Three Domains of Life

1. Three Domains of Life

2. Eukaryotic origin of cells • The nucleus and endoplasmic reticulum of eukaryotic cells arose from an infolding of the prokaryotic cell membrane

3. Sound familiar??? • Other eukaryotic organelles originated from symbiotic prokaryotes • Mitochondria were once heterotrophic prokaryotes • Chloroplasts were once photosynthetic prokaryotes • Each has its own DNA and a double membrane

4. Domain Eukarya • Remember, all eukaryotic cells have a nucleus (the one exception are red blood cells) and complex organelles • Eukaryotic organelles can either be autotrophic or heterotrophic, may be unicellular or multicellular, and may reproduce asexually or sexually • So how do we distinguish amongst them?

5. Domain Eukarya consists of Kingdoms Animalia, Plantae, Fungi, and Protista Protista All unicellular

6. Kingdom Protista • Eukaryotic • Largely unicellular withmulticellular ‘exceptions’ • May be autotrophic or heterotrophic • Multicellular protists are distinguished from other Kingdoms by their lack of specialized tissues • Debate over classification

7. Kingdom Protista

8. Kingdom Fungi

9. Kingdom Fungi • Eukaryotic • Heterotrophic; Important decomposers • Unicellular and multicellular • Includes many disease-causing organisms • Others are important symbionts and fermenting organisms

10. Kingdom Fungi • Cell walls are composed of chitin • All fungi are heterotrophic • Obtain their food by secreting digestive enzymes and absorbing the nutrients released by the enzymes • Multi-cellular fungi consist of long, slender filaments, which grow through and digest its substrate (Fungi live in their food!)

13. Kingdom Fungi • The long filaments (called hyphae) can form complex structures • A mushroom is a spore-bearing body composed of hyphae

14. Kingdom Fungi • Spores can withstand degradation and survive for long periods of time, and because of their size, they can travel long distances • Example: Chestnut Blight; a fungal disease which has virtually eliminated the American chestnut • Accidentally introduced into the U.S. on imported lumber from Asia • Unknown spreading agent (the spores are everywhere!)

15. …Jack Frost nippin’ at your nose… • The American chestnut once covered large tracts of forest in the U.S. • The chestnut was a very important source of food for wildlife (and the inspiration for at least 1 Christmas song…) http://www.kychestnut.org/images/openGrownTree.jpg

16. The Chestnut Blight • Only a few mature survivors remain of the American Chestnut, which once consisted of 4 billion trees (that’s over 99.99% gone) • If you have ever eaten a chestnut, you are eaten a European import; only our grandparents may have ever tasted an American chestnut • The American Chestnut Foundation seeks to restore the great chestnut, but how?

17. The Chestnut Blight • Development of blight-resistant American chestnuts is accomplished through a process known as “backcross breeding” • Hybrids between American and Chinese chestnuts are repeatedly crossed back onto purely American specimens, yielding offspring which are blight- resistant • The resulting offspring are ~94% American (6% Chinese) and disease-resistant

18. Why did the mushroom go to the party? Because he was a fungi… • Many fungi live underground, and can reach great sizes • One of the largest living organisms in the world is a fungus! • The largest known specimen covers more than 3.4 square miles and is thousands of years old • And some species of fungi are bioluminescent!

19. Armillaria fungus Connected underground by hyphae!

20. Fungal symbioses • A lichen is a symbiotic association between a fungus and a photosynthetic partner (usually green algae or cyanobacteria)

21. Fungal symbioses • ~90% of all known species of vascular plants are involved in symbiotic associations with fungi • The long hyphae of the fungi function as an extension of the plant root system; increasing surface area for absorption of nutrients; very important! • The plant, in return, supplies organic carbon to the fungus

22. And just in case you didn’t believe me… http://www.flickr.com/photos/kellyslittlepieces/2243322652/

23. Kingdom Plantae • Eukaryotic • All multi-cellular • Cell walls made of cellulose • Autotrophic

24. Kingdom Plantae • Some plants produce seeds • Embryo of plant develops inside protective seed • Seed protects embryo from drought, aids in its dispersal, and creates a dormant stage, that allows the embryo to survive until environmental conditions are favorable for growth (why sunflower seeds don’t grow into sunflowers in their packages, but they will if you water them!)

26. Seed dispersal nationalzoo.si.edu/AnimalsBackyardBiology/UrbanNatureWatch/Watches/PlantAdap...ersal.cfm http://www.uni-heidelberg.de/institute/fak14/ipmb/phazb/birdsberries.htm http://www.ise514.org.uk/members/Photos/Plants/seed%20dispersal/fruit%20bat%20on%20%20fig.JPG www.flickr.com/photos/elancel/3608295338/

27. Kingdom Plantae • Seeds may be produced ‘naked’, or be produced by flowering plants • Plants with naked seeds are called Gymnosperms • Flowering plants are called Angiosperms

28. Angiosperms produce flowers • The ovary later develops into a fruit

29. http://www.flickr.com/photos/41019338@N00/2808113879/

30. Kingdom Animalia • Eukaryotic • Multicellular (unlike most Protists) • Lack cell walls (unlike Plants) • Heterotrophic, by ingestion – Animals obtain their nourishment by ingesting other organisms (unlike Fungi)

31. Kingdom Animalia • Most animals are mobile • Sexual reproduction dominates, but some simple animals can reproduce asexually (e.g., Hydra) • Animals have tissues; cells are organized into structurally functional tissues

32. Kingdom Animalia • Animals include • Fish • Amphibians • Reptiles • Birds • Mammals • And many invertebrates (insects, crustaceans, jellyfish, sponges, etc)

33. Want to learn more??? • Become a BIO major and take my BIO 152 class!!!

34. So long and thanks for all the fish… Thanks for listening!!! How penguins pose for my photographs in Antarctica