Evolution Activities

1.1 Biological evolution1.2 The theory of recapitulation1.3 Radiometric dating

2.The THEORY OF EVOLUTION includes the following:All present day life forms descended from and are related to

those that lived in the past.Present day life forms may look different from those of the past

as they have become modified from one generation to the next.

Activity 1

Homologous StructureSimilar structures in various organisms that are due to a common

ancestor. They may be used for different purposes e.g. The forearm of a lizard (walking), dolphin (swimming) and a bat (flying) have the same

anatomy but are use for different forms of locomotion.

Analogous StructureOrganisms have similar structures but there is no common ancestor. These structures have similar characteristics that perform the similar functions, e.g. spines on an Echidna and cactus.

lizard dolphin bat

4. Ideas from fossil record

Earth is 4.5 billion years old.First life forms 3.8 million years ago.Today’s life forms are more complex.

Many life forms are extinct.Fossils show gradual increase in size to present day forms.

5.• Biochemical molecules DNA, ATP

• Gene similarities. Some portions of DNA with no function.• DNA triplet code the same in protein synthesis.

• Same 20 amino acids• Cellular respiration pathways are the same

Activity 2

1. The original finch population had flown in from South America’s mainland. There were no natural predators for these birds and their numbers increased.

This lead to competition amongst the birds.2. There was no competition so the numbers of birds increased. More birds lead to competition for food.3. To the forest.4. Moved to the thicker forest that was inland.5. Less competition

6.The birds in the forest only mated with those that lived in the forest.

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• Within a large population there was variation• Some birds had large beaks some shorter ones. Then

there was a selection pressure. Those with short beaks mover to an area where the food was plentiful.

• The populations separate.• Those which are adapted to the new environment

survive and pass these genes on to future generations.

The Law of Use and Disuse

If organs were used they would increase in size or efficiency.

If organs were not used they would get smaller and disappear.

Eyes of moles have stopped functioning because of disuse.

Legs of snakes have been reduced due to disuse.

Webbed feet in birds are the result of spreading the toe bones and the skin between them in order to swim to find

food and escape predators.

The Law of Inheritance of Modified Characteristics.

The physical changes acquired by parents during their lifetime could be

passed on to their offspring.

Test answer…

Explanation of the long legs and necks in giraffe using Darwinian Evolution

Differences between Lamarck and Darwin’s Theory

 

Darwin 

Lamarck  1

Genetic change is random; adaptive changes arise by

chance, before any need for them arises. The

environment selects the best-adapted individuals

from the population.

  1

 Genetic change occurs in response to need; ie the

environment causes adaptations to develop.

 2

Changes in the body (somatic changes) acquired

during the life are not handed on to the offspring.

 2

Adjustments resulting from sustained use of the body are

handed on to the offspring.

Table comparing Lamarck’s Theory and Darwin’s Theory

ACTIVITY 3

Darwin’s Natural Selection WorksheetRead the following situations below and identify the 5 points of Darwin’s natural selection. There are 2 types of worms: worms that eat at night (nocturnal) and worms that eat during the day (diurnal). The birds eat during the day and seem to be eating ONLY the diurnal worms. The nocturnal worms are in their burrows during this time. Each spring when the worms reproduce, they have about 500 babies but only 100 of these 500 ever become old enough to reproduce.a. What worm would be naturally selected for?Darwin's 5 points: Identify the 5 points in the scenario above.Population has variations. _________________________________________________________________Some variations are favorable. _________________________________________________________________More offspring are produced than survive_________________________________________________________________Those that survive have favorable traits. _________________________________________________________________A population will change over time. _________________________________________________________________

Some worms eat at night and some eat during the day.

Nocturnal worms

Nocturnal worms were not eaten.

Of the 500 offspring produced 100 survived.

The diurnal worms were being eaten so wouldn’t reproduce, only the nocturnal worms reproduced.

Eventually only nocturnal worms would survive.

There are 3 types of polar bears: ones with thick coats, ones with thin coats and ones with medium coats. It is fall, soon to be winter. The temperatures are dropping rapidly and the bears must be kept warm, or they will freeze to death. Many of the bears have had ~2 cubs each but due to the extreme temperatures, many mothers only have one

cub left. a. What bear will be naturally selected for? __________________________________Darwin's 5 points: Identify the 5 points in the scenario above.Population has variations. ______________________________________________________________Some variations are favorable. ______________________________________________________________More offspring are produced than survive._____________________________________________________________Those that survive have favorable traits. _____________________________________________________________A population will change over time. ______________________________________________________________

Bears with thick coats.

Bears with thick coats, thin coats and medium coats.

Bears with thick coats.

Mothers have 2 cubs only one survives.Bears with thick coats.

Only bears with thick coats will survive.

In ostriches, there are 2 types: ones that run fast and those that run slowly. The fast birds can reach up to 40 miles an hour. Jackals love to eat ostrich, and they can reach speeds of up to 35-40 miles per hour. A flock of ostrich will lay 10 eggs (each mother only lays 1),but many rodents break into the eggs and eat the foetus before they hatch.a. What ostrich will be naturally selected for? Darwin's 5 points: Identify the 5 points in the scenario above.Population has variations. __________________________________________________________________Some variations are favorable. __________________________________________________________________More offspring are produced than survive.__________________________________________________________________Those that survive have favorable traits. __________________________________________________________________A population will change over time. __________________________________________________________________

Ostriches that are fast and look after their eggs.

Ostriches that are fast and slow and some look after their eggs, whilst others don’t.Ostriches that are fast can run away from jackals and baby ostriches will hatch.Many eggs are laid (10) many of which are eaten.

Ostriches that are fast and look after their eggs.

All ostriches will be fast and look after their eggs.

Activity 10.2 pg. 201

1.1 HMS Beagle1.2 Galapagos Islands1.3 finches

2.1 D2.2 B2.3 A

3. Organisms evolved in response to the environment; not because they wanted to.Little evidence to support that acquired characteristics are passed on go future generations.

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Theory of evolution by natural selection.

Within a population there is a large number of offspring produced.The offspring are genetically different from each other: the offspring shows

variation.Off spring compete for resource and or something happens, a drought, fire, which acts as a selection pressure causing organisms to compete for limited resources.Those organisms with the genetic traits that allow them to survive will and will pass

the traits on to future generations.Those with the “undesirable” traits will die and will not pass these traits on to future

generations. The undesirable traits will be lost to the population.We say those that have survived have been naturally selected for.

Diagram showing Natural Selection

Graph showing gradualismGraph showing

punctuated equilibrium

Speciation

Allopatric Speciation of the Galapagos tortoises

Diagrams showing how bacteria become Resistant to antibiotics.

Treatment

for MDR TB

lasts 24

months.

Treatment for MDR TB is 100X more expensive than TB.

Treatment for MDR TB has more

side effects than TB.

Activity 6 (Isaacs pg. 211 10.8)

1.1 fossils1.2 species1.3 population1.4 finches1.5 natural selection1.6 allopatric speciation1.7 homologous structures1.8 analogous structures

2.1 Natural Selection2.2• Within a population, there is a large number of offspring.• Individuals within the population show genetic variation. Some are

tall and some are short.• The tall individuals are able to eat the high hanging fruit and survive.• The reach adulthood and pass their “tall” genes on to future

generation.• The short individuals starve and die. They do not pass their “short”

genes on to future generation.• Eventually only tall individuals will be present in the population.

3.1 Some tortoises have rounded shells and some have flattened shells.3.2 The tortoises from Hood Island.3.3 Those from Pinta Island.3.4 These tortoises have more or less the same shaped shell, so they

will be able to go to the same burrows etc. as the Hood Island tortoises. Also they have the second longest neck so they will be able to reach up to the same vegetation as the Hood Island tortoise.

4.1.1 The population consisted of more susceptible mosquitoes compared to the few resistant mosquitoes.

4.1.2 Only the resistant mosquitoes survived.

4.2 Equal numbers of resistant and susceptible mosquitoes survived. The susceptible mosquitoes did not out number the resistant

mosquitoes.4.3 There are more mosquitoes after the second pesticide application because there were more resistant mosquitoes in the population prior to being treated.

4.4 They were not able to survive the pesticide application. They were unable to produce offspring to pass that gene on to future generations.

Natural Selection

• Within a population, there is a large number of offspring.• Individuals within the population show genetic variation. Some are

resistant to pesticide and some are not resistant and are susceptible.• The resistant individuals are able survive the pesticide application and

survive.• They reach adulthood and pass their “resistant” genes on to future

generation.• The susceptible individuals die. They do not pass their “susceptible”

genes on to future generation.• Eventually only resistant individuals will be present in the population.

5. One of the observations Darwin made during his study

of pigeons was about artificial selection. In 1859 Darwin and Wallace jointly proposed that new species

could develop by the process of natural selection.

Using an example each, describe natural and artificial selection and also highlight the differences between

these two processes.