Speciation and Phylogeny

Question 1

Macroevolution

Answer 1

Evolution of taxa through geological time or the derivation of daughter species from preexisting species. All macroevolution is the evolution of a new species.

Question 2

Speciation

Answer 2

Macroevolutionary phenomenon in which existing species give rise to new species through microevolutionary processes. Biodiversity arrises from additive processes of speciation.

Question 3

Typological classification

Answer 3

Classification by appearance and behaviour.

Question 4

Biological Species

Answer 4

Group of populations all of whose members actually or potentially interbreed and produce fertile offspring-actual or potential gene flow.

Question 5

Non Biological Species

Answer 5

Defines species in terms of genetic resources and evolutionary fate.

Question 6

Morphological Species

Answer 6

Based upon physical similarity, appeals to fossils and asexual species.

Question 7

Phylogenetic Species

Answer 7

Phylogenies=family trees-shows evolutionary relationships among organisms. Species are the smallest unit in phylogeny, arise from unique circumstances.

Question 8

Reproductive Isolation

Answer 8

Species generally closely adapted to environment. Adaptations disrupted when species interbreed-reproductive isolation prevents this from happening.

Question 9

Isolating Mechanisms

Answer 9

Prezygotic- Egg and sperm never encounter each other or fertilization doesn’t take place
Postzygotic-Fertilization takes place, but offspring cannot reproduce easily (mules) (reduced hybrid fertility-hybrid breakdown)

Question 10

Temporal Partitioning

Answer 10

Organisms not active/reproducing at the same time

Question 11

Habitat Partitioning

Answer 11

Organisms do not live in same habitat, so they never meet.

Question 12

Behavioural Isolation

Answer 12

Courtship ritual or appropriate signal required before mating takes place.

Question 13

Mechanical Isolation

Answer 13

Male and female sex organs must fit together.

Question 14

Gametic Isolation

Answer 14

Species have specific recognition molecules on the surfaces of their gametes.

Question 15

Allopatric Speciation

Answer 15

Based primarily on spatial separation of founding population from rest of species (blocks geneflow). Followed by establishment of reproductive isolation.

Question 16

Sympatric Speciation

Answer 16

No large scale geographical distance to reduce gene flow, differences among individuals cause them to choose different habitats, resulting in speciation.

Question 17

Polyploid Speciation

Answer 17

Number of chromosomes in an individual doubles, restricting it from mating with others in its species. 80% of plant species.

Question 18

Hybrid Zones

Answer 18

Areas where individuals of two closely related species can meet and possibly interbreed, producing hybrids. Can result in the two species losing their separate identities.

Question 19

Adaptive Radiations

Answer 19

Rapid diversification from an ancestral species into a multitude of different forms-star shaped phylogenies. Happens due to changes in environment.

Question 20

Punctuated Equilibrium Model

Answer 20

Speciation is extremely quick, species stable outside speciation events. Still slow.

Question 21

Gradualism

Answer 21

Gradual speciation, species change slowly through time, may take millions of years.

Question 22

How much time is there usually between speciation events?

Answer 22

On average 6.5 million years.

Question 23

Homologous Structures

Answer 23

Organ inherited from unique common ancestor, modified in various adaptive ways-displays basic common structure.

Question 24

Convergent Evolution

Answer 24

Produces organisms that look very similar but are not closely related-due to similar selection processes acting on ancestors.

Question 25

Analogous Structures

Answer 25

Structures which resemble one another but are not derived from a common ancestor.

Question 26

Systematics

Answer 26

Classification of living species based upon evolutionary relationships.

Question 27

Linnean Classification

Answer 27

Originally set up without evolutionary assumptions, but corresponds well with phylogeny-avoids problems with common names.

Question 28

Binomial Designation

Answer 28

Every species given unique name-genus and species, with scientific description.

Question 29

Genus

Answer 29

Group of similar species, all which share a common ancestor and some homologies which they share with the common ancestor but not any other species. Second lowest level in systematic hierarchy, no emergent properties.

Question 30

Systematic Hierarchy characteristics

Answer 30

Higher levels-more inclusive. Each succeeding level indicates unique common ancestor of all included groups further back in time.

Question 31

Cladistics

Answer 31

Way of erecting phylogenetic tree for groups of taxa whih will result in a classification mapping out the phylogenetic tree as a testable hypotheses.

Question 32

Clade

Answer 32

Evolutionary groups consisting of ancestral species and all of its descendents. Defined by shared derived characteristics

Question 33

What does it mean that shared derived characteristics are uninformed?

Answer 33

All vertebrates have a spinal column, so its presence is of no use in classification among the vertebrates.

Question 34

Doing cladistics requires…

Answer 34

Character matrix and outgroup- known to be distantly related to all members of the group being classified, polarizes character states.

Question 35

Parsimony

Answer 35

The phylogeny requiring the fewest evolutionary changes is best. Have to assume the smallest number of evolutionary steps is actually what happened.

Question 36

Molecular systematics

Answer 36

DNA and molecular similarity should vary directly with evolutionary distance. Can also be used to construct phylogenies, but may disagree with morphological phylogenies.

Question 37

How useful is molecular data?

Answer 37

Mitochondrial DNA- used for high resolution, relatively recent evolution
rRNA- useful for evolution through deep time-kingdoms and domains.