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ENVIRONMENTAL SCIENCE Exam I Powerpoint. Environmental Science. is the study of how the natural world works, how we are affected by the environment and how humans impact the environment.
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Environmental Science is the study of how the natural world works, how we are affected by the environment and how humans impact the environment. In order to better understand how environmental science affects the biosphere, we need to first look at a few of the basic principles of Biology in general.
The environment is affected by both abiotic (non-living) and biotic (living) factors.
Humans are part of the environment not separated from it. However, our modern way of life makes it easy to forget that humans are not separate from the environment.
A healthy environment has well-functioning ecological systems that provide clean air, clean water, comfortable climatic conditions, and an adequate ability to deal with wastes.
Unfortunately humans can disrupt ecological systems and their functions through our activities such as disruption of water cycles, overuse of nonrenewable resources, near exponential population growth, and adding more waste than the system can handle.
We will look at the various natural resources (renewable and nonrenewable), sustainability, the impact of the exponential population growth of Homo sapiens, the problems that arise from our use of resources and other daily activities, and the relationship between the environment and other disciplines of study
Scientific Discovery Regardless of the area of interest, scientists make their discoveries by: 1. observations where they document some phenomenon (e.g., Jane Goodall’s work with chimpanzees) 2. controlled experiments which often involve hypothesis testing.
The Scientific Method • Make Observations • Ask a Question • Propose Hypotheses and Predictions • Design Experiment and Test hypotheses • Apply Statistical tests to results • Make inferences based on results • Report, ask new questions
Biodiversity and the Three Domains of Life
Definitions Biodiversity - number of species of living organisms in a given area A species is composed of organisms that appear to be similar (in looks) and that are capable of interbreeding with other like individuals. This is the Biological Species Concept proposed by Ernst Mayr.
More Definitions Autotrophs are organisms that are capable of building their own large organic molecules by using CO2 and energy from their environment. Heterotrophs are organisms that are not capable of synthesizing their own food and thus obtain their nourishment from autotrophs, other heterotrophs or from organic wastes (e.g., decomposers).
Viruses. Not considered to be living (they cannot reproduce on their own) by many biologists, they are worth mentioning. A virus is a noncellular infectious agent possessing a nuclei acid core that cannot reproduce itself. Viruses may be composed of DNA or RNA within the protein coat (but
Domains Archaea and Bacteria - bacteria, all are prokaryotic (meaning that they do not possess membrane-bound organelles), autotrophs (photosynthetic and chemosynthetic) and heterotrophs.
Protists - mostly single-celled eukaryotes but there are some colonial forms as well as some that are truly multicellular (the algae). Some are heterotrophs & some are photosynthetic autotrophs.
Kingdom Fungi (Myceteae) - predominantly multicellular eukaryotes. They have external digestion and all are heterotrophs.
Kingdom Plantae plants. All are eukaryotic and the vast majority are photosynthetic autotrophs
Kingdom Animaliae animals ranging from sponges to humans. They are multicellular eukaryotes and all are heterotrophic
Biodiversity in danger ?? An investigation into the causes of endangerment for 877 species in the United States found that the vast majority were caused by expansion of human economic activities. Economic growth beyond what contributes to human well being is wasteful of biodiversity, as well as resources.
Biodiversity is declining but what to do about that is controversial
Each organism possesses a highly ordered structure even if they may seem very simplistic (like prokaryotic cells and single celled eukaryotes). The cell theory states that all organisms are composed of one or more cells which are the basic units of organization and which arise from pre-existing cells
Some Components of Cells Cell Membranes (found in both prokaryotes and eukaryotes
Cell membrane continued Function - basically these membranes serve as barriers which allow some substances to move in and out and prevent other substances from such movements, also they function in recognition (e.g., self for the immune system). Movement of substances can be classified under the following categories
Nucleus (plural nuclei) (not found in prokaryotes)
Function Membrane - functions as a barrier (see discussion of plasma membrane) Nucleolus - the formation of ribosomes chromosomes - contain genes whose expression leads to the formation of proteins which in turn control all aspects of an individual either directly or indirectly (e.g., through the ability to learn). nucleoplasm - the cytoplasm or fluid medium of the nucleus Remember that prokaryotes do not have their chromosomes packaged within nuclei, but instead the DNA of prokaryotes is found in a nuclear area.
Ribosomes found in both prokaryotes and eukaryotes but with structural differences. Structure - small consisting of a large and a small subunit (chemically made up of rRNA and proteins) Function - the sites of protein synthesis
Mitochondria • Structure – cigar-shaped, double membrane-bound organelle • Function – Energy transfer by ATP synthesis
Chloroplast • Structure • Also cigar or spindle shaped, double membrane-bound, green • Function • Site of photosynthesis
There are other structures but we will not be covering them.
Cool video http://video.google.com/videosearch?gbv=2&hl=en&q=nervous%20tissue&ie=UTF-8&sa=N&tab=iv#q=life+in+a+cell+harvard&hl=en&emb=0
XP sufferers are born with DNA that cannot repair cell damage that occurs from everyday exposure to ultraviolet radiation coming from sunlight, daylight (including shade), and fluorescent and halogen lighting. Even a few moments of exposure to daylight can cause severe 2nd degree burns that eventually become skin cancer. Patients with XP rarely live to adulthood. Currently, there is no cure for XP. The DNA damage is cumulative and irreversible.
DNA And Reproduction
Genes are portions of DNA molecules that contain genetic information which controls protein synthesis.Each chromosome is made up of DNA and associated proteins. The DNA of each chromosome contains many genes.
The process whereby genes direct protein synthesis is called gene expression. DNA transcribed> RNA translated> protein
DNA structure DNA is composed of subunits which consist of a 5Carbon sugar (deoxyribose), phosphate group(s), and nucleotide bases (A, T, C, and G). The nitrogenous bases are adenine (A), thymine (T), cytosine (C) and guanine (G). Nucleotides are linked by sugar-phosphate bonds which basically form a backbone.
Most cells replicate or double their contents and then divide to produce two identical daughter cells. In addition, living organisms produce offspring however, in sexual reproduction the number of chromosomes in each of the parents is halved during the production of eggs and sperm and then the full number of chromosomes is restored when the sperm fertilizes the egg. That produces a zygote that undergoes development and growth into a new individual
Mutations are permanent heritable changes in DNA that can be passed from a parent cell within an individual and result in problems such as cancer or if gametes are involved the changes are passed from the parents to the offspring. Mutagens are chemical or physical phenomena that cause these mutations. Many of the hazardous or toxic materials can be classified as mutagens.
