5-6: Evidence of Evolution

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Evidence of Evolution & The Fossil Record

Multiple Choice

True or false: Darwin made his observations on the Galapagos Islands

• True

• False

Multiple Choice

Members of a species can mate with each other and produce...

• Gene Pools

• Fertile Offspring

• Variation

• Adaptations

Multiple Select

Select all aspects of Natural Selection

• Variation

• Selection

• Overproduction

• Competition

• Restriction

Multiple Choice

Bird beaks having different shapes is an example of a(n)

• Fossils

• Adaptation

• Habitat

• Naturalism

Lesson Objectives

• List and provide examples of the main kinds of Evidence that support the Theory of Evolution

• Describe how Fossils form

  • Differentiate between different kinds of fossils

• Discuss what Fossils tell us about organisms and environments of the past and support the theory of evolution

Evolution as A Scientific Theory

• Evolution is considered to be a scientific theory

  • Recall: A theory is a collection of well-tested and consistent hypotheses

• There are multiple different ways the theory of evolution is supported

  • 8 broad categories

Observations of Natural Selection in Action

• We can observe how a species changes over time, and see natural selection as it occurs

  • Recall: our Australian Rabbits evolved to resist a natural virus

• Bacteria provide the fastest way to see selection pressures

  • Antibiotic Resistance can be "selected for" in a population and become the most frequent trait

Artificial Selection

• Artificial Selection: The selective breeding of organisms with desirable traits to obtain desirable traits

  • Humans put selective pressure on a population rather than nature

• This can result in drastic changes

• Examples:

  • Agricultural Breeds

  • Dogs

Darwin's Pigeons

• When he returned to England, Darwin looked to support his theory by studying domesticated animals

• Darwin bred pigeons to have fan-shaped tails

  • Only would breed individuals with the shape he wanted

    • Some additional characteristics would still be passed on, like the number of feathers

• Over time, all the pigeons born from his breeding had more feathers than those he let breed normally

Similarities in Body Structure

• When we Observe the body structures of different organisms we see a lot of repeating patterns

  • Example: Arms in mammals follow a one-bone, two-bone, many bones, finger pattern

• If all these organisms had originated independently, the bone structures would be more specialized to the function of the limb

  • It instead seems the structure was inherited from a common ancestor

Homologous Structures

• Homologous structures: Similar structures that related species have inherited from a common ancestor

  • Fossils are the main way of identifying homologous structures

    • Looking at extinct species can help show where a trait first appeared

Vestigial Organs

• Vestigial Organs: Organs in an organism that are not functional, but remain from a previous ancestor

• Examples

  • Snakes have very tiny incomplete leg bones

  • Many species that live in dark caves still have eyes, even though they cannot see

  • Humans have a coccyx (tail bone) that remains from ancestors with tails

DNA & Molecular Evidence

• Closely related species have similar DNA Nucleotides

  • The more closely related, the more nucleotides in common

• Noncoding regions are also common, which indicates that they would come from a shared ancestor

  • Noncoding regions are not selected for, and it is unlikely so many species would randomly develop the exact same ones without a common ancestor

Multiple Choice

Which of the species listed is the most distantly related to the horse?

• Donkey

• Rabbit

• Snake

• Turtle

Multiple Choice

Scientists infer that species with similar body structures and development patterns had a common

• Environment

• Predator

• Ancestor

• Gene

Multiple Choice

Only organisms with a desired characteristic are bred by people in

• Artificial Selection

• Natural Selection

• England

• South America

• The Galapagos

Patterns of Development

• Related Species go through many of the same developmental stages

  • All animals start as a single cell organism

  • The Earliest stages of development look very similar for most organisms

    • Have a tail

    • Have gill slits near the throat

• These indicate that we all started from the same common ancestor and are related

Hierarchical Organization of Living Things

• When we look at different organisms, we can put them into groups

  • Example: Vertebrates have a backbone

• We can then further divide groups into smaller groups that share specific adaptations

• The more closely related species are, the more traits they have in common

Biogeography

• Biogeography: The study of how species are distributed on Earth

• Biogeography tends to be consistent with evolution

  • Organisms evolved in a certain place and left descendants in places where they were

  • Not all locations with the same habitat types have the same organisms

Multiple Choice

Scientists infer evolutionary relationships by comparing the early development of different

• dinosaurs

• backbones

• proteins

• organisms

Multiple Choice

Structures with the same parts have different functions; suggests that organisms share a common ancestry

• vestigial structures
• homologous structures
• adaptive radiation
• fossil

Multiple Choice

Study of embryos of various organisms to show a common ancestor because of similarities in development

• natural selection
• embryology
• speciation
• evolution

Multiple Choice

The diagram illustrates an embryonic stage of two organisms.

Which of the following can be determined by observing the embryos shown in the diagram

• The organisms share a common ancestry.
• The organisms belong to the same genus.
• The organisms are native to the same geographic areas.
• The organisms will grow into anatomically similar adults.

​What are Fossils?

• Fossil: the preserved remains or traces of living things

  • Includes things like:

    • Bones

    • Teeth

    • Imprints

  ​

​How do Fossils Form?

• Most Fossils form when living things die and are buried by sediment

• Are found in or near still water where sediment builds up

  • After an organism dies, the soft tissue decays quickly or gets eaten

    • ​Usually only hard tissues remains

  • Over time, sediment covers the organism in layers and hardens into rock

​What are the different kinds of Fossils?

• ​Different kinds of of fossils include

  • Molds and Casts

  • Petrified Fossils

  • Carbon Films

  • Trace Fossils

  • Preserved Remains​

​Molds & Casts

• The most common types of fossils

  • Preserve the fine details of the organisms (Textures, shapes)

• Mold: a hollow area in sediment in the shape of an organism

  • Forms when the organism is buried in sediment

  • Just an imprint

• Cast: A solid copy of the shape of an organism​ where sediment fills in spaces

  • Shows all the fine details

​Petrified Fossils

• Petrified: turned to stone

• In petrified fossils, minerals replace all or part of an organism

  • water seeps into the cells, carrying minerals

  • Eventually water evaporates and the minerals are left behind, taking the form of the organism

• Are usually plants or bones​

​Carbon Films

• An extremely thin layer of carbon is left behind of an organism

• While other sediment is removed, the carbon leaves a flat image behind

• Preserves the most delicate details of organisms

  • Shows the outer details of an organism

​Trace Fossils

• Show activities of an organism

  • Foot prints

  • Nests

  • Scat

• Can reveal what an organism did and ate

​Preserved Remains

• Preserve the entire organism

  • Freezin​g in ice

  • Trapped in amber

    • Amber: Hardened tree sap

  • Tar Pits

​Answering The Jurassic Park Question

• It isn't possible to retrieve DNA from remains in Amber

  • While some tissue remains, the DNA degrades over time

• Frozen Fossils do preserve some DNA, but it is extremely difficult to extract

  • DNA degrades as the fossil thaws

    • Wooly Mammoth DNA has been preserved

  • 2021:​ Scientists believe they may have successfully retrieved DNA from a frozen dinosaur

    • tests remain inconclusive as to whether it is true Dinosaur DNA

Multiple Choice

A __________ fossil can form when sediment buries the hard tissues of an organism.

• mold/cast

• Trace

• Carbon Film

• Petrified

Multiple Choice

A __________ fossil forms when minerals replace parts of an organism

• mold/cast

• Trace

• Carbon Film

• Petrified

Multiple Choice

Which of the following can you learn from a carbon film fossil?

• How an organism behaved

• What an organism ate

• Fine Details of an organisms body

• The bone structure of an organism

Multiple Choice

Which of the following substances is not able to preserve entire organisms?

• Tar

• Water

• Amber

• Ice

​What do Fossils show?

• Paleontologists: Scientists who study fossils

• Paleontologists gather information into the Fossil Record

  • Provides evidence about the history of life and past environments on Earth

    • Helps show how organisms have changed over time

​Fossils and Past Environments

• The types of fossils found in an area can tell what the area was like in the past

  • Can tell if a location was under water or on land

    • Can distinguish between fresh and salt water

  • Can show the previous climates of area

    • Antartica has coal deposits, which only form in warm climate

​Change and the Fossil Record

• Looking through the fossil record, changes in species can be seen

  • Organisms become more complicated in subsequent generations

  • Older rocks have simpler organisms, while newer rock has more complex organisms

• Extinct: a type of organism no longer ​exists and will no longer reproduce on Earth

  • This can occur due to different factors like environmental changes

  • Fossils help scientists construct models of what extinct organisms could have looked like

Multiple Choice

How do fossils provide evidence that evolution has happened on Earth?

• Fossils show how the sizes of certain animals has changed drastically over millions of years
• Fossils show that some species have gone extinct
• Fossils show how life forms present today are different than those from the past
• Different sedimentary rock layers provide evidence for how the environment has changed over time

Multiple Choice

This is the sort of scientist who studies fossils/

• Geologist

• Evolutionist

• Paleontologist

• Fossilist

Multiple Choice

_____________ is the gradual change in living things over long periods

• Evolution

• Petrification

• Fossilization

• Paleontology