EVIDENCE FOR LIVING THINGS CHANGING ACROSS TIME

Four Scientific Fields that Study Evidence of Change

Paleontology

Physical Anthropology

Developmental Biology

Evolutionary Biology

Physical Anthropology Physical Anthropologists are scientists who

study how humans and their ancestors have changed biologically over time.

Physical Anthropology

Physical Anthropology Similarities in skull structure offers

evidence of common ancestry. Changes in skull structure indicate

change across time.

Paleontology The study of prehistoric life and

evolutionary relationships through the fossil record.

Paleontology Evidence for Change through the fossil

record

Fossils Found in Strata

Paleontology Evidence for change across time

Fossil record shows gradual change over time of a large number of species

Higher Rock levels Younger Fossils found here. Fossils are similar to modern species

Lower Rock levels Older fossils found Fossils are much different from modern species

Developmental Biologist Scientists who study the stages of growth

and development that living organisms pass through as they grow from fertilized egg to mature adult.

Developmental Biologist Embryology- Branch of developmental

biology that focuses on the early development of organisms before they are born or hatched.

Embryo- Developing organisms during the prebirth/prehatch stage.

Evidence of ChangeSimilarity of early stages of development indicate common ancestor

Evidence of ChangeThe more similar the later stages of

embryos look alike, the closer the relation

Evidence for change The presence of DNA in ALL living

organisms is evidence that all living things evolved from a common ancestor.

Evidence of changeThe similarity of DNA sequencing is evidence of that

these organisms share common ancestors.

Animal Percentage of DNA that is the same as human DNA

Fruit Fly 60%

Chicken 60%

Domestic cat 90%

Monkey (an old world primate) 93%

Gibbon (a lesser ape) 95%

Chimpanzee (a great ape) 98%

Our Closest Relation The Bonobo’s and Chimpanzee’s DNA

sequencing is 98% the same as Human DNA sequencing.

This is strong evidence that humans, chimpanzees and Bonobos share a common ancestor.

Evolutionary BiologyEvolutionary Biologists are scientists who

study how living organisms change physically over time.

Charles Darwin wrote “TheOrigin of Species”

Evolution through Natural Selection

Evolutionary Biologists Homologous Structures- Characteristics

that are similar among different organisms because they evolved from a common ancestor.

Vestigial Structures- Structures that seemingly serve no purpose in some animals that are functional in other animals.

Homologous Structures•Evidence for common ancestor•Structures evolved and changed across time

Vestigial Structures Shows Evidence of change over time as

structures that no longer serve a purpose are still present.

Vestigial StructuresThe Pelvic Girdle was functional in the ancestors of the modern Whale.

The structure no longer serves a purpose but is still present

Human Vestigial Structures