EVOLUTION & BIODIVERSITY TOPIC 5

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1 EVOLUTION & BIODIVERSITY TOPIC 5

2 TOPIC 5 EVOLUTION & BIODIVERSITY 5.1 EVIDENCE FOR EVOLUTION NATURAL SELECTION CLASSIFICATION FOR BIODIVERSITY CLADISTICS SAMPLE QUESTIONS... 18

3 5.1 EVIDENCE FOR EVOLUTION EVOLUTION The changes are and over The changes occur in controlled by The changes occur at a The evidence for evolution is strong, but it is still considered to be just a theory. The theory of evolution has stood up to repeated research, testing and evidence collection. The theory gets as new data emerges. Some examples of evidence for evolution: Also,, 1

4 THE FOSSIL RECORD of plants, animals and prokaryotes are able to be in of. The the fossils are found, the they are. The fossils could show a over time as a species develops. Transitional species have been uncovered. eg. is a transitional fossil between and Fossils are The of all and and their in forms the fossil record. The fossil record tries to create a to the study of fossils and evolution. There are in the fossil record: because because because Transitional species show the links between groups and species by traits/features common to the species and the theorised. eg. Archeopteryx lithographica has a combination of avian and reptilian features. 2

5 SELECTIVE BREEDING Also called The process by which humans breed organisms for. eg. breeding dogs for racing or herding eg. bred for yielding milk or meat eg. breeding crops for increased yield or HOMOLOGOUS STRUCTURES Comparing the of groups of organisms uncovers some structural features that are. These structures are referred to as. These similarities imply between the organisms. If these homologous structures are used in different ways by the different species, it implies into different. eg. the in 3

6 HOMOLOGOUS STRUCTURES Looking for trends and discrepancies There are common features in the bone structure of vertebrate limbs despite their varied use. The five-fingered limb was adapted by modification for different uses/habitats: Mammals for Birds for Amphibians for Reptiles for 4

7 DIVERGENT EVOLUTION of a species can into by evolution. If populations are, and therefore from one another, it is likely that they will experience. Over many generations, the population will change as a result of (Topic 5.2). If the continues to be for a long period of time, the separated populations will not be able to with each other even when they are. This is called. Populations can become reproductively isolated from one another by a of some description. The barrier could be: separated by a river or mountain range around at different times different mating rituals or calls prefer different food/plants aspects of environment favour one form over another Speciation can be or. used the of the as an example of speciation occurring in this way. 5

8 CONTINUOUS VARIATION Continuous variation of populations can exist across a This matches the concept of. eg. gulls are an example of a showing continuous variation where is able to occur The gulls in a ring around the. ie. Species 1 can breed with Species 2, Species 2 can breed with Species, etc However, Species 1 (Lesser black-backed gull - L. fuscus) is sufficiently different from (European herring gull - L. argentatus). These two species. THE PEPPERED MOTH Up until mid 19th century, most peppered moths were, but did exist. Their light colour allowed them to against on the trees and rocks. produced and. This soot covered the trees and killed then lichen. The black mutant was now able to camouflage against the soot-covered trees. Its population, while the population of white moths decreases due to by birds. NOTE: in Europe have and evolution of the peppered moth is now! Complete relevant practice Qs beginning on Page 18. 6

9 5.2 NATURAL SELECTION Finding, catching This causes a struggle for survival. Avoiding, tolerating Shelter, nesting sites Catching, avoiding Attracting, fertilising Resulting from 7

10 are that make an individual its and way of life. Variations that give an advantage are selected for: The individual which can best in the will survive long enough to and the trait. of these will and, the population will. Variations that give a disadvantage are selected against: The individual is to the environment, making it more for them to survive. The individual is to pass on the trait. Frequency of these genes will. Process of natural selection: 1. of offspring OR environmental change 2. exists in a population 3. for survival (due to ) 4. Advantageous variations are 5. to reproduce and pass on genes 6. Gene frequency increases and becomes more common in population Only changes in the characteristics of a population can be passed on. 8

11 EXAMPLES OF EVOLUTION Some species have a and can be. Most species have a generation time and the evolutionary changes are so there is only evidence for evolution. Examples of evolution: Theories can be used to explain natural phenomena The theory of evolution by natural selection can explain the development of antibiotic resistance in bacteria. Antibiotic resistant bacteria: Most individuals in a bacterial colony are. Mutations give rise to. Some of these variations will result in to certain. The resistant strain will. are passed on and the resistant population grows. eg. Staphyloccoccus aureus bacteria ( ) is usually treated with. There is now a methycillin-resistant strain of Golden Staph ( ). This is could cause big problems in the future, as bacteria could become resistant to antibiotics. Could create a colony of! Worried? Go study and research new antibiotics!!!!! 9

12 EXAMPLES OF EVOLUTION Darwin s finches: The Galapagos Islands are a group of islands, off the coast of. visited the islands in on. The finches evolved from a of finches on the mainland. Darwin believed that they might have been course to their new habitats by a. Each habitat had, so ( of years!), the finches to suit their own islands. They eventually became. This is. 10

13 EXAMPLES OF EVOLUTION The Island of is a small, isolated island susceptible to. There are two species of finches that have been studies for years on this island: ground finch ground finch original species on the island Large ground finch: Beak is large, ideal for. A ( La Niña event) resulted in a of seeds Consequence was a in the of finches The mean beak size of finches was. The mean beak size of successive generations. Medium ground finch: Beak is short and thick, ideal for small and medium seeds. (1983 El Niño event) resulted in an of smaller sized seeds Consequence was a in the mean beak size of successive generations. Complete relevant practice Qs beginning on Page

14 5.3 CLASSIFICATION FOR BIODIVERSITY U 1. The binomial system of names for species is universal among biologists and has been agreed and developed at a series of congresses. 2. When species are discovered they are given scientific names using the binomial system. 3. Taxonomists classify species using a hierarchy of taxa. 4. All organisms are classified into three domains. 5. The principal taxa for classifying eukaryotes are kingdom, phylum, class, order, family, genus and species. 6. In a natural classification, the genus and accompanying higher taxa consist of all the species that have evolved from one common ancestral species. 7. Taxonomists sometimes reclassify groups of species when new evidence shows that a previous taxon contains species that have evolved from different ancestral species. 8. Natural classifications help in identification of species and allow the prediction of characteristics shared by species within a group. A 1. Classification of one plant and one animal species from domain to species level. 2. Recognition features of bryophyta, filicinophyta, coniferophyta and angiospermophyta. 3. Recognition features of porifera, cnidaria, platylhelmintha, annelida, mollusca, arthropoda and chordata. 4. Recognition of features of birds, mammals, amphibians, reptiles and fish. S 1. Construction of dichotomous keys for use in identifying specimens. NOS Cooperation and collaboration between groups of scientists scientists use the binomial system to identify a species rather than the many different local names. Complete relevant practice Qs beginning on Page

15 5.4 CLADISTICS CLADOGRAMS Cladograms are that show the similarities and differences between different species. points on cladograms are called. Nodes indicate a between the remaining organisms with shared derived characteristics Cladograms are mostly based on or in a protein. Clade: Clades can be small or large Some members of a clade may be The used to build a cladogram can also be used to estimate species diverged from one another. in DNA that are occur at a. This rate can be used as a to calculate how long ago a species diverged. The, the more they shared. 13

16 CLADOGRAMS Primate cladogram: 1 What animal is most closely related to humans? 2 What animals are more closely related to humans than old world monkeys? 3 Which animal diverged from the primate ancestor first? 14

17 HOMOLOGOUS & ANALOGOUS TRAITS Traits can be homologous and analogous. ANALOGOUS HOMOLOGOUS Structurally Structurally Functionally Functionally evolution Examples evolution Examples 15

18 THE FIGWORT FAMILY Falsification of theories with one theory being superseded by another Plant families have been reclassified as a result of evidence from cladistics. 16

19 THE FIGWORT FAMILY Evidence from cladistics has shown that classifications of some groups based on did not with the of a group or species. eg. or family DNA evidence identified The members of the family were as a result Most Figworts have been reclassified into the closely related Plantain, Lopseed, and Broomrape families. Now all of these families are to, and the remaining genera in the Figwort family lack strong structural between them. Complete relevant practice Qs beginning on Page

20 SAMPLE QUESTIONS EVIDENCE FOR EVOLUTION Q1 Divergent evolution is often seen among species on different islands because: A. island populations are usually smaller and more affected by genetic drift. B. natural selection does not occur on islands. C. when islands are first colonised, many ecological resources are unused, allowing descendants of a colonising species to diversify so descendants have the adaptations that enable them to survive in many different parts of the environment. D. island species experience identical conditions on each of their respective islands Q2 New species arise from a common ancestor when A. populations of the ancestral species become geographically isolated from one another. B. populations of the ancestral species become reproductively isolated from one another. C. both A and B. D. neither A or B. Q3 Fossils are the preserved remains or traces of animals, plants and other organisms from the past. Organisms are only rarely preserved as fossils, and only a fraction of these fossils have been discovered. The number of species known through the fossil record is less than 5% of the number of known living species. A condition that would favour the fossilisation of an organism is A. possession of soft body parts which are easily compressed under sediment. B. possession of hard body parts. C. slow burial, which reduces damage to remains. D. an environment with strong winds or water current. 18

21 EVIDENCE FOR EVOLUTION Q4 Outline the evidence for evolution provided by homologous structures. [6] 19

22 NATURAL SELECTION Q1 Charles Darwin and Alfred Wallace proposed a theory of evolution in the late 1850s. One observation made by Darwin that helped formulate the theory was: A. the environment remaining constant during the lifetime of an organism. B. individual organisms losing a trait that was not in use. C. individual organisms evolving in their own lifetime. D. inherited variation existing within a population Q2 Since the introduction of the poisonous cane toad to Australia in 1935, there has been an increase in the ratio of body length to head size in two species of snakes, the Red-bellied Black Snake and the Green Tree Snake. A smaller headed snake cannot consume a large prey item, and so cannot swallow a large cane toad that has sufficient toxin to kill the snake. The rapid evolution of body dimensions in the Red-bellied Black Snake and the Green Tree Snake most likely came about because A. cane toad toxin reduced the head size of the snakes. B. even small cane toads contain enough toxin to kill a long-bodied snake. C. smaller headed snakes are better at catching cane toads than large headed snakes. D. larger headed snakes were killed by the levels of toxin ingested when they ate a large cane toad Q3 Explain how natural selection can lead to evolution using antibiotic resistance in bacteria as an example. [9] 20

23 NATURAL SELECTION 21

24 CLASSIFICATION Q1 Ranunculus repens and Hypericum repens both have yellow flowers. Which statement is true? A. They are angiospermophytes. B. They are coniferophytes. C. They are members of the same species. D. They are members of the same genus. Q2 What distinguishes Annelida from Platyhelminthes? A. Platyhelminthes have a segmented body but Annelida do not. B. Platyhelminthes reproduce sexually but Annelida do not. C. Platyhelminthes have radial symmetry but Annelida have bilateral symmetry. D. Annelida have both a mouth and an anus but Platyhelminthes do not. Q3 State an external feature that is different in: c. Cnidaria and Mollusca. [1] d. Mollusca and Annelida. [1] Q4 a. Define the term species. [2] b. List three domains into which living organisms are classified. [1] c. There are seven levels used in the hierarchy of taxa. State which two are used in the binomial system of nomenclature. [1] 22

25 CLADISTICS Q1 a. Outline the evidence provided by DNA for the common ancestry of living organisms. [2] b. The cladogram below shows the classification of species A to D. Deduce how similar species A is to species B, C and D. [2] c. Suggest two reasons for using cladograms for the classification of organisms. [2] 23

26 CLADISTICS Q2 It has been suggested that elephant-like ancestors of the woolly mammoth left Africa 3.5 million years ago (mya) and lived in Central Europe. The chart below shows a summarised phylogenetic tree based on mitochondrial and chromosomal DNA from fossils and living elephants. a. Explain how the woolly mammoth M. primigenius probably arose from the woolly mammoth ancestor M. africanavus. [3] b. Suggest how it could be possible for M. primigenius to have arisen so recently (0.2 mya) yet now be extinct, while the Asiatic elephant, E. maximus, has been present for over 6 million years. [2]... 24