5. Evolution and Biodiversity

1. 5. Evolution and Biodiversity • Central Concepts: Evolution is the result of genetic changes that occur in constantly changing environments. Over many generations, changes in the genetic make-up of populations may affect biodiversity through speciation and extinction.

2. 5.1 Explain how evolution is demonstrated by evidence from the fossil record, comparative anatomy, genetics, molecular biology, and examples of natural selection.

3. Chapter 15-1 The Puzzle of Life’s Diversity • 1809 Charles Darwin – Father of Evolution. Naturalist from England. Sailed on the surveying ship HMS Beagle and traveled to various lands. • During his travels, Darwin made numerous observations and collected evidence that led him to propose a revolutionary hypothesis about the way life changes over time.

4. Darwin’s Observations • üPatterns of Diversity – organisms seemed well suited to their environment! There were SO many different types of similar organisms (68 different types of beetles in the Brazilian rainforest).  Was there such way that leads to variety. Why were certain types or organisms only found in certain areas? How were they so well suited for their environment? • üLiving Organisms and Fossils – Darwin collected the preserved remains of ancient organisms from many places (fossils). Why have so many species disappeared and how were they related to living things. • üThe Galapagos Islands – One of the most influential places - off the coast of S. America. They were close together – they have very different climates very different organisms (from hot, dry à nearly barren; lots of plants à few plants).

5. ·Finches – 16 different types of birds – differed in color and beak shape (based on what they ate. oTortoises – varied from one island to another. Darwin observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos

6. 15-3 Darwin Presents His Case • Darwin put his thoughts and evidences into a book (title above). • Inherited variation and artificial selection • Artificial Selection – nature provided variation, and human selected those variations that they found useful. Horse/dog breeders; farm animals (breed the best ones – not the worst) • Natural Selection – process by which individuals that are better suited to their environment survive and reproduce most successfully (survival of the fittest) • üFitness – ability to survive and reproduce • üAdaptation – any inherited characteristic that increases an organism’s chance of survival. • üDescent with modification – over long time, natural selection produces organisms that have different structures, establish different niches, or occupy different habitats. (that’s why they look different from their ancestors)

7. EVIDENCES FOR EVOLUTION • Darwin argued that living things have been evolving on earth for millions of years.

8. FOSSILS • Preserved remains of ancient organisms • fossils lower in rocks and mountains are older than those in higher areas. They also show that organisms changed a LOT over time. Gaps remain in the fossil record.

9. HOMOLOGOUS BODY STRUCTURES structures that have different mature forms but develop the same embryonic tissue. Provide evidence that all four-limbed vertebrates have descended with modifications from common ancestors.

10. VESTIGIAL ORGANS • organs of many animals are so reduced in size that they are just vestiges, or traces of homologous organs in other species.  It may not affect an organisms ability to survive and reproduce, so natural selection did not eliminate the organ

11. EMBRYOLOGY early stages of embryos of many animals with backbones are very similar. They look really similar.

12. 4 Evidences for Evolution • 1. Fossils • 2. Homologous Structures • 3. Vestigial Organs • 4. Embryology

13. DARWINS THEORY • Individual organisms differ, some variation is heritable • organisms produce more organisms than survive • Organisms compete for limited resources • Most fit organisms survive • species alive today are descended with modification

14. 17-1 The Fossil Record • Paleontologists: scientists who study fossils • The fossil record provides evidence about the history of life on Earth. It also shows how different groups of organisms, including species, have changed over time. • 99.9% of anything that was ever living on this earth is now extinct.

15. Most fossils form in sedimentary rock, as shown in the figure at right. Sedimentary rock is formed when exposure to rain, heat, wind, and cold breaks down existing rock into small particles of sand, silt, and clay.

16. In relative dating, the age of a fossil is determined by comparing its placement with that of fossils in other layers of rock, as shown in the figure at right. Recall that sedimentary rock is formed from the gradual deposition of layers of sand, rock, and other types of sediment. The rock layers form in order by age—the oldest layers on the bottom, with more recent layers on top, closer to Earth's surface. • Relative dating allows paleontologists to estimate a fossil's age compared with that of other fossils.

17. 5.2 Describe species as reproductively distinct groups of organisms. Recognize that species are further classified into a hierarchical taxonomic system (kingdom, phylum, class, order, family, genus, species) based on morphological, behavioral, and molecular similarities. Describe the role that geographic isolation can play in speciation.

18. SECTION 18-1 Finding Order in Diversity • SCIENTISTS HAVE IDENTIFIED MORE THAN 2 MILLION SPECIES OF ORGANISMS ON EARTH, BUT ESTIMATE 40 MILLION SPECIES INHABIT THE EARTH. • ·        A Universal System is necessary to have clear communication among scientists worldwide. A system that required an International System for Classifying and Naming all organisms. • ·        2,000 years ago Greek philosopher Aristotleclassified things as either Plant or Animal and then as land dwellers, water dwellers and animal dwellers. • ·      Scientists found that Using COMMON NAMES, such as robin or fir tree, for an organism presented its own problems; common names varied from on locale to the next and common Names May Not describe species accurately. • ·Carols Linnaeus in the mid-1700s, Swedish Biologist established a simple system for classifying and naming organisms (taxology). He developed a Hierarchy for classifying organisms based on morphology (using what it looks like to categorize it)

19. Today we have SEVEN LEVELS OF CLASSIFICATION: • A. KINGDOM  (largest classification)    B. PHYLUM     C. CLASS    D. ORDER    E. FAMILY    F. GENUS    G. SPECIES  (smallest classification) KING PHILIP CAME OVER FOR GRAPE SODA.

21. ·BINOMIAL NOMENCLATURE is a 2 name system based on the organims’s genus and species. • SAMPLE:  Acer rubrum - RED MAPLE TREE • Acer is the Latin name for Maple (genus) • rubrum is the Latin word for Red (species) •     OR THE NAME CAN BE ABBREVIATED AS: A. rubrum. •     HUMANS ARE NAMED: Homo sapiens • Homo because of our large brain and upright posture. sapiensbecause of our intelligence and ability to speak.

22. CHAPTER 18-2 Modern Evolutionary Classification • When placing an organism into a Taxonomic Category, Modern Taxonomists May consider its:     • MORPHOLOGY (what it looks like)     • CHROMOSOMAL CHARACTERISTICS     • NUCLEOTIDE (DNA AND RNA) AND AMINO ACID SEQUENCES     • EMBRYOLOGICAL DEVELOPMENT     • FOSSIL RECORD  

23. SECTION 18-3, Kingdoms and Domains

24. THE SIX-KINGDOM SYSTEM

25. 5.3 Explain how evolution through natural selection can result in changes in biodiversity through the increase or decrease of genetic diversity within a population.

26. 16-3 The process of speciation • Factors such as natural selection and chance events can change the relative frequencies of alleles in a population. But how do these changes lead to the formation of new species, or speciation?

27. ISOLATING MECHANISMS: • Reproductive Isolation: As new species evolve, populations become reproductively isolated from each other and can no longer produce fertile offspring. • Behavioral Isolation: when two populations are capable of interbreeding, but have differences in courtship rituals or reproductive strategies that involve behavior. • Geographic Isolation: two populations are separated by geographic barriers such as rivers, mountains or bodies of water. • Temporal Isolation: two or more species reproduce at different times.

28. 17-4PATTERNS OF EVOLUTION • PATTERNS OF EVOLUTION • important topics in macroevolution are • EXTINCTION: 99.9% of all species ever on this earth are now extinct. Mass extinction. (most extinctions today are due to human activity) • ADAPTIVE RADIATION: a single species or small group have evolved into different forms that live in different ways. Ex. FINCHES, homologous structures

30. 3. CONVERGENT EVOLUTION: Unrelated organism come to resemble one another. Ex. Dolphin/sharks 4. COEVOLUTION: process by which 2 species are closely connected to one another by ecological interactions evolve together. Ex. Plants and plant eating insects

31. 5. PUNCTUATED EQUILIBRIUM: some groups of organism have evolved rapidly after a mass extinction