Biodiversity II Lab: Midterm Review

Three Different Kinds of Microscopes

1. Dissecting scope

2. Compound light scope

3. Electron scope

Phylogenetic Tree/Cladogram

Diagram that shows hypothesized evolutionary relationship between species.

Endpoints

Specific data on a phylogenetic tree (like a species).

Branch Points/Nodes

Shared/common ancestor on a phylogenetic tree.

Clade/Monophyletic Group

A group of organisms that includes a common ancestor and all of its descendants.

Paraphyletic Group

A group of organisms that includes a common ancestor but not all of its descendants.

Polyphyletic Group

A group of organisms that includes groups of species with different ancestors.

Divergent Evolution

The process of related species adapting differently to their environment and becoming more dissimilar. Involves species that share a recent common ancestor.

Convergent Evolution

When a similar trait arises between species that do not share a recent common ancestor.

Homology

The morphological and molecular traits that are derived from a common ancestor and are retained.

Homoplasy

Independently evolved but similar traits.

Natural Selection

The process where organisms with traits best suited to their environment survive and reproduce more often than others; this is not survival of the fittest, you just have to not be the worst.

Genetic Drift

Random phenotype/allelic change.

3 Domains of Life

1. Bacteria

2. Archaea

3. Eukarya

Extremophiles

An organism that thrives in physically or geochemically harsh environments that would be deadly to most other life forms.

Pathogenic

Harmful to other organisms.

Cyanobacteria

Bacteria that produce O2 via photosynthesis; ecologically important bc they fix carbon and nitrogen out of the atmosphere.

3 Groups of Cyanobacteria

1. Anabaena

2. Oscillatoria

3. Merismopedia

Anabaena

Cyanobacteria in long chains; has heterocyst and akinete cells. Symbiotic with aquatic ferns and can be found in freshwater, saltwater, hot springs, and top-soil.

Heterocysts

Specialized cells in Anabaena that fix nitrogen; formed during periods of nitrogen limitation.

Akinete Cells

Dormant cells in Anabaena that are resistant to the cold and drying out.

Oscillatoria

Filamentous cyanobacteria found in freshwater, salt water, and hot springs. These colonies slide back and forth against each other to orient to a light source.

Merismopedia

Sheet-like grid cyanobacteria, found in aquatic habitats and freshwater sediments. They can form symbiotic relationships with zooplankton. Held together by a mucilaginous sheath.

Mucilaginous Sheath

A slimy, protective, outer layer made of glycoprotein that surrounds cyanobacteria and certain other algae or plant tissues.

Gram Staining Technique

Staining technique developed by Hans Christian Gram to differentiate gram positive and gram negative bacteria.

Order of Gram Stain Process

1. Transfer

2. Fixation

3. Crystal Violet

4. Gram’s Iodine

5. Decolorization (Ethyl alcohol)

6. Counterstain (Safranin)

Peptidoglycan

Polymer of sugars and animo acids that compose the cell wall of bacteria.

Gram Positive Bacteria

Bacteria with thick peptidoglycan layer with no outer membrane.

Gram Negative Bacteria

Bacteria with a thin peptidoglycan layer and an outer membrane.

Protobionts

Thought to be first single celled organisms, RNA speculated to be it’s genetic material.

Photoautotrophs

An organism that uses light energy to convert inorganic substances and water into organic compounds for food.

Chemoautotrophs

Organisms that make their own organic food using energy from chemical reactions instead of sunlight.

Chemoheterotrophs

An organism that gets both its energy and its carbon by consuming organic compounds.

Obligate Aerobes

Bacteria that requires oxygen to survive.

Facultative Aerobes

Bacteria that use oxygen to survive, but they can survive and tolerate not having oxygen.

Obligate Anaerobes

Bacteria that requires an area with no oxygen to survive.

Aerotolerant Anaerobes

Bacteria that don’t use oxygen to survive, but they can survive and tolerate its presence in the environment.