Biology Unit 9 - Evolution

the process of change which causes offspring (descendants) to differ from their ancestors

Evolution

what explains how new species form?

evolution

a group of organisms that can reproduce and have fertile offspring

Species

In 1809, Jean-Baptiste LaMarck started to think about evolution. What did he say?

he said fossils of extinct animals resemble animals living today

What is LaMarcks’s theory called? What does it mean?

• The Theory of Acquired Characteristics

• This means that traits that are acquired during your lifetime are passed onto future generations

According to this theory, all giraffes once had short necks. They had to stretch their necks to reach high branches. What are the two major problems with this theory?

• Can’t stretch organs

• Can’t pass on acquired traits

Scientists study ______ to learn more about how evolution works.

Fossils

hard parts of animals that lived in the past

Fossils

What body parts would make the best fossils?

• bones

• Claws

• Teeth

What are the two ways that evolution may happen?

1. Catastrophism (catastrophes)

2. Gradualism (gradually)

What are examples of catastrophism (catastrophes)?

Natural disasters:

• floods and volcanoes

• happen that cause entire species to go extinct

What is gradualism (gradually)?

Slow processes that cause organisms to evolve over a long period of time

In 1831 Charles Darwin traveled on a ship called ___ ______ for an around the world journey. He stopped in the _________ _______ for observations.

HMS Beagle

Galapagos Islands

What did Darwin notice on the islands?

• All of these animals that were never seen anywhere before

• variation

differences between members of a population

variation

Variation includes physical differences (____,____) and non-physical differences (_____ _____, ______ __ _______)

• color and size

• foods eaten, number of offspring

Darwin said these ______ allow them to survive in a changing environment.

Adaptions

Wheee do we see more variation?

Domesticated animals (pets) or wild animals?

Domesticated animals (pets)

humans choose what traits we want our pets to have and breed accordingly

artificial selection

must be able to passed on

heritable

T or F

In nature, the environment determines which traits are favorable - not humans

True

Who created The Theory of Natural Selection?

Charles Darwin

individuals that have beneficial adaptations are more likely to mate and pass on those traits

Natural selection

Darwin argued that there are not enough resources for every organism in a ______. The ones that have the _______ adaptations will survive, and then pass them on.

• Population

• Favorable

How many parts are there to the theory of natural selection?

4

What are the first two parts to the theory of natural selection?

1. There is variation (differences) in every population

2. Some of this variation is good and some is bad

What are the 3rd and 4th parts to the theory of natural population?

3. Not all young produced in each generation will survive

   • many will die as a result of disease, starvation, or predators

4. Individuals that survive and reproduce are those with the favorable variations

being able to better survive and reproduce than other members of their population

Fitness

the study of fossils or extinct organisms

paleontology

someone who studies fossils

paleontologist

Fossils of fish have been found in places where no water exists today - this is evidence of what?

Pangea

What is a difference and more evidence of Pangea between African and Asian elephants?

Found on different continents

the study of how living things are distributed around the world

Biogeography

the study of embryos (unborn babies) and how they form

embryology

the body structure of a living thing

anatomy

What two themes of anatomy did Darwin notice?

Homologous and analogous

structures that are SAME in structure but different species and have different functions and form the SAME ancestors

• evidence that they all evolved from a common ancestor

Homologous structures

similar functions, but mot similar in origin

Analogous structures

inherited structures that are reduced in size and unused

Vestigial structures

Why is genetic variation very important in population?

The more variation in a population, the better the population’s chances for survival

Which penguin would do better if it’s a brutal cold winter?

Short, fat penguins stay warmer

combines alleles of all the individuals in a population and stores genetic variation

gene pool

is the measure of how common an allele is in a population

allele frequency

random change in the DNA

mutation

different ways mom’s and dad’s chromosomes can match up

recombination

In a population, traits are usually arranged by a what?

Normal distribution

means most fall in the middle

• sometimes called a bell-shaped curve

Normal distribution

How many ways are there that distribution can change?

Three

favors phenotypes at an entrance

Ex – peppered moths

•Before the industrial revolution, moths appear lighter in

color

•Tree trunks darkened with pollution and light colored

moths were picked off by birds

•Darker color moths became the new “norm”

directional selection

the middle is favored, the extremes are bad (reduced)

Ex- Birth weight in babies

● If the birth weight of a baby is too low, it will have difficulty

surviving after birth.

● A baby weighing too much would create complications for both

the mother and the child.

● The middle ranges are the optimal birth rate.

stabilizing selection

both extremes are favored, the middle is selected against

Ex – Lazuli birds

•Range in color from dull brown to bright blue

•Bright blue – most aggressive, mate often

•Dull brown – not seen as a threat, left alone, mate

often

• Middle colors – selected against

Disruptive selection

A difference in the physical traits of one individual from another in the same group

Variation

The fact that saddle-back tortoises have evolved abnormally long necks is an example of:

Adaptation

While on the ship Darwin:

Found evidence for natural selection

The change in allele frequencies over time.

Evolution

Which of the following ideas proposed by Lamarck was later found to be incorrect?

Acquired characteristics can be inherited

Which of the following ideas is supported by Darwin’s observation of local variation among tortoises in the Galápagos Islands?

a. artificial selection

b. adaptation

c. acquired characteristics

d. tendency towards perfection

Adaptation

The ability of an organism to survive and reproduce in its specific environment.

Fitness

Natural selection is ______________

Survival of the fittest

Remains of ancient organisms are called _________

Fossils

How does embryology support the Theory of Evolution?

a. It shows that embryos who develop similarly share a

common ancestor

b. It shows that embryos who develop similarly are not

related to one another

c. It shows that organisms have the ability to evolve, or

change, over time.

a. it shows that embryos who develop similarly share a common ancestor

Some organisms that share a common ancestor have features that have different functions, but similar structures. These are known as:

Analogous structures

The similarities of the bones in the diagram provide evidence that---

The organisms shown may have developed from a common ancestor

The study of embryos (unborn babies) and how they form

Embryology

A group of organisms that can reproduce and have fertile offspring

Species

Any trait that is able to be passed on

Heritable

body structure of a living thing

Anatomy

Humans choose what traits we want our pets to have and breed accordingly

Artificial selection

The study of how living things are distributed around the world

Biogeography

Differences between members of a population

Variation

The process of change which causes offspring (descendants) to differ from their ancestors

Evolution

Inherited structures that are reduced in size and unused (appendix)

Vestigial structures

Theory that says that traits that are acquired during your lifetime are passed on to future generations

Theory if Acquired Characteristics

Slow processes that cause organisms to evolve over a very long period of time

Gradualism

The study of fossils or extinct organisms

Paleontology

Theory that says that Individuals that have the beneficial adaptations are more likely to mate and pass on those traits

Theory of Natural Selection

Structures that are similar in structure but in different species and have different functions (cat and human arm)

Homologous structures

Natural disasters – floods, volcanoes – happen that cause entire species to go extinct

Catastrophism

Structures that are similar function, but not similar in origin (whale and shark fins)

Analogous structures

Someone who studies fossils

Paleontologist

The different ways mom’s and dad’s chromosomes can match up are known as _______________ .

Recombination

SELECT ALL THAT APPLY: Which of the following must be true in order

for organisms to be considered the same species?

a. They must be able to mate

b. They must be able to produce viable offspring

c. They must have structural similarities

d. They must have the same bone structure

b. They must be able to produce viable offspring

c. They must have structural similarities

This distribution graph shows

Stabilizing selection

What does the 'p' value represent in the Hardy-Weinberg equation?

a. Probability of homozygous recessive genotype

b. Probability of heterozygous genotype

c. Frequency of the dominant allele

d. Frequency of the recessive allele

c. Frequency of the dominant allele

How do you calculate the frequency of heterozygous individuals in a population?

2pq

If 16% of a population is unable to taste a certain chemical due to a recessive allele, what is the frequency of the recessive allele (q)?

0.4

What is the significance of the Hardy-Weinberg equilibrium in studying genetic disorders?

a. It helps in understanding the spread of disorders

b. It predicts the future genetic makeup of populations

c. All of the above

d. It assists in calculating carrier probabilities

c. All of the above

In the Hardy-Weinberg Equation, q2 is the frequency of what?

The dominant genotype

2. A population of 150 individuals has an allele frequency of 0.4 for the dominant allele (B) and a frequency of 0.6 for the recessive allele (b). Use the Hardy-Weinberg equation to determine the frequency of the genotype (bb).

a. 0.09

b. 0.42

c. 0.36

d. 0.72

c. 0.36

Which of the following conditions is necessary for a population to be in Hardy-Weinberg equilibrium?

Large population size