domain bacteria

2.      domain Archaea

3.      Domain Eukarya

-          Both domain bacteria and archaea contain unicellular prokaryotes.

-          Prokaryotes are structurally simple but metabolically complex.

-          Kingdoms:

1.      protists

2.      fungi

3.      plants

4.      animals

-          Biologists give each living thing a two-part name called a binomial name.

 

1.3  The process of Science

 

-          Biology is the scientific study of life.

-          Scientific process often involves the use of scientific method, which begins with observation.

Observation

-          Scientists believe that nature is orderly and measurable, that natural laws, such as the low of gravity, do not change with time

-          Phenomenon, natural event

Hypothesis

-          Inductive reasoning occurs whenever a person uses creative thinking to combine isolated facts into a cohesive whole.

-          In this way, a scientist comes up with a hypothesis, a possible explanation for a natural event.

Experiments/ further observations.

-          Testing a hypothesis involves either conducting an experiment or making further observations.

-          Deductive reasoning involves “if, then” logic.

-          The manner in which a scientist intends to conduct an experiment is called the experimental design.

-          A control group, or simply the control, goes through all the steps of an experiment but lacks the factors being tested.

-          Model, a representation of an actual object.

-          The results of an experiment are referred as data.

Conclusion

-          Scientists must analyze the data in order to reach a conclusion as to whether the hypothesis is supported or not.

Scientific theory

-          The ultimate goal of science is to understand the natural world in terms of scientific theories, which are concepts that join together well-supported and related hypotheses.

-          Principle, a term sometimes used for theories that are generally accepted by an overwhelming number of scientists.

A controlled study

-          Controlled studies ensure that the results are due to the experimental variable, the component being tested. The results are called the dependent variable.