EVOLUTION CHANGES OVER TIME

Transcription

1 EVOLUTION CHANGES OVER TIME Life Science 7 th grade Ms.Akers

2 UNIT 6 EVOLUTION (STANDARDS) S7L5 Students will examine the evolution of living organisms through inherited characteristics that promote survival of organisms and the survival of successive generations of their offspring. S7L5a Explain that physical characteristics of organisms have changed over successive generations (e.g. Darwin s finches and peppered moths of Manchester). S7L5b Describe ways in which species on earth have evolved due to natural selection. S7L5c Trace evidence that the fossil record found in sedimentary rock provides evidence for the long history of changing life forms.

3 UNIT 6 - EVOLUTION: STUDENT LEARNING MAP TOPIC: Evolution KEY LEARNING: Through natural selection, organisms evolve and adapt to survive and fossils provide evidence of an organism s presence on Earth. UNIT ESSENTIAL QUESTION: What type of evidence supports life existed and changed before our time?

4 UNIT 6 - EVOLUTION: SLM CONCEPT 1: Fossils and Pangaea Lesson Essential Questions: 1. How are fossils formed? 2. How is the age of fossils determined? 3. How do fossils support the theory of Pangaea? Vocabulary: evolution, gradualism, punctuated equilibrium, Pangaea, continental drift, fossil, relative dating, radiometric dating

5 EVOLUTION Evolution-Change over time Involves genetics Includes adaptations - an inherited trait that increases an organisms chance of survival to reproduce which occurs over many generations.

6 THEORY VERSUS FACT Fact A scientific observation known to be true. Theory A broad concept, thought to be true because it explains many facts.

7 THEORY OF CONTINENTAL DRIFT PANGAEA Earth formed 4.6 BYA (Billion Years Ago) 1915, Alfred Wegener studied similar plant and animal fossils found on different present-day continents. He theorized continents once formed one giant supercontinent called Pangaea. Then, 245 MYA, Continental drift -Movement of Earth s continents took place due to tectonic plates shifting.

8 (S7L5a,b) Speed of Evolution: When the continents drifted, this led to changes. Gradualism-A slow, ongoing process by which one species changes to a new species versus Punctuation equilibrium- Rapid evolution that comes about when the mutation of a few genes results in sudden change (appearance) of a new species

9 FIVE TYPES OF FOSSILS S7L5C Imprint- Sediment fills an organisms track Mineralized- Minerals seep into pores of wood or bone, dissolve the organic matter, then crystallize retaining its cell structure shape. Frozen- organism trapped in mud, tar, then temperature drops fast & organism freezes instantly! (rare) Ex: Ice Age Fossils in amber- sticky resin of certain conebearing plants/trees traps insects/organisms. DNA can be extracted. Ex: Jurassic Park Cast- organism decomposes and leaves a cavity (space) that fills with sediment or minerals.

10 SOLID FORMS OF PLANTS AND ANIMAL FOSSILS S7L5C (MADE FROM SEDIMENT: MUD, SAND, OR VOLCANIC ASH)

11 FOSSIL RECORD: DETERMINING A FOSSIL S AGE S7L5C Absolute Dating VS. Relative Dating Estimating the age of SEDIMENTARY rocks or fossils by comparing the amount of radioactivity elements to others. *Can be inaccurate In an undisturbed area, where younger rock layers are deposited on top of older rock layers. *Earthquake or plate movement can disrupt accuracy.

12 FOSSIL RECORD : AGE OF FOSSILS (S7L5C)

13 GEOLOGIC TIMELINE DATING THE AGE OF FOSSILS (COPY PG.196) (S7L5C)

14 UNIT 6 SLM: S7L5A NATURAL SELECTION, S7L5B-CHANGE IN PHYSICAL CHARACTERISTICS CONCEPT 2: Charles Darwin and Natural Selection Lesson Essential Questions: 1. What is Darwin s role in the theory of evolution? 2. What are the different speeds of evolution? 3. What is Darwin s theory of evolution by natural selection? Vocabulary: fossil, finches, peppered moths,camouflage, variation, overproduction, natural selection, competition, adaptation.

15 CHARLES DARWIN: VOYAGE ON HMS BEAGLE 1831-left England Sept. 15,1835 -Visited Galapagos Islands off coast of South America 1836 Returned England

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17 CHARLES DARWIN (S7L5A,B) Studied plants and animals as a Naturalist on HMS Beagle - British ship. Finch species geographically isolated on different island environments. Finch populations evolved adaptations that aided their survival result = new species. Adaptation- a trait (genetic characteristic) that improves an organisms ability to survive and reproduce in a certain environment Examples: (beak, fur, camouflage) Speciation- new species occurs from 3 events: Separation, Adaptation, and Division

18 DARWIN S FINCH S ON GALAPAGOS ISLANDS AND SOUTH AMERICA BEAKS DIFFER TYPES OF FOOD EATEN (SMALL LARGE) PHYSICAL CHARACTERISTICS CHANGE OVER TIME (INSERT FOLDABLE IN NOTEBOOK)

19 DARWIN S FINCH S (S7L5A) PHYSICAL CHARACTERISTICS CHANGE OVER TIME VESTIGIAL STRUCTURES - EXAMPLE: BEAKS Probing bit-insect eaterfeeds in trees. (4) Probing bit-insect eater that uses a twig or cactus spine to probe insects. (3) Grasping bit-insect eater that feeds in trees. (2) Crushing bit-cactus seed eater. (1)

20 DARWIN S FINCH S (S7L5A) PHYSICAL CHARACTERISTICS CHANGE OVER TIME "Calmodulin is a protein that binds and activates certain enzymes, which triggers a signal that eventually turns specific genes on or off," explains Arkhat Abzhanov, an evolutionary biologist at Harvard. The signals alter the behavior of cells responsible for beak sculpturing.

21 DARWIN S FINCH S (S7L5A) As climate changes in the Galapagos the finch s changed body size, beak size, and beak shape (a measure of width, length and depth). In 1983, after heavy rains, depth of average finch beak returned to pre-drought size, and "evolutionary change" reversed. Explore Evolution, p.

22 CHARLES DARWIN- POLLUTION CHANGES THE ENVIRONMENT As coal-burning factories were built, air pollution increased blackened the trees with soot. On this dark background, the pale typical moths were no longer well-camouflaged and were easily caught by birds, but the carbonaria moths were harder for birds to see, so more carbonaria survived to breed and pass on their genes, and this dark type of peppered moth became more common. By 1895, 98% of moths in heavily-polluted Manchester were carbonaria. Armed with Darwin s new theory of natural selection, J.W. Tutt, an English entomologist, hypothesised in 1896 that the change in colour was due to selection pressure based on how often birds were able to spot the moths.

23 CHARLES DARWIN: S7L5 A,C CREATE A FOLDABLE/BROCHURE/NEWSLETTER Must include the following items: 1. Cover page: name, date, period, & Title 2. Who is Charles Darwin? 3.How does Darwin s theory of evolution support the theory of Pangaea? 5. Describe what he learned about the Galapagos finches. 6. Describe what he learned about the peppered moths. 7. Minimum of 3 Pictures 8. Resource(s): Book pgs., Notes, etc.

24 NATURAL SELECTION -(S7L5B) Process where individuals better adapted to their environment are more likely to survive and reproduce than other members of the same species. Involves genetics (traits) Occurs over many generations Survival of the fittest Only the strong survive

25 NATURAL SELECTION (S7L5B) Overproduction- Too many offspring; not enough resources (food, water, habitat) usually die. Competition- competing against other offspring food or mates Variations Differences between individuals of same species Selective- When the environment selects organisms with helpful traits

26 DARWIN - TREE OF LIFE organized beings represent a tree.(different species branch off 1).

27 CLADOGRAM (TREE OF LIFE): (S7L5A,B,C) Cladogram: A diagram or model of relationships between extinct and living species. Each branch represents a group of organisms that descended from 1 species. html Label the following Cladogram: Amphibian, mammal, bird, or fish?

28 WHALE EVOLUTION PBS video Clips: Whale Evolution and Fish w/ Fingers Evolution Clip Videos & Pgs hstuds/unit3.html

29 PRESENT TIME

30 QUIZ BELOW

31 RESOURCES finches.html