Theme 1: Topics 1-4

What are the three main components of biodiversity?

Genetic diversity, species diversity, and ecosystem diversity.

What ecosystem services does biodiversity provide?

Provisioning services, regulating services, support services, and cultural services.

What are the four major threats to biodiversity?

Habitat loss, invasive species, overexploitation. and climate change.

How do we classify organisms?

The Linnaean System of Nomenclature (uses Latin)

What are the levels of classification from broad to narrow?

Domain, Kingdom, Phylum, Class, order, Family, Genus, and Species.

What is the difference between Systematics and Phylogeny?

Systematics is concerned both with Taxonomy and Phylogeny. Phylogeny is the evolutionary history and the relationships among a species or group of species.

What is a phylogenetic tree?

A diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor.

What are the steps to building phylogenic trees?

1. List species + traits

2. Pick an outgroup (a species without shared traits)

3. Make a character matrix (who has what trait)

4. Group species by shared derived traits

5. Build tree starting with outgroup

6. Add branches for each new trait

7. Place species at the ends of branches

8. Check: closest species = most shared traits

What is Cladistics?

a method of classifying organisms based on shared derived traits to show evolutionary relationships. It builds family trees (cladograms) that trace common ancestors.

Symplesiomorphy

old trait shared by many species

Synapomorphy

new trait shared by a recent ancestor

What are the limits of hierarchical classification?

1. Higher-level taxa are not directly comparable across lineages.

2. Hierarchical classification does not provide info. on evolutionary relationships

Taxa

A taxon (pl. taxa) is a group of organisms that are classified together.

Shared characteristics

any trait two species (or taxa) have in common eg. backbone in all vertebrates

Clade

A group of organisms believed to have evolved from a common ancestor.

Derived characteristics

a new trait that wasn’t in distant ancestors, eg. hair in mammals

Monophyletic group

a single common ancestor and all of its descendants.

Paraphyletic group

a common ancestor and some of its descendants.

Polyphyletic group

a grouping with no recent common ancestor.

Allele frequency

How common an allele is in a population, an allele is a variant form of a gene located in the same position

inductive reasoning

Specific observations to general conclusion (probable not guaranteed) eg.

“Tairn, Sgaeyl, and Deigh breathe fire, therefore all dragons breathe fire”

deductive reasoning

General statement/rule applied to a specific case (if premises are true, conclusion has to be true) eg.

“All dragons at Basgiath breathe fire, Tairn is a dragon at Basgiath, therefore, Tairn breathes fire”