Taxonomy. The Science of Classification

Transcription

1 Taxonomy The Science of Classification

2 How are organisms classified? 1. Scientists begin with similarities in structure and function. -Type of Cell -Unicellular or Multicellular -Mode of Reproduction -Mode of Nutrition -Ability to move 2. Then they look at other factors such as evolutionary connections (phylogeny), habitat, and niche.

3 LEVELS OF CLASSIFICATION Domain Kingdom Phylum Class Order Family Genus Species most general Each level is called a taxon most specific

4 Mnemonic devices make it easy to recall the levels! Domain Kingdom Phylum Class Order Family Genus Species Dumb Kids Playing chicken on freeways Get Smashed

5 Binomial Nomenclature Each organism is given a scientific name based on its genus and species. Written in Latin 1 st word represents genus and 2 nd word represents species The genus is ALWAYS capitalized and the species is NOT! Names can also be underlined or italicized

6 Polar bear Capitalized Lower case Ursus maritimus (genus) (species) Underlined instead of italicized!

7 Which of the following is the correct scientific name of an organism? a.equus caballus b.black stallion c.equus caballus d.horse

8 a. Branta canadensis b. Falcipennis canadensis c. Grus americana d. Recurvirostra americana

9 Evolution Change in a species over time

10 How long did it take to CHANGE? 66 million years ago 54 million years ago 37 million years ago 26 million years ago Present Day

11 There are two models for HOW this change occurs. Gradualism The model of evolution in which gradual change over a long period of time leads to species formation. Punctuated Equilibrium The model in which periods of rapid change in species are separated by periods of little or no change.

12 There are two models for HOW this change occurs. Gradualism The model of evolution in which gradual change over a long period of time leads to species formation. Punctuated Equilibrium The model in which periods of rapid change in species are separated by periods of little or no change.

13 What is natural selection? In a nut shell Better traits easier to survive more likely to reproduce Over time better traits dominate a population

14 What type of mouse is more likely to survive to produce offspring?

15 Biological Fitness Fitness an organism s ability to reproduce and pass their genes on to their next generation Survival of the Fittest Those who are more Fit will be more likely to survive. More Attractive Smarter Stronger More Likely To Survive and Reproduce

16 Principles of Natural Selection 1. Genetic variation exists in a population and is inherited Genes = Traits Genetic Variation = Variation in Traits

17 Principles of Natural Selection 2. Populations tend to produce more offspring than can survive - more is better! WHY?

18 Principles of Natural Selection 3. The environment presents challenges to survival (resources are limited, competition for food, mate, territory)

19 Principles of Natural Selection 4. Individuals that are better able to cope or have advantages over another will leave more offspring. All of this leads to survival of the FITTEST!!

20 Successful reproduction of the fittest members of a population eventually leads to an adaptation within that population. Adaptation A trait produced by natural selection that has become common in a population because it provides a selective advantage.

21 Types of Adaptations Storage Adaptations Camouflage Reproductive Adaptations Adaptations To Food Protection Plant Adaptations

22 Other Mechanisms of Evolution that lead to adaptations. Mutations Gene flow (migration) Genetic drift

23 A mutation could cause parents with genes for bright green coloration to have offspring with a gene for brown coloration. That would make the genes for brown beetles more frequent in the population. Mutations A mutation is any change to the genetic material of a cell. DNA codes for genes, which are responsible for the traits we see. Mutations may produce a different trait that may be an advantage for a species.

24 Gene Flow (Migration) Some individuals from a population of brown beetles might have joined a population of green beetles. That would make the trait and therefore the genes for brown beetles more frequent in the green beetle population.

25 Genetic Drift A random change in the frequency of a trait that occur in small populations. Several green beetles were killed when someone stepped on them and had no offspring. The next generation would have a few more brown beetles than the previous generation but just by chance. Therefore the frequency of the green beetle trait would decrease.

26 SPECIATION How do these changes lead to the formation of new species? Eventually the gene pools of the populations become too different. The populations can no longer interbreed. This is called REPRODUCTIVE ISOLATION.