Creating a Dichotomous Key

Transcription

1 Dichotomous Keys A tool used that allows users to determine the identity of unknown species Keys consist of a series of choices, where the user selects from a series of connected pairs Each pair of choices contains contrasting traits (most of which are observable)

2 Dichotomous Keys A tool used that allows users to determine the identity of unknown species Keys consist of a series of choices, where the user selects from a series of connected pairs Each pair of choices contains contrasting traits (most of which are observable)

3 Creating a Dichotomous Key Choose a single feature that enables you to divide your group into two smaller groups Take each smaller group and repeat the previous step Be sure to indicate to your key users (those using the key) where to go next similar to a Choose Your Own Adventure novel Repeat each step until each species is alone in its own group Number each dividing feature and assign the the letters a and b to the options for that feature Assemble into a flow chart of sorts

4 Comparative Biochemistry Analyzing DNA to determine the percentage of relationship DNA fingerprinting is used to compare relatedness The more base pairs two living things have in common the closer their evolutionary history

5 Comparative Biochemistry Can also mix single strands of DNA from two different species The greater the bonding between complimentary base pairs, the more closely related the two

6 Comparative Biochemistry Can also mix single strands of DNA from two different species The greater the bonding between complimentary base pairs, the more closely related the two

7 Phylogenetic Tree

8 Cladistics Classification scheme based on phylogeny Based on the idea that each group of related species has one common ancestor Cladogram diagram similar to a phylogenetic tree, that can be used to test evolutionary history Not a phylogenetic tree because it does not show how ancestors are related to

9 Viruses Viruses consists of little more than DNA/RNA surrounded by protective protein coat capsid They do not: Have cell structure Have cytoplasm Respire They are not classified in kingdoms of living things They can however

10 Viral Reproduction Lytic Cycle 5 step process: 1. Attachment Virus attaches to a specific receptor site on the host cell membrane 2. Entry Virus injects its DNA/RNA into the host cell Cell could also engulf the virus 3. Replication Virus uses host cell metabolism to copy its DNA/RNA and its proteins 4. Assembly New virus particles are assembled inside the host cell 5. Lysis and Release Host cell breaks open, releasing new viruses

11 Viral Reproduction Lytic Cycle

12 Viral Reproduction Lysogenic Cycle After entry, viral DNA becomes part of host cell s chromosomes as a provirus Host cell divides, it replicates the provirus along with its own DNA Process can occur for years without harm Only when it enters the lytic cycle will the damage be done Viral dormancy of sorts think Cold Sores

13 Other Points about Viruses Many viruses are retroviruses Viruses containing RNA They use an enzyme, that causes the host cell to copy RNA into DNA When copied into DNA, retrovirus become a provirus Ex: HIV (Human immunodeficiency virus) Mutations occur frequently DNA/RNA new varieties or strains of virus are produced Viruses are often used as vectors Genetic engineers, using recombinant DNA technology, can splice or transfer a gene into the genome of a virus, so it can replicate itself quickly Viral vaccines

14 Kingdom Monera Aka. Eubacteria Prokaryotic and unicellular No organized structure Use cilia, flagella, or pili as locomotive organs Nutrition obtain in a variety of ways Photosynthetic Heterotrophic Chemosynthetic

15 Kingdom Monera Classified based on shape: 1. Spherical: coccus 2. Rod-Shaped: Bacillus 3. Spiral-shaped: Spirillum

16 Kingdom Monera Reproduction is most often asexual by Binary Fission However reproduction can also be sexual via Bacterial

17 Kingdom Monera

18 Kingdom Monera Examples: 1. Escherichia coli 2. Streptococcal pharyngitis 3. Mycobacterium tuberculosis

19 Kingdom Archaea Most primitive Unicellular, prokaryotic Heterotrophic Found in extreme environments Hot springs Deep sea vents Reproduce asexually Use cilia, flagella, or pili as locomotive organs

20 Kingdom Archaea Examples: 1. Thermacidophiles Hot, acidic water 2. Halophiles Extremely salty solutions 3. Thermophiles

21 Kingdom Protista Simplest of the eukaryotes Divided into three groups: 1. Protozoa Animal-like protists Heterotrophs Ex: Amoeba 2. Algae Plant-like protists Autrotrophs Ex: Euglena and Diatoms 3. Slime and water molds Fungus-like protists

22 Kingdom Protista Mostly unicellular and aquatic Use cilia, flagella, or amoeboid movement Reproduction is often asexual Binary Fission Sexual reproduction also occurs

23 Kingdom Protista Page 146 Show cases the life cycle of Plasmodium vivax i.e. What causes Malaria Has both asexual and sexual parts to its life cycle