8.L.4.1 Evolution & Genetics

8.L.4 Evolution & Genetics

Focus Standard 8.L.4.1

Theory of Evolution

What evidence do scientists have to prove the theory of evolution?

Learning Targets

• Examine the evidence that scientists used to prove the theory of evolution.

• Summarize the theory of evolution and what evidence is used to help prove this.

Evolution

• Since genes control traits and we know that traits can be inherited. What determines which traits are seen most often in a population of organisms?

• Did you know that the male red deer needs big antlers in order to attract a mate? The male deers with big antlers are more desirable to females so they are chosen more often.

• This process is known as evolution.

Multiple Choice

Genes control traits and traits are inherited. This means that they are pass from their parent to the offspring.

• True

• False

Evolution

• Applies to a population, a group of the same species that live in area, rather than just an individual organism. The whole group!

• Species is group of organims that can mate and produce offspring that can mate.

• Evolutionary changes happen at the genetic level. Organism genes change in different ways during reproduction which create new and improved traits.

• Occurs over many, many generations.

• 
  

Multiple Choice

Evolution is the process of ________ over _______.

• time over change

• change over time

• traits over genes.

• none of the above.

Multiple Choice

A population is a

• an individual organism living in the same area.

• a group of the same species living in the same area.

• A community of organisms that live in different areas.

Multiple Choice

____________ ______________ happen at the genetic level. Organism genes change in different ways during reproduction which create new and improved traits.

• Genetic changes

• Evolutionaary changes

• Population changes

• Species changes

Similar Species

• Charles Darwin was the father of the Theory of Evolution.

• He took a voyage to several islands when he was around 20 years old. On his voyage he visited the Galapagos Islands. They are located off the current coast of Ecuador. where he discovered a species of birds...Finches.

• He noticed that the Finches on each of the Islands were different from each other and different from those on the mainland.

Finches on Galapagos Islands

• Because Darwin drew each of these by hand and in grave detail he noticed that each of the Finches beaks were very different.

• Some birds had strong wide beaks, while others had narrow needle like beaks.

• He determined that the shape of the beak determines what kind of food they could eat.

• We will see this in the next slide.

Finches Continued

• The finches with the strong wide beaks eat seeds because their beaks were perfect for cracking open the seeds.

• The birds with the narrow needle like beaks eat insects because their beaks were perfect for getting into places where insects lived.

• So since each Finch reproduced in isolation from each other in Theory. Different traits evolved that were suited for the conditions of a specific island. Thus this is why Finches on different islands had different beaks.

Multiple Choice

Darwin observed different species of an animal on separate Galapagos Islands. Which animal did he observe?

• horse

• zebra

• finch

• elephant

Open Ended

Which trait was different among the species of that animal?

EVIDENCE #2-Fossils

Most of the evidence of Evolution was originally found as fossils.

Fossils can preserve the structures of an organism in many ways. They give us a good idea of what certain organisms looked like throughout Earth's long history. The fossil record is not complete.

Examples include: Bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, petrified wood, oil, coal, and DNA remnants.

Open Ended

What is the importance of fossils when learning about the past?

Evidence #3-SImilar DNA

Scientists compare the DNA of different species in order to find similarities.

DNA similarities can tell us about common ancestry.

DNA analysis has allowed us to understand evolution better and forced us to reclassify species as more or less related than we originally thought.

Our DNA is very similar of that in Chimpanzees but WE DID NOT COME FROM MONKEYS.

Evidence #4-Structural Clues (Comparative Anatomy)

• Embryonic Similarities

• Homologous & Analagous Structures

• Vestigial Structures

Ebmryonic Similarities

Embryology is the study of embryos. Comparing the development of multiple species embryos helps us understand that many species share characteristics in their early development.

Example: all of these have musles arranged in groups or bundles and a tail. They also have a hard protective covering over the brain.

Homologous Structures

• Many species living today have similar body structures.

• Examples of Homologous Structures: Human arms, bird wings, whale flippers, dog forearms, and frog forelimbs.

• These structures support the idea that the different animals descend from a common ancestor and serve as evidence of evolution.

Analogous Structures

• Analogous structures are similar structures that evolved independently in two living organisms to serve the same purpose.

• The term “analogous structures” comes from the root word “analogy,” which is a device in the English language where two different things are based on their similarities.

• The structures are not the same, and were not inherited from the same ancestor. But they look similar and serve a similar purpose.

Vestigial Structures

• Vestigial structures are evolutionary leftovers.

• They are structures that have no function in an organism, but they come from a common ancestor that did need that structure. Over time, evolution and adaptation eliminated the need for these structures, yet they remain.

• Humans have many examples of vestigial structures in their bodies. The tailbone is one body part that does not serve a function anymore. It starts as a tail and then the vertebrae fuses into tailbone.

Multiple Select

What do scientists use to help prove the theory of evolution? Check all that apply.

• Fossils

• Similar DNA

• Embryology

• Similar Species

• Homologous & Analogous Structures

Multiple Select

Which of the following involves evolution? (check all that apply)

• Tadpole turning into a frog.

• A seed growing into a tree.

• Darwin's Finches that had different beaks.

• Similar DNA with humans and chimpanzees.

• Caterpillar turning into a butterlfy.

Open Ended

Put the steps of evolution by natural selection in order. You just need to type the number in order.

Multiple Select

Check all conditions that can affect the rate of evolution:

• Type of reproduction and reproduction rate.

• Gestation period

• Environmental changes

• Number of offspring

• Rate of mutation

Open Ended

Rank the order for the Rate of Evolution: Which one was the fastest, 2nd fastest, and last between the bacteria, cats, and human?

Open Ended

Name some species you know are extinct!

Multiple Choice

What does it mean to be an endangered species?

• no member of species is left

• a very few amount of the species is left

• The species is in danger of becoming extinct.

• b and c are both correct

Open Ended

Can you name an endangered species?