topic: evolution aim: explain the today’s theory of evolution. do now: sit next to your 6...
TRANSCRIPT
TOPIC: EvolutionAIM: Explain the today’s theory of
evolution.
Do Now: Sit next to your 6 o’clock partner for the Genetics Review on the next slide.
Take out Selective Breeding ISN.
HW: Study for tomorrow’s genetics test!
The R allele represents wrinkled seeds. The r allele represents smooth seeds.
1.Cross 2 heterozygous parents.
2.What percentage of the offspring will most likely show the dominant trait?
75%
The illustration traces the development of the corgi dog over several generations as a result of human activity.
Identify the technique being used.
Selective Breeding
Hybridization
One way to produce large numbers of genetically identical offspring is by
1.cloning.
2.fertilization.
3.changing genes by agents such as radiation or chemicals.
4.inserting a DNA segment into a different DNA molecule.
Many diabetics are now using insulin that was made by certain bacteria. The ability of these bacteria to produce insulin was most likely the result of
1.deleting many DNA segments from bacterial DNA
2.genetic mapping of bacterial DNA to activate the gene for insulin production
3.inserting a portion of human DNA into the ring-shaped DNA of bacteria
4.using radiation to trigger mutations
Review:
1.Explain the theory of Natural Selection.
2.Explain what Darwin meant by the term overproduction.
3.Explain what organisms compete for and what the result of competition is.
4.Explain what Darwin says about variation.
5.Describe ‘Survival of the Fittest.’
6.Describe speciation.
Sources of genetic variation in a species
• Mutations (changes in DNA)
• Sexual Reproduction
• Genetic engineering
• Selective breeding
• Migration: moving into or out of an area
Rate of Evolution
1.Gradualism
• Evolution occurs SLOWLY & CONTINUOUSLY through time
2. Punctuated Equilibrium
• Sudden changes in a species after long period of no change
•Ex: Many bacteria have evolved resistant to certain antibiotic
• Penicillin has been in use since 1943. It originally came from the fungus Penicillium.
• 1947: Species of bacteria that cause pneumonia and other infections already had developed resistance to the drug.
• By the 1990s, several disease-producing bacteria had become resistant to penicillin and many other antibiotics.
Punctuated Equilibrium Today
• When penicillin was used to kill bacteria, those with the penicillin-resistant variation survived, reproduced, and passed this trait to their offspring.
• Over a period of time, this bacteria population became penicillin-resistant.
•*BOTH THEORIES SEEMED TO HAVE OCCURRED DURING EARTH’S HISTORY*
• Those that reproduce at a very fast rate–Ex: bacteria, insects
Which organisms have evolved quickly?
What can cause extinction?
• Very little variation in a species– major environmental change
– adaptation no longer favorable
– all organisms die = extinction
Which population of organisms would be in greatest danger of becomingextinct?
(1) A population of organisms having few variations living in a unchanging environment.
(2) A population of organisms having few variations living in an changing environment.
(3) A population of organisms having many variations living in a unchanging environment.
(4) A population of organisms having many variations living in an changing environment.
Let’s summarize…
1. Explain the two theories about the rate of evolution.
2. Identify some sources of variation.
3. What will cause a species to become extinct?
Which population of organisms would be in greatest danger of becomingextinct?
(1) A population of organisms having few variations living in a unchanging environment.
(2) A population of organisms having few variations living in an changing environment.
(3) A population of organisms having many variations living in a unchanging environment.
(4) A population of organisms having many variations living in an changing environment.
Which statement could best be inferred from the information in this diagram?(1) Evolution does not involve gradual change.(2) Evolutionary changes can result in extinction.(3) Evolution begins with plants.(4) Evolution produces organisms that all fill the same niche.
Which statement about the rates of evolution for different species is in agreement with the theory of evolution?
(1) They are identical, since the species live on the same planet.
(2) They are identical, since each species is at risk of becoming extinct.
(3) They are different, since each species has different adaptations that function within a changing environment.
(4) They are different, since each species has access to unlimited resources within its environment.
Which concept is not a part of the theory of evolution?
(1) Present-day species developed from earlier species.
(2) Some species die out when environmental changes occur.
(3) Complex organisms develop from simple organisms over time.
(4) Change occurs according to the needs of an individual organism to survive.
Fossil records indicate that between 80 and 60 million years ago the structure of the horned dinosaur underwent rapid changes separated by long periods of stability. This pattern of change best illustrates the concept of
(1) use and disuse
(2) punctuated equilibrium
(3) gradualism
(4) enzyme specificity
A key concept in the modern theory of evolution explains
(1) how new organs arise according to the needs of an organism(2) how variations occur within a species(3) the continued increase in the human population(4) the presence of asexual reproduction within a species
Some scientists suggest that the extinction of dinosaurs resulted from sudden global weather changes caused by the impact of an asteroid on Earth. This event most likely promoted the evolution of new species of animals. These ideas best support the concept of(1) punctuated equilibrium(2) use and disuse(3) gradualism(4) geographic isolation
1. Identify the common ancestor.
2. Identify the species that have become extinct. Why did these species become extinct?