Human Biology BIOL 104 Talk one Biological Perspective
Human Biology (BIOL 104) Talk one: Biological Perspective To get you thinking and talking
Levels of Biological Organization The biological levels of organization of living things. From a single organelle to the entire biosphere, living organisms are parts of a highly structured hierarchy. credit “organelles”: modification of work by Umberto Salvagnin; credit “cells”: modification of work by Bruce Wetzel, Harry Schaefer/ National Cancer Institute; credit “tissues”: modification of work by Kilbad; Fama Clamosa; Mikael Haggstrom; credit “organs”: modification of work by Mariana Ruiz Villareal; credit “organisms”: "Crystal"/Flickr; modification of work by credit “ecosystems”: modification of work by US Fish and Wildlife Service Headquarters; credit “biosphere”: modification of work by NASA) Copyright: Open. Stax Biology for AP Courses, Open. Stax, and Rice University
The scientific method • First documented by England’s Sir Francis Bacon (1561– 1626) who set up inductive methods for scientific inquiry. • Biologists study the living world by posing questions about it and seeking science-based responses. • This approach is common to other sciences as well and is often referred to as the scientific method. Copyright: Open. Stax Biology for AP Courses, Open. Stax, and Rice University Sir Francis Bacon (1561– 1626) is credited with being the first to define the scientific method. (credit: Paul van Somer).
The scientific method • Typically starts with an observation (often a problem to be solved) that leads to a question. • A hypothesis is a suggested explanation that can be tested. To solve a problem, several hypotheses may be proposed. • A valid hypothesis must be testable. It should also be falsifiable, meaning that it can be disproven by experimental results. • Importantly, science does not claim to “prove” anything because scientific understandings are always subject to modification with further information. Copyright: Open. Stax Biology for AP Courses, Open. Stax, and Rice University
Scientific theories • Animals, plants, and bacteria are examples of living systems that share many properties distinguishing them from nonliving things. These properties are branched into theories. Cellular organization Fundamental unit of life is the cell – all living things are made up of cells. Metabolism Living things take up energy-rich materials and give out waste to environment. Some energy fuels life processes some accumulates and is released after death. Selective response Living things respond selectively to stimulation in the environment. Organisms recognize certain chemicals as nutrients while ignoring others.
Scientific theories Homeostasis Living systems have some capacity to change harmful conditions into conditions more favorable to their continuing existence – the conversion of chemical compounds. Growth and biosynthesis Living systems go through phases during which they make more of their own material. Genetic material Living systems contain genetic material (DNA and RNA) to allow inherited traits. Reproduction Living systems can reproduce & pass on genetic material. Population structure Organism form populations. Of these organism capable of sexual processes, a population is all those organisms that can interbreed with one another.
Ethical thinking • Ethics is a discipline dealing with the analysis of moral rule and the ways in which moral judgments are made and justified. • Would you park your car in this space? • Why? From the wikimedia free licensed media file repository
What benefits could come from nuclear power? • Nuclear power plants emit less than 1/100 th the greenhouse gases of coal or gas power stations • Nuclear energy has the lowest harmful impacts on the environment - do not emit harmful gases - does not burn anything to produce electricity • Nuclear energy is the most "ecologically efficient“ of all energy sources • Produce the most electricity in relation to its minimal environmental impact • The nuclear energy also does not produce carbon dioxide or other greenhouse gases which can cause global warming Used with permission from Think Global Green
Chernobyl Nuclear Disaster • April 26, 1986 in the Ukraine, • It is regarded as the worst accident in the history of nuclear power. • A plume of radioactive fallout drifted over parts of the western Soviet Union, Eastern and Western Europe, Scandinavia, the British Isles, and eastern North America. Large areas of Ukraine, Belarus, and Russia were badly contaminated • Resulted in the evacuation and resettlement of over 336, 000 people. About 60% of the radioactive fallout landed in Belarus, according to official post-Soviet data From the wikimedia free licensed media file repository
Chernobyl Nuclear Disaster • Two hundred people were hospitalized immediately, of whom 31 died (28 of them died from acute radiation exposure). • Most of these were fire and rescue workers trying to bring the accident under control • At least 8, 000 people have died, most from radiation-related diseases. • About 2, 000 people have been diagnosed with thyroid cancer and between 8, 000 and 10, 000 cases are expected to develop over the next 10 years. From the wikimedia free licensed media file repository
Chernobyl Nuclear Disaster From the wikimedia free licensed media file repository
Chernobyl Nuclear Disaster thepurebar. com forum. prisonplanet. com
Rights • Do animals have rights? • Nearly all new drugs, cosmetics, food additives, new forms of surgery are tested on animals first • Many societies have historically denied even the most basic of rights to classes of persons on the basis of economics, gender, race, ethnicity, or religious beliefs From the wikimedia free licensed media file repository
Experiments without consent • Humans as experimental subjects • Experiments on twins • Bone, muscle, and nerve transplantation experiments • Head injury experiments • Freezing experiments • Malaria experiments • High Altitude and pressure experiments From the wikimedia free licensed media file repository
Experiments without consent • 1932 The Tuskegee Syphilis Study begins. • 200 African-American men infected with syphilis are never told of their illness, are denied treatment, and instead are used as human guinea pigs in order to follow the progression and symptoms of the disease. Charlie Pollard • 95% all subsequently die from syphilis, their families never told that they could have been treated. • Voluntary informed consent – Both a moral and legal issue • As there are lawyers under every rock! Herman Shaw From the wikimedia free licensed media file repository
Thalidomide • Gender bias – What happens if this is not considered – It was only in 1992 that women were included in medical trials of new drugs by law! • Thalidomide (Kevadon®) – Developed as a morning sickness drug in the 1950 s – BUT – never tested on women • Led to a generation of deformities From the wikimedia free licensed media file repository
So, how did Thalidomide affect DNA? • So, things to remember: • All genes are coded for at the genetic level by four nucleotide bases (A, C, G, and T) and each gene has a unique coding and relative ratio of these bases. • Gene expression is highly regulated: – Promoters, enhancers, and repressors • In limb development, the genes involved have a VERY HIGH relative ratio of guanine (G).
Thalidomide • The structure of thalidomide is similar to that of the DNA purine bases adenine (A) and guanine (G). • In solution, has almost no affinity for the other nucleotides, cytosine (C) and thymine (T). • Furthermore, thalidomide can intercalate into DNA, presumably at G-rich sites. From the wikimedia free licensed media file repository
Thalidomide • Thalidomide or one of its metabolites intercalates into these G-rich promoter regions, inhibiting the production of proteins and blocking development of the limb buds. • This intercalation would significantly affect the genes that rely primarily on guanine (G) sequences. • Most other developing tissues in the embryo rely on pathways without guanine, and are therefore NOT affected by thalidomide From the wikimedia free licensed media file repository
Thalidomide • In UK alone there were 12, 000 victims. • Sometimes functional feet and hands were amputated to allow the fitting of lower- and upper-limb Prosthesis in order for the children to appear “normal”. • Special school were set up too, in an attempt to keep the children out of sight and out of the minds of the public. From the wikimedia free licensed media file repository
Thalidomide • Victims of the 1970 s Thalidomide scandal have passed their deformities on to their children. • Thalidomide altered the coded regions for limb development in the G-rich promoter regions of the victims to replication of these regions during the production of gametes during Meiosis • – so arms and legs are not developed! From the wikimedia free licensed media file repository
Thalidomide, Still? !!!!!! • Still in use today • Cancer treatments – by cutting off the flow of blood to tumors • Leprosy – is an infectious disease caused by a DNA plasmid – invades human nerves. – If untreated can eventually cause a variety of skin problems, loss of feeling, and paralysis of the hands and feet . From the wikimedia free licensed media file repository
Genetically modified crops • All plant characteristics, such as size, texture, and sweetness, are determined on the genetic level. • • • Also: The hardiness of crop plants. Their drought resistance. Rate of growth under different soil conditions. Dependence on fertilizers. Resistance to various pests and diseases. • Used to do this by selective breeding
Genetically modified crops • Agrobacterium method – Uses the natural infection mechanism of a plant pathogen – Agrobacterium tumefaciens naturally infects the wound sites in dicotyledonous plant causing the formation of the crown gall tumors. – Capable to transfer a particular DNA segment (T-DNA) of the tumor-inducing (Ti) plasmid into the nucleus of infected cells where it is integrated fully into the host genome and transcribed, causing the crown gall disease. • So the pathogen inserts the new DNA with great success!!!
What people think of using GM Plants! • Survey carried out by: – The Scientist Magazine. • Feb 2004, No/15401 • 302 readers responded to survey • Yes, a small group, as there are seven billion people on the planet • Interesting questions! • What to YOU think? The Scientist Magazine
Genetically modified crops • Issues: • Destroying ecosystems – tomatoes are now growing in the artic tundra with fish antifreeze in them! • Destroying ecosystems – will the toxin now being produced by pest-resistance stains kill “friendly” insects such as butterflies. • Altering nature – should we be swapping genes between species?
Genetically modified crops • Issues: • Vegetarians – what about those tomatoes? • Religious dietary laws – anything from a pig? • Cross-pollination – producing a super-weed • Human health – what of the antibiotic marker gene?
The End. Any Questions?
- Slides: 28