Classifications of living things

Question 1

Define a classification

Answer 1

The grouping of things which allows for identification of things such as animals and living things in biology

Question 2

Explain the classification systems and their function

Answer 2

Physical Features (Observable structural features)
Methods of reproduction
( sexual vs asexual, level of care for offspring)
Molecular sequences
(comparing molecular systems of different organisms)

Question 3

Define Homologous structures

Answer 3

similar structures with different functions- indicates shared ancestry (evidence of divergent evolution)

Question 4

Define Analogous structures

Answer 4

structures with similar function but no structural relationship (evidence of convergent evolution)

Question 5

Vestigial structures

Answer 5

structure with no apparent function, but may have had a function once upon a time

Question 6

Comparative embryology:

Answer 6

development of different organisms over time and their developing similarities

Question 7

Linnaean system

Answer 7

Based classifications on the reproductive system of plants and the similar physical features of animals

Question 8

Taxon

Answer 8

each level of classification and taxa is plural and it is used to reflect how groups evolve

Question 9

Hierarchical system of Taxa

Answer 9

Each taxa have subdivisions and this results in the scientific naming of genus and species

Question 10

Phylogeny:

Answer 10

evolutionary history of a species

Question 11

Molecular phylogeny

Answer 11

evolutionary history of a species using DNA sequencing

Question 12

Clade:

Answer 12

section of phylogenetic tree; group of organisms that consists of a common ancestor and all of its lineal descendants

Question 13

How does molecular Phylogeny changes occur?

Answer 13

• Mutations
  -Isolation (geographically, reproductively)
  Changes are passed down over generations where divergence becomes more pronounced (recall homologous structures) eventuating in separate species

Question 14

What type of DNA?

Answer 14

• Mitochondrial DNA (mtDNA) is the main form used – why?
• Maternal line and so easier to track mutation and rate
  As a result, it is excellent to use for molecular clocks (determining when one species diverged into two new ones)

Question 15

Cladistics:

Answer 15

classification system according to derived characteristics (anatomical, physiological, behavioural and genetic)

Question 16

Common assumptions

Answer 16

Shared common ancestor
Bifurcating pattern: when a lineage splits, it divides into two groups
Physical change: organisms change over time
Plesiomorphic: original
Apomorphic: derived

Question 17

Cladograms

Answer 17

Length of horizontal line does not matter
Is not based off of a timescale
Each node represents a common ancestor

Question 18

Phylogenetic trees

Answer 18

Length of horizontal line does matter
Based off of a timescale (evolution over time)
Each node is the last time they shared commonality of being the same species (not necessarily representative of a common ancestor)

Question 19

Species can also be classified by their interactions with other species.

Answer 19

Symbiosis 
Predation
Competition
Disease
example: A Dingo preys upon a bandicoot. The dingo is the predator and the bandicoot is the prey

Question 20

Symbiosis:

Answer 20

when two species of organisms interact with each other in a close relationship over a long period of time

Question 21

Mutualism:

Answer 21

both organisms benefit from the interaction (+/+)

Question 22

Commensalism:

Answer 22

one organism benefits, the other has no effect (+/0)

Question 23

Parasitism:

Answer 23

one organism benefits, the other is harmed (+/-)

Question 24

Amensalism:

Answer 24

one species is harmed, the other has no effect (-/0)