SB5C. Explain how fossil and biochemical evidence support the theory Evidence of Evolution (15.2) State Standard SB5C. Explain how fossil and biochemical evidence support the theory

Chapter 15 Evolution 15.2 Evidence of Evolution The Fossil Record Fossils provide a ____________ record of species that lived long ago. Only the ____________ parts of an organism are likely to leave fossils – ex: shells, bones, thick cell walls. Very few fossils capture the details of ____________ or internal ____________. Sometimes ____________ are left behind in sediments along rivers and lakes.

The Fossil Record cont’d Chapter 15 Evolution 15.2 Evidence of Evolution The Fossil Record cont’d Fossils show that ancient species share ____________ with species that now live on Earth. One problem w/ the fossil record is the lack of any “____________” or transition forms. This could be due to many organisms being too ____________ or due to fossils being ____________ by the erosion or pressure. Glyptodont Armadillo

Determining Fossil Age Chapter 15 Evolution 15.2 Evidence of Evolution Determining Fossil Age Biologists use ____________ dating to determine the approximate age of fossils. The isotopes act as ____________ for measuring time. To use this method, scientists must know: 1. The ____________ of the isotope being measured. 2. how much of the isotope was ____________ present in the fossil or in the rock containing the fossil. 3. how much of the isotope is ____________.. Half-life is the amount of time it takes for half of the isotope to ____________.

Determining Fossil Age Cont’d Chapter 15 Evolution 15.2 Evidence of Evolution Determining Fossil Age Cont’d Biologists most often use ____________ for radioisotope dating, but its half-life is relatively ____________. Other isotopes like Uraniaum 235 are often used to help determine the age of older fossils. Relative dating determines the relative age of rocks/fossils by ____________ them to known older or younger layers.

Comparative Biochemistry Chapter 15 Evolution 15.2 Evidence of Evolution Comparative Biochemistry Common ancestry can be seen in the complex metabolic ____________ that many different organisms share.

Chapter 15 Evolution 15.2 Evidence of Evolution Comparative Biochemistry Cont’d Comparisons of the similarities in these molecules across species reflect evolutionary ____________ seen in comparative anatomy and in the fossil record. Organisms with closely related ____________ features have more closely related ____________ features.

Chapter 15 Evolution 15.2 Evidence of Evolution Comparative Embryology Vertebrate ____________ exhibit homologous structures during certain phases of development but become totally ____________ structures in the adult forms. Many scientists believe this is evidence that all vertebrates ____________ a common ____________.

Homologous Structures Chapter 15 Evolution Anatomical Evidence Homologous Structures ____________ similar structures that may or may not have the same ____________. Indicate possible ____________ ancestry

Chapter 15 Evolution Anatomical Evidence Analogous Structures Similar in function but __________ in __________ so they do not indicate shared ancestry Show that functionally similar features can evolve independently in __________ environments

predicts that features of ancestors that no Chapter 15 Evolution Anatomical Evidence Vestigial Structures Structures that are the ____________ forms of functional structures in other organisms. Evolutionary theory predicts that features of ancestors that no longer have a function for that species will become ____________ over time until they are lost.

Chapter 15 Evolution Anatomical Evidence Adaptations An adaptation is an ____________ trait that may increase an organism’s survival and reproductive success. ____________ is a measure of the relative contribution an individual trait makes to the next generation.

Allows organisms to become almost ____________ to predators Chapter 15 Evolution Anatomical Evidence Adaptations Cont’d Camouflage Allows organisms to become almost ____________ to predators All about ____________ Leafy sea dragon

One species evolves to ____________ another species. Chapter 15 Evolution Anatomical Evidence Adaptations Cont’d Mimicry One species evolves to ____________ another species. All about ____________/warning (not hiding). Western coral snake California kingsnake

Chapter 15 Evolution 15.2 Evidence of Evolution Geographic Distribution The distribution of plants and animals that Darwin saw first suggested evolution to Darwin. Rabbit Mara

Chapter 15 Evolution 15.2 Evidence of Evolution Geographic Distribution Cont’d The Mara & Rabbit fill the same ____________ on 2 different continents. Darwin observed that the Mara was more ____________ to other South American species than it was to the rabbit, and vice versa. Mara Rabbit

Chapter 15 Evolution 15.2 Evidence of Evolution A ____________ is a description of the line of descent of a group of organisms. Fossil collections are often not ____________ enough to determine any evolutionary patterns or traits, so biologists will ____________ likely phylogenies by comparing morphological features, DNA sequences, and chromosomal characteristics. ____________ is the permanent loss of a species. Phylogenetic Trees

Chapter 15 Evolution 15.2 Evidence of Evolution Types of Characters (traits) ____________ traits are newly evolved features, such as feathers, that do not appear in the fossils of common ancestors. ____________ traits are more primitive features, such as teeth and tails, that do appear in ancestral forms. Anatomically similar structures inherited from a common ancestor are called ____________ structures.

Cladogram - a diagram showing possible relationships between organisms based on shared traits (characters)

How to Read – if the organism is above the trait, it has the trait How to Read – if the organism is above the trait, it has the trait. If it is below the trait, it doesn’t have it.

Ancestral Character – shared by all species on the diagram. Derived Character- only shared by some Outgroup – least in common

Homologous or Analogous? Bat Wing Human Arm

Homologous or Analogous? Bat Wing Bird Wing

Homologous or Analogous? Dragonfly Wing Hummingbird Wing

Homologous or Analogous? Dragonfly Wing Bumblebee Wing