EVOLUTION Topic 18

http://www.youtube.com/watch?v=faRlFsYmkeY

Theory- explanation which has been scientifically tested and supported. Hypothesis- a testable prediction

Evolution- The process by which species change over time Present day organisms developed from earlier, distinctly different organisms.

Theories of Evolution Inheritance of Acquired Traits- “use it or lose it”, Jean Baptist Lemarck Genetic Drift- each generation is slightly different than the previous, changes occur over time

Inheritance of Acquired Traits

Theories of Evolution Spontaneous Generation- living things come from non-living things Gradualism- changes occur gradually over time Punctuated Equilibrium- evolution occurs in short bursts with long periods of stability

Gradualism & Punctuated Equilibrium

Natural Selection Selection of adaptations which are best suited for the environment, adaptations come through genetic mutations

Natural Selection

EVOLUTION ROCKS!

Fossils Any record of organisms that lived in the geological past

Geological Time Scale Simple → Complex Marine → Land Transitional forms of animals Sufficient time for evolution to take place

Anatomical Evidence of Evolution

Scientists compare anatomy to understand how structures are used. Evidence of a common ancestor.

Homologous Structures Have the same, or similar, structure but not necessarily the same function.

Homologous

Analogous Structures Same function but different structure. NOT inherited from a common ancestor.

Analogous

Vestigial Structures Appear to have no use Remains of a structure which had a use in an ancestral species

Vestigial Human Appendix

Human Coccyx (Tail Bone) Vestigial Human Coccyx (Tail Bone)

Vestigial Whale Hip Bones

What happens to vestigial structures? Eventually these structures may be adapted for new uses or slowly lost.

Comparative Biochemistry and Cytology

BIOCHEMISTRY Chemical reactions which take place in living things

PHYSIOLOGY How organ systems work together

What do ALL living things have in common?

What does DNA code for? Proteins- such as hormones and enzymes

Comparative Biochemistry Studying the similarities and differences in chemical reactions in living things.

Theory of Endosymbiosis

Larger cells engulfed smaller cells, then lived together- symbiotic relationship

Mitochondria and chloroplasts have DNA! Both contain ribosomes! Both reproduce independently!

Comparative Embryology Embryo- an organism in the early stages of development

Endosymbiosis http://go.hrw.com/resources/go_sc/interactOnline/hx/hxlif_io.swf

NATURAL SELECTION

VARIATION within a species Individuals with a population have characteristics which differ IMAGES: https://www.msu.edu/course/bs/110/ebertmay_S08/notes/snotes/2_14_08_evolution1.html http://www.bbc.co.uk/schools/ks3bitesize/science/organisms_behaviour_health/variation_classification/revise4.shtml

ARTIFICIAL SELECTION IMAGE: http://visual.merriam-webster.com/animal-kingdom/carnivorous-mammals/dog-breeds_2.php

Natural Selection Sexual selection- choosing a mate Becoming prey- will you be eaten? Ability to reproduce- Will your genes be passed on?

SELECTION IMAGES: http://core.ecu.edu/biol/summersk/summerwebpage/topics/sex_selec.html http://www.bio.miami.edu/ecosummer/lectures/lec_symbiosis.html

FITNESS Best adapted for the conditions Not necessarily the largest or strongest IMAGE: http://www.inshapeladiesfitness.webs.com/

Natural Selection Tale of the Peacock http://www.youtube.com/watch?v=gKybAp--n7M

ADAPTATIONS

Adaptation A change that occurs in a population in response to environmental changes

Adaptive Radiation A small group within a population develops its own gene pool Certain traits become different from the original population’s traits Then become 2 separate populations

Effects of Adaptive Radiation New species are able to fill in needed roles in their environment.

Geographic Isolation A population is separated from the original population. Gene pools divide, forming new species

Speciation The formation of a new species which has diverged from another

COMPETITION

Competition for… Food Water Space Nesting Sites

IMAGE: http://www. bbc. co

IMAGE: http://www.natureinstitute.org/txt/ch/moth.htm

IMAGE: http://www.natureinstitute.org/txt/ch/moth.htm

Pepper Moths http://www.techapps.net/interactives/peppermoths.htm

Extinction A species no longer exists Unable to adapt to changes in environment More variation within a species increases chance of survival

Endangered Species Likely to become extinct http://environment.guardian.co.uk/flash/page/0,,2114873,00.html

CHARLES DARWIN

HMS BEAGLE

GALAPAGOS ISLANDS

Natural Selection Overproduction Competition Survival of the Fittest Reproduction Speciation

Evolution is happening NOW!

PESTICIDE RESISTANCE Some insects survive Pass on genes to be resistant to pesticides

ANTIBIOTIC RESISTANCE Certain strains of bacteria are resistant to antibiotics Continue reproducing Pass genes that resist antibiotics

Interactive Galapagos http://www.pbs.org/wgbh/nova/evolution/explore-galapagos.html