Welcome to biology Evolution, Homeostasis and Reproduction (the first lecture)
What is unique to life? Cell membrane contains protoplasm inside, is alive outside is dead (1) Complex - Cells have very complex macromolecules (DNA, RNA, protein) Entropy (disorder) increases But biology encloses small systems with awesome complexity
Life s properties (continued) (2) Movement, Responsiveness (irritability, sensitivity, excitability) (3) Development, Growth, Form (4) Metabolism - exchange energy -Catabolic (breakdown) -Anabolic (build-up)
(6) Homeostasis (regulation) Example#1 Thermostat, servo mechanism, negative feedback. Example#2 Weight regulation 1 extra cookie/day = 25 lb/yr
(7) Evolution is major unifying principle Life on Earth is 3 1/2 billion yrs old (presumably all organisms have common ancestor) History from primordial "soup" of molecules to biology, extinctions, etc.
(8) Reproduction Survival in biology is to and reproduce AND produce fertile offspring. Example#1- One species definition: Reproduce, fertile offspring Horse - donkey (differenty species) mate to produce the mule -- the mule is sterile:
Reproduction Example#2- Consider this: energy devoted to reproduction reproductive structures constitute most of the human diet grain, fruit (and vegetables that are fruits), dairy products and eggs.
Bacteriophage reproduction (a virus that "eats" bacteria). Is a virus alive? Compare terms "infectious" with "living." Is virus oldest form of life (so simple)? (Protein and DNA) No, it cannot be because it is a Parasite and therefore could not exist until its host existed.
Hershey Chase Experiment (Alfred Hershey & Martha Chase 1952) radioactive sulfur labels protein only seen in protein coat of bacteriophage radioactive phosphorus labels DNA only seen inside bacteria (where DNA is orchestrating the manufacture of new virus)
Scientific American Are viruses alive? Not all viruses are exactly like the bacteriophage. This paper will show you how some enter the cell (in contrast with Hershey-Chase result) Some viruses use RNA instead of DNA.
animal, vegetable or mineral once, 2 kingdoms were proposed (plants and animals), some have properties of both kingdoms Now 5 are generally accepted. Sometimes more are also proposed. How can the number of kingdoms be subject to debate? Classification is not an exact science.
Monera (prokaryotes) very diverse (2 of the 3 domains) cells do not have a nucleus suffix "karyote" refers to the nucleus, comes up in words like "perikaryon" (the part of a nerve cell near its nucleus) also "karyotype" (the chromosomal constitution of a cell).
eukaryotes Cells have a nucleus and organelles Protista (single celled "plants" and "animals") are also very diverse Fungi Plants Animals
Do they make their own food? Autotroph (self-feeder) Heterotroph (other-feeder) Food web
Phylogeny vs Taxonomy Taxonomy ("Systematics ) Linnean system (Linnaeus 1705-1778 botanist) Table 18-1 Kingdom - Phylum - Class - Order - Family - Genus - Species
binomial nomenclature Genus - Species: Homo sapiens people Drosophila melanogaster fruit flies Canis familiaris dogs
It is actually a graph. Diversity is on the X axis (abscissa). diversity in this example is location on Earth. The Y axis (ordinate) is time with long ago on the bottom and now on top split up into epochs of the geological time scale (Eocene, etc.). animals lower in the diagram are not just "simpler" animals of today today's animals are only at the top, further down may be extinct, horses in New World were re-introduced.
Evolution diagram branches out, "divergent evolution," so fundamental that you should see it now concept is that of homology wing of a bird and the flipper of a porpoise are homologous and are descended from the same common structure that led to your arm and hand. Molecular biologists borrowed this strategy