Classification & Evolution Power Hour

Learning Targets I can list the 6 kingdoms of life and provide characteristics of each. I can use a classification key to identify organisms based on internal and external features. I can provide evidence of how evolution explains the diversity of species on Earth today. I can give examples of physical and behavioral adaptations that result in better survival and reproduction during an environmental change, and predict which organisms will most likely go extinct (Natural Selection). I can infer how closely related two species are based on anatomical features, cell structures, patterns of development, and genetics.

Why Classification? Helps in naming organisms Aids in grouping organisms Makes it easier to see connections between organisms Shows evolutionary relationships

Dichotomous key: a tool used to identify organisms using a list of observable traits. Greek for cutting into 2 parts Groupings based on similar features

Dichotomous Key Example: Has pointed ears .................................... go to 3 Has rounded ears ....................................go to 2 2. Has no tail ............................................. Kentuckyus Has tail .................................................. Dakotus 3. Ears point upward ................................. go to 5 Ears point downward .............................go to 4 4. Engages in waving behavior ................... Dallus Has hairy tufts on ears ............................Californius

From a dichotomous key you should be able to: Determine physical characteristics that are used to identify a species. Example: shape of ears or presence of tail Identify an organism from other similar organisms.

Kingdoms of Life All living things are divide into 6 kingdoms based on: If they have their DNA in a nucleus If they are multi- or single-celled How they get their energy/food How they move (or don’t move)

Kingdoms of Life Archaebacteria Eubacteria Protists Fungi Plants Animals *Prokaryote – No nucleus, very simple cells *Eukaryote – DNA in a nucleus, more complex cell organelles

Prokaryotes Archaebacteria: single-celled, live in extreme environments. Examples: deep sea vents, hot springs Eubacteria: single-celled, live everywhere, even in YOU. Examples: E. Coli, Bacillus anthracis; Clostridium tetani; Clostridium botulinum

Eukaryotes PROTISTS: Mostly single celled, immobile or can move by cilia, flagella Examples: Paramecium, Ameoba, Volvox

Eukaryotes FUNGI: mostly multi-celled, except yeasts and molds. Are Decomposers: they get their energy from decomposing matter Examples: Crimini mushrooms, portabello, shitake, Amanita, athletes foot, bread yeast

Eukaryotes PLANTS : Multi-celled, Autotrophs – use the chloroplasts in their cells to get their energy by making their own food from the sun; and immobile. Examples: trees, shrubs, ferns, conifers, grass, flowers, etc.

Eukaryotes ANIMALS – multi-cellular, Heterotrophic – they get their energy/food by ingesting other organisms, move independently.

Evolution Lamarckian Evolution – acquired traits are passed on to offspring. This theory is disproven. Darwinian Evolution – organisms born with advantageous traits or adaptations will be more likely to reproduce and pass on their traits. Charles Darwin Jean Baptiste Lamarck

Evolution Animals cannot evolve or become better adapted to its environment during its lifetime. Evolution is the change that occurs over time in the hereditary traits of a species It is an ongoing process, occurring in organisms today.

Natural Selection Genetic Variation in a species The environment selects which traits are adaptations, and which traits are harmful. Those with adaptations live longer and reproduce more, passing on their genes & traits. Green beetles disappear, brown beetles become more common.

VARIATION Differences within a species, and are genetic; in the DNA they are born with. DNA is the source of all variations. Mutations are the source of variations, and origins of new species. An adaptation is any variation in a trait that makes an organisms better suited to its environment. In a new environment, old harmful mutations can become adaptations. Example: Battle of the beaks, Darwin’s Finches, Peppered Moths

What is the science behind this theory? Fossils—any remains of life from an earlier time and the most abundant evidence for evolution

How do scientists figure out how old fossils are? Relative dating – looking at where the rock is located. Older layers are deeper than the layers above. This method only provides an estimated age of a fossil. Stratigraphy Carbon dating is more precise.

2) Homologous Structures —body parts that are similar in origin and structure. Example: arms, dolphin fin, bat wing, bird wing

3) Vestigial Structures —a body part that is reduced in size and does not seem to have a function. Examples: human appendix, wisdom teeth and muscles that are for moving the ears; pelvis bones in whales.

4) Embryology —study of the development of embryos (an organism in its earliest stages of development). Examples: gills and tailbones in humans                

What similarities do you see between these embryos?

5) Biochemical & DNA Comparing DNA —the closer the DNA sequences are in organisms, the more closely related they are. Example: DNA has shown that dogs are the closest relatives of bears. Human’s closest relatives are from the ape family. Cousins?

Example: Humans are most closely related (99.9%) to chimpanzees.

Thank you for coming. The test will be on Friday, March 28th. Any Questions? Thank you for coming. The test will be on Friday, March 28th.