Evolution- Phylogeny Flashcards Preview

Evolution, Ecology, and Biodiversity > Evolution- Phylogeny > Flashcards

Flashcards in Evolution- Phylogeny Deck (21)
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1

What is systematics?

An analytical approach to understanding diversity and relationships of organisms both extant and extinct

2

What are the categories of classification?

Domain, kingdom, phylum, class, order, family, genus, and species

3

What is a taxon?

The taxonomic unit at any level

4

What is a phylogenetic tree?

A hypothesis about evolutionary relationships

5

What are sister taxa?

Groups that share an immediate ancestor

6

What is a polytomy?

A branch from which more than 2 groups emerge

7

What don't phylogenetic trees do?

They don't show patterns of descent and they don't indicate when species evolved or how much change has occurred

8

What is convergent evolution?

Similar environmental pressure and natural selection produce similar adaptation in organisms for different evolutionary lineages

9

What are non-homologous traits and what is another word for them?

Structures or molecular sequences that evolved independently. Another word is homoplasy

10

What is a cladogram?

A hypothesis depicting patterns of shared characters among taxa

11

What is a clade?

It is within a cladogram. It is a group of species that includes ancestral species and all its descendants

12

What does a paraphyletic group consist of?

An ancestral species and some, but not all, of the descendants

13

What does a polyphyletic group consist of?

Various species that lack a common ancestor

14

What is the difference between shared ancestral and shared derived characters?

Shared ancestral characters originate in an ancestor of a taxon. Shared derived characters is unique to a particular clade

15

What are the two things the length of a branch can represent in phylogenetic trees?

1. Reflect the number of genetic changes that have taken place in a particular DNA sequence in that lineage
2. Reflect chronological time

16

What are molecular clocks?

They uses constant rates of evolutions in some genes to estimate the absolute time of evolutionary genes

17

What are some difficulties with molecular clocks?

- Not as smooth as neutral theory predicts
- Some DNA changes are favoured over others
- Estimates of evolutionary divergences older than the fossil record have a high degree of uncertainty

18

What are the 3 domains?

Bacteria, Archaea, and Eukarya

19

What does the tree of life suggest and what is is based on?

Eukaryotes and Archaea are more closely related to each other. It is based largely on rRNA genes that have evolved slowly

20

Who is Doolittle?

First to show importance of horizontal gene transfer

21

What is horizontal gene transfer?

The movement of genes from one genome to another