Animal Diversity - Taxonomy and Phylogeny of Animals

Phylogenetic Tree

Made with genetic data and often branches indicate evolutionary time

Nodes denote

Common ancestors

Tips denote

taxa

Root denotes

Beginning

The space between tips and branches mean…

NOTHING

What do the length between branches represent?

1. No meaning

2. Amount of evolutionary change

3. Time since common ancestry

In the cladogram shown below, Amphioxus is the __________.

Outgroup

The sister group of the gorilla is depicted here by which animal?

Rabbit

Based on the tree below, is the frog more closely related to the fish or the human?

Fish

Can nodes move?

Yes

Monophyletic

group includes most recent common ancestor and all descendants, synonymous with “clade”

Paraphyletic

includes most recent common ancestor and SOME descendants (not all)

Polyphyletic

group has at least 2 evolutionary origins

Phylogenetics

The study of species relationships and the use of genetic models to understand the probable history of life

Why is paraphyly important?

Establishes the direction of transmission, from which the source can then be inferred.

Parsimony

“other things being equal, a simpler explanation is better than a more complex one.”

Convergent evolution

Occurs when organisms that aren't closely related evolve similar features or behaviours, often as solutions to the same problems. Type of homoplasy

Homoplasy

A biological feature that is similar in different species but was not inherited from a common ancestor

Synapomorphies

a homologous trait that is shared among a clade and is distinctive to that clade.

Biological species concept

Cannot successfully interbreed

How do you write a species name?

Genus + species

Genus is always capitalized, species always lowercase. Both are typed in italics.

Population

potentially reproductively interactive group of animals of the same species

Populations of _____ species occur together in complex communities.

Many

Abiotic factors

include space, energy forms including sunlight, heat, wind and water currents, and the soil, air, water and chemicals (e.g. pH, elevation).

Biotic factors

Include other organisms as food, or competitors, predators, hosts or parasites.

Niche

includes the organism’s requirements for temp., moisture, food, etc.. Niches include other organisms

Generalists have ____ niches; Specialists have _____ niches

Wide; Narroq

For specialist, the fundamental and realized niches are very _____.

Similar

Interactions among organisms

• +, + mutualism

• +, 0 commensalism

• +, - predation, parasitism, herbivory

• -,- competition

• -, 0 amensalism