EVIDENCE OF EVOLUTIONChapter 15-2

Unit 8 Part 2: Notes #1

Turn in Warm-ups from 1/29- 2/6 (Pass towards middle)Warm-up 2/12: • What is Struggle to Survive?

• Give an Example.• Why is struggle to survive key to Natural Selection?

• Give two examples of Evidence that scientist have to support evolution. (You should have learned some in middle school)

Evolution defined…Evolution is a process of gradual modifications

Darwin called this descent with modification

Many animals and plants shared common ancestors and deviated from that common ancestor overtime

Organism 1

Organism 2

Ancestor

Fossils

Fossils provide geologic evidence of evolution

Fossils in older layers are more primitive than those in the upper layers

Transitional Species: - Descent with modification states that newer

species are modified versions of older species- Fossil record contains the intermediates

AnatomyVestigial organs - a group of organs with no

particular use now but may have been useful in ancestors (tailbone coccyx or hip bones in whales)

Anatomy cont.Homologous Structures:

body parts that are similar in structure may have different functions Indicating at some point

way in the past they did the same job and came from a common ancestor

Anatomy cont.Analogous

Structures: same functions but different development ex. a butterfly wing

and a bat wing Indicates that

populations evolved to be better suited to the environment

Warm-up 2/13What is the difference between Homologous

and Analogous Structures?Name 3 ways that the fossil record gives

evidence for evolution.

Evidence for Evolution Part b (continuation of Tuesdays notes)

BiogeographyCertain animals in one location share similar

traits (I.E. marsupials in Australia)

Embryology Similar likenesses in

embryos of organisms is evidence of descent with modification

Biological Molecules DNA RNA ProteinsSimilar proteins means similar DNAThe longer it’s been since they shared a

common ancestor the more differences in protein

EVOLUTION IN ACTION

Chapter 15-3pp. 308-311

Evolution of a population is due to

environment and the interaction of other species

Evolution acts on phenotype, not genotype

Evolution defined…

Humans breed for specific traits causing

differences in species (i.e. dog breeding)

Artificial Selection

Convergent evolution: Organisms with very different ancestors become more alike due to a common environment Ex. fish and whales-

compare analogous structures

Examples of Evolution

Divergent evolution: populations become more and more dissimilar to adapt to the environment-compare homologous structures

Appearance of birds with different sized beaks that are specific for size of bird seed

Population undergoes divergent evolution

until it fills all areas of the environment

Adaptive radiation

Co-evolution: as one species evolves another does (parasites and hosts)