Transcript Life Over Time - chapter 6

Life Over Time - chapter 6
Life Over Time - chapter 6
6.1 Earth has been home to living things for about
3.8 billion years.
A. Fossils provide evidence of earlier life.
1. Types of fossils
 ex. bones, trilobites
Life Over Time - chapter 6
6.1 Earth has been home to living things for about
3.8 billion years.
A. Fossils provide evidence of earlier life.
1. Types of fossils
 ex. bones, trilobites
2. Finding the age of fossils
 relative dating – comparing fossils
 absolute dating – uses radioactive elements
(Carbon 14)
3. Assembling the fossil record
Life Over Time - chapter 6
B. More complex organisms developed over time.
1. Unicellular organisms (3.8 billion years ago)
2. Multicellular organisms (1.2 billion years ago)
3. Life on land (0.5 billion years ago)
Life Over Time - chapter 6
C. EarthΥshistory includes mass extinctions.
1. Permian Extinction
 90% of ocean life became extinct (250 million years ago)
 many land animals also became extinct
 why?  earthΥslandmasses collided forming Pangaea
Life Over Time - chapter 6
C. EarthΥshistory includes mass extinctions.
1. Permian Extinction
 90% of ocean life became extinct (250 million years ago)
 many land animals also became extinct
 why? - earthΥs andmasses
l
collided forming Pangaea
2. Cretaceous Extinction
 dinosaurs became extinct (65 million years ago)
 many other animals also became extinct
 why? - meteorite collided with Earth
Life Over Time - chapter 6
6.2 Species change over time.
A. Scientists explore the concept of evolution.
1. Early ideas – Lamarck (acquired traits)
2. Darwin’s observations
 Galapagos Island
 tortoises – neck length

finches - types of beaks - -
Life Over Time - chapter 6
6.2 Species change over time.
A. Scientists explore the concept of evolution.
1. Early ideas – Lamarck (acquired traits)
2. Darwin’s observations
 Galapagos Island
 tortoises – neck length

finches - types of beaks - B. Natural selection explains how living things evolve.
1. Overproduction - MANY offspring!
2. Variation – natural or mutation
3. Adaptation – benefit or drawback?????
4. Selection - “survival of the fittest”
Lamarck
-inhertiance of ACQUIRED traits
-- first theories on evolution
-- environment changes animals and then can
pass traits to offspring
Darwin
-theory of natural selection
-- OVAS
-- “survival of the fittest” to live and
reproduce
Lamarck
-inhertiance of ACQUIRED traits
-- first theories on evolution
-- environment changes animals and then can
pass traits to offspring
WRONG - scenario A
Darwin
-theory of natural selection
-- OVAS
-- “survival of the fittest” to live and
reproduce
CORRECT - scenario B
Life Over Time - chapter 6
6.3 Many types of evidence support evolution.
A. Observations provide evidence for theories.
 theories are widely accepted statements based on
observations and evidence
 took 20 years before Darwin published his Galapagos work
Life Over Time - chapter 6
6.3 Many types of evidence support evolution.
B. Fossil evidence supports evolution.
 common ancestors
Life Over Time - chapter 6
6.3 Many types of evidence support evolution.
B. Fossil evidence supports evolution.
 common ancestors
C. Biological evidence supports evolution.
 Similarities in structure (vestigial structures)
 Similarities in development (embryo development)
Life Over Time - chapter 6
6.3 Many types of evidence support evolution.
B. Fossil evidence supports evolution.
 common ancestors
C. Biological evidence supports evolution.
 Similarities in structure (vestigial structures)
 Similarities in development (embryo development)
D. Genetic evidence supports evolution.
 similar genes for similar functions
ex. clock gene in mammals (mouse vs. human)
Quiz Topics - chapter 6: Evolution
- Vocabulary
-Darwin and Lamarck’s theories on evolution
- OVAS textbook (p. 183)
- theory of natural selection (Darwin)
-3 types of evidence to support evolution
-- learnings from ”Virtual Fossil Hunt”