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Presentation on theme: "UNIT B: EVOLUTION Messana."— Presentation transcript:


2 Evolution Movie Clip

3 SECTION #1B: Unicellular: Single–cell; 1 cell Ex: Bacteria Multicellular: 2 or more cells Ex: Algae Mammals:

4 Mass Extinction When a large # of species DIE out suddenly
2 Major Ones: 1) Permian- 250 million yrs ago (end of Paleozoic Era) 90% of OCEAN LIFE died out ….the LARGEST MASS EXTINCTION!! 2) Cretaceous - 65 million yrs ago (end of Mesozoic Era) Dinosaurs became extinct

5 Section #2: BIOLOGICAL EVOLUTION – Process through which SPECIES CHANGE over time due to a CHANGE IN GENETIC MATERIAL that is passed through GENERATIONS.

6 Theory of Evolution 1st Life with David

7 EARLY IDEAS: LAMARCK: (p 18B) French
Animals ACQUIRED traits during their lifetime and passed them on to their OFFSPRING EX: DARWIN: (p 19B) British NATURAL SELECTION – members of a species that are BEST SUITED to the ENVIRONMENT (nature) will survive & reproduce. SURVIVAL of the FITTEST! 4 principles to support EX: Beaks of Finches (Galapagos Islands)


9 Charles darwin


11 Voyage of Beagle Dates: February 12th, 1831 Captain: Charles Darwin
Ship: H.M.S. Beagle Destination: Voyage around the world. Findings: evidence to propose a revolutionary hypothesis about how life changes over time

12 Vogage route

When plants or animals REPRODUCE, it makes MORE OFFSPRING than actually survive & reproduce EX: fish & turtle eggs

14 Overproduction

15 VARIATION There are NATURALLY occurring differences in TRAITS due to different GENETIC MATERIALS or due to MUTATIONS-this is the PHENOTYPE of the organism (HOW it LOOKS on the outside) Variations get “passed on” EX: BROWN vs BLUE eyes

16 MORE VARIATION… EX: NEMO had a short fin
NO 2 zebras have the same STRIPE pattern


ADAPTATION: INHERITED TRAIT that gives an organism an “A”dvantage” in its environment over other members. EX: Move faster (cheetah); blend in (lions); camouflage (chameleon); shape of tail fin (fish) SELECTION: Organisms with an ADAPTATION will SURVIVE & REPRODUCE and PASS ON the ADAPTATION “SURVIVAL OF THE FITTEST!”

19 ADAPTATION “Inherited” trait that gives an organism an ADVANTAGE in its particular environment over other members of the group EX: - Fish with curved tail swim faster (speed) - White fur rabbits blend in to snow better in arctic climates (camouflage) - Birds with stronger beaks can get food better (feeding) Bears can hibernate when their food source is scarce Beetle with horns can fight off beetle without horns (defense)

20 Adaptation Activity Will YOU survive????? I Will Survive!


22 Human who wants 2 fly Problem: NO wings!!!

23 Plane…..with wings…..

24 Adaptation: non winged human jumps from winged vehicle

Evolution of a NEW SPECIES from an old species, due to ENVIRONMENTAL CHANGE “SPECIATION is due to ISOLATION!!! 2 populations of SAME SPECIES separated; can’t reproduce; differing mutations occur; each evolves – 2 DIFFERENT SPECIES “ISOLATION causes SPECIATION” A1 A2

26 Evidence for Evolution:
1) Fossil Record 2) Biological Evidence: A.)Homologous Structures = similar structure with different function, means common ancestry (Ex: forelimbs) B.)Analogous Structures = similar function, but not from common ancestor C)Vestigial Organ = organ or structure used in an ancestor, still present but not used in the evolved organism (Ex: leg bones in whales, appendix in humans)

27 Homologous Structures

28 Vestigial Organs

29 Evidence of Evolution: Fossils
Fossils – show change in a single species over time or similarities between species Evolution of the Modern Horse

30 Evidence of Evolution: Comparative Anatomy
Analogous Structures – different anatomical structure but similar function that arise from common environmental demands

31 Human Vestigial Organs

A) Similarities in embryology B)Matching gene/DNA sequences

33 Evidence of Evolution: Molecular Biology
Molecular Biology - the genetic structure of an organism The key to understanding how traits are passed from one generation to the next is DNA analysis Scientists can tell how closely related organisms are by studying their DNA There does not have that much of a difference in a gene sequence to be a different organism!

34 Evidence of Evolution: Embryology
Embryology – shows similar developmental stages amongst different species

35 Similarities in Embryos


37 Humans Speeding Up Evolution

38 Phenotypes

39 Homologous/Vestigial Structures

40 Example of Evolution So how do animals and plants adapt to their environment over time? Elephant Adaptation Video- shows how evolution of the Earth affects the evolution of a species


42 Which Brings Us Back To…
Natural Selection Or “Survival of the Fittest” What does “Survival of the Fittest” really mean? In the next few scenarios,describethe phenotype that would most likely be “selected” to survive…


44 Survival of the Fittest
Scenario 1: Drought There has been a drought and all of the grass has dries up and dies first, but the leaves on bushes and trees are slower to die…who survives the longest? Animals with short legs but long necks Animals with long legs, but short necks Animals with both long legs and long necks Animals with both short legs and short necks


46 Survival of the Fittest
Scenario 2: Predator is Approaching A predator is approaching the herd, but is not hunting yet…who will know sooner and therefore have a better chance to escape?


48 Survival of the Fittest
Scenario 3: Predator Fight A predator has arrived. It is too late to run away or hide, the animals must fight off the predator…who has the best chance at fighting?


50 Survival of the Fittest
Scenario 4: Blizzard The weather becomes very cold. There is a blizzard and the land is covered in snow…who survives?


52 Survival of the Fittest
Scenario 5: Volcanic Eruption There has been a volcanic eruption. Lava flows down the mountain onto the plains and kills anything in its path…who will make it?

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