Theory of Evolution by Natural Selection

1. Theory of Evolution by Natural Selection One of the 8 characteristics of life

2. Evolution • Evolution- the process by which modern organisms have descended from ancient organisms due to gradual changes over time • Who was the main contributor to the theory of evolution?

3. Charles Darwin proposed that… • Fitness is a result of adaptations • Fitness - ability of an individual to survive and reproduce • Adaptations - characteristics that increase a chance of survival in their specific environment • Variation can be inherited • Variation – differences among organisms • Organisms produce more offspring than can survive. • They compete for limited resources • Individuals best suited to their environment survive and reproduce most successfully, passing their heritable traits to their offspring • other individuals die or leave fewer offspring • Species alive today are descended with modification from ancestral species • Organisms are related to ancestors but there have been changes over LONG, LONG periods of time

4. Natural Selection results in change • Over time natural selection results in changes in the inherited characteristics of a population. • These changes increase a species’ fitness in its environment. **Natural Selection cannot be seen directly- it can be observed as changes in a population (one species) over many successive generations**

5. Less Fit Genes More Fit Genes • The frequency of genes that improve the chance for survival and reproduction will increase in a population’ gene pool (become more common) • Webbed feet on aquatic mammals • Sharp tearing beak on a hawk • Coloring or markings that camouflages an animal • Resistance of weeds to herbicides • The frequency of genes that reduce the chance for survival and reproduction will decrease in a population’s gene pool (become less common) • Short legs on an animal that needs to run • Health problems in animals • Plant susceptibility to chemicals • Poor eye sight

6. Evolution is NOT • getting used to the hot weather in Florida • a duck becoming a better swimmer • because organisms “need” or “want” to change • wanting to develop new traits to fit into your environment

7. Now that we understand evolution, how do we keep these organisms organized? • We use a 6 kingdom classification system • We look at • cell type/complexity of the cell • function of the organism • mode of nutrition (how does it obtain food) • …and others!

8. KINGDOM: Archaebacteria“extremophiles” • Kingdom made up of single celled bacteria that live in extreme environments (hot, salty, chemical-filled) • Can be heterotrophs or autotrophs • ex. Bacteria that live in hot springs • Lack most organelles but have ribosomes

9. Eubacteria • Kingdom that contains all of the single celled prokaryotes except the Archaebacteria; they live in water, soil and even the human body (cause diseases and found in food)! • Lack most organelles (have ribosomes) • Can be heterotrophic or autotrophic • Cell wall of peptidoglycan • Ex. Escherichia coli (E. coli O157:H7)

10. Protista • Kingdom of mostly one-celled eukaryotic organisms that are different from plants, animals, fungi and bacteria • Contain cilia, flagella, pseudopodia • Mostly single-celled • Can be heterotrophic or autotrophic • Can be plant-like (algae, euglena), animal-like (amoeba, paramecia) or fungi-like (mildew)

11. Fungi • Kingdom of non-green heterotrophic, eukaryotic that are multicellular (except for yeast which is unicellular) • organisms do not move • Cell wall of chitin • Break down substances in their surroundings using enzymes and absorbing the nutrients • Ex. Morchellaesculenta

12. Plantae • Kingdom made up of complex, multicellular organisms that are naturally green (chloroplasts containing chlorophyll), have cell walls made of cellulose, cannot move, and use the sun’s energy to make sugar by means of photosynthesis • Ex. Fruits and vegetables

13. Animalia • Kingdom made up of complex multicellular organisms that lack cell walls, can usually move and quickly respond to their environment • Ex. Sponges, jellyfish, insects, worms, starfish, corals, fish, amphibians, reptiles, birds, mammals, humans

14. 3 domain classification system • Archaea—prokaryotes; includes kingdom Archaebacteria • Bacteria—prokaryotes; includes kingdom Eubacteria • Eukarya—eukaryotes; includes kingdoms Protists, Fungi, Plants, and Animals

15. Taxonomy: classifying and identifying organisms Kingdom Phylum Class Order Family Genus Species 7 major levels of taxonomy

16. King-dom, Phy-lum, Class-and-Order Fam-ily, Ge-nus, Spe-cies Yan-kee Doo-dle Went-To-Town Rid-ing On-A Po-ny Ways to remember KPCOFGS

17. What happens as we go from Kingdom  Species? • Kingdom – Most broad level • Species – Most specific level

18. Questions • Which would have a larger number of individuals, a Class or a Family? • Class • Which are more closely related to each other, members of the same class or members of the same phylum? • Same Class

19. What do we call it when we give an organism two names? Binomial Nomenclature

20. What are the rules for naming? • Italicize (typing) or underline (written) • Capitalize genus and lower case species • Genus is always listed first and species is listed second

21. Examples Homo sapiens (human) Canisfamiliaris (dog) Canis lupus (gray wolf)

22. Which 2 organisms are most closely related based on their names? • Viciafaba(broad bean) • Glycine max (soybean) • Phaseolusvulgaris(kidney bean) • Hordeumvulgaris(barley) • Phaseoluscoccineus(scarlet runner bean) • Phaseolusvulgarisand Phaseoluscoccineus • REMEMBER WE LOOK AT GENUS NAME FOR RELATIONSHIPS