Evidence of Evolution Main Types of Evidence 1. Fossils 2. Homologous structures 3. Embryology.
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Transcript of Evidence of Evolution Main Types of Evidence 1. Fossils 2. Homologous structures 3. Embryology.
Evidence of Evidence of Evolution Evolution
Main Types of Main Types of EvidenceEvidence
1. Fossils
2. Homologous structures
3. Embryology
Fossil recordFossil record• Layers of rock contain fossils
onew layers cover older ones• creates a record over time
o fossils show a series of organisms have lived on Earth • over a long period of time
Fossils tell a story…Fossils tell a story…
the Earth is oldthe Earth is old
Life is oldLife is old
Life on Earth has changedLife on Earth has changed
Fossil RecordFossil Record• Fossils are evolutionary evidence
• Fossils show that ancient species share similarities with species that now live on Earth.
• Fossils records provide evidence that living things have changed over time.
Glyptodont Armadillo
Comparing AnatomyComparing Anatomy• Homologous structures
• Analogous structures
• Vestigial structures
Compare the bonesCompare the bones
• The same bones under the skino limbs that perform different functions are built from the same
bones
How could thesevery different animalshave the same bones?
Homologous Homologous structures structures
• Structures that come from the same origin• homo- = same• -logous = information
• Anatomically similar structures inherited from a common ancestor
• These structures can be similar in arrangement and/or function.
Homologous Homologous structuresstructures
• Forelimbs of human, cats, whales, & bats o same structure
• on the insideo same development in embryo o different functions
• on the outsideo evidence of common ancestor
Analogous Structures Analogous Structures • Structures that do not have a common
evolutionary origin but are similar in structure.
• Shows that functionally similar features can evolve independently of each other
• Ex: wing of an insect and wing of bird
Analogous Structures Analogous Structures
Vestigial Structures Vestigial Structures • A body structure that has no function in a
present-day organism but was probably useful to an ancestor.
• This shows a change over time
• Hind leg bones on whale fossils
Why would whales have pelvis & leg bones if they were always sea creatures?
Why would whales have pelvis & leg bones if they were always sea creatures?
Because they used to walk on land!
EvolutionChapter 15
Comparing Embryos Comparing Embryos • Embryo: the earliest
stage of growth and development of both plants and animals
• Vertebrate embryos exhibit homologous structures during certain phases of development but become totally different structures in the adult forms.
Comparing EmbryosComparing Embryos• Similar embryo development may suggest a
common ancestor
Biochemical Evidence Biochemical Evidence • Common ancestry
can be seen in the complex metabolic molecules that many different organisms share.
• Comparison of the DNA or RNA of different species produce biochemical evidence for evolution
Biochemical Evidence Biochemical Evidence • Comparisons of the similarities in amino acids
and other molecules across species reflect evolutionary patterns seen in comparative anatomy and in the fossil record.
Knowledge CheckKnowledge Check
True or False
Organisms with similar anatomy share
similar DNA sequences.
Knowledge Check Knowledge Check Which of the following best explains how the fossil record provides evidence that evolution has occurred?
A It indicates the exact cause of structural and behavioral adaptations of organisms.
B It shows that the form and structure of groups of organisms have changed over time.
C It shows how the embryos of many different vertebrate species are very similar.
D It indicates that forms of life existed on Earth at least 3.5 billion years ago.
Knowledge CheckKnowledge CheckThe occurrence of the same blood protein in a group of species provides evidence that these species
a. evolved in the same habitat.
b. evolved in different habitats.
c. descended from a common ancestor.
d. descended from different ancestors.