Avian Biology Exam 1

What does natural selection lead to?

Adaptations

Artificial selection

Selection performed by humans

Sexual selection

Selection from preference of sex. May be intersexual or intrasexual.

Intersexual selection

Mate attraction (opposite sex)

Intrasexual

Competition (same sex)

Sexual dimorphism

When males and females look different (common when no mutual parental care)

Reverse sexual dimorphism

Male provides more care for the female

The handicap principle

a hypothesis that explains how costly signals can be reliable and honest

Runaway selection

A hypothesis that explains the development of elaborate traits. E.g. very very red individuals

Genetic dissimilarity

Choosing mates that are more different

Genetic compatibility

Gives the benefit of more immunity and avoiding incompatibility.

Social monogamy

Breeding as a couple

Allopatric isolation

Geographic isolation. Includes: population split, colonization, ring species

Sympatric speciation

when a new species evolves from an existing species while both species live in the same area. Non-geographic isolation. Includes temporal/allochronic speciation, differences due to food specialization and host species as well.

Barrier formation

A barrier forms that separates populations

Colonization

One group moves far away (e.g. overseas)

Ring species

A species that moves around, and by the time they meet again and are a completely different species

Allochronic/temporal speciation

a shift in the timing of their life cycle events (like breeding seasons)

Ecological speciation

Natural selection leads to adaptation to different environments (e.g.one breeds in tall grass prairies, one breeds in short grass prairies). Not allopatric or sympatric

Reproductive isolation

The inability to interbreed even when together (not example of non-geographic isolation)

Hybridization

• After time in isolation, different species meet and can breed and create a hybrid species

Partial reproductive isolation

Hybrids are rare or less fertile, can create a hybrid zone (where hybrids can be found, but more narrow geographic area)

No reproductive isolation

Two groups mix and become indistinguishable

AdvancedHybridization

an interbreed but don’t have viable offspring

Complete hybridization

Hybrids won’t exist

Reinforcement

• a selection pressure that give the species more differences, and thus their prezygotic barrier will not allow for unviable offspring to even be produced

What is a species concept?

A set of criteria assigned to a species status

Monophyletic group

A clade. Has the most recent common ancestor shared.

Binomial nomenclature

How scientific names for species work

Speciation

One species gradually splits into two or more species

Taxon

A group of organisms recognized in a classification (a branch/ family/genus/species)

Systematics

Includes classification and phylogenetic relationships

Classification

How organisms are organized in taxonomy

Phylogenetic relationships

Phylogeny

Sister taxa

2 groups that are each others closest relatives

Snapomorphies

Shared characteristics. E.g. feathers

Convergent evolution

Traits that evolve multiple times (eg bird wings and bat wings)

What is our biogeographic realm?

Nearctic

Wallace’s line

Famous foe separating indo-malay-australasia. Describes how islands were never connected.

What is the group of birds?

Theropod dinosaurs!

What traits are characteristic to theropod dinosaurs?

Feathers and pneumatized bones. Wishbone, small genome, bipedal, fast growing young, eggs, nesting

Archaeopteryx lithographica

The oldest known bird. Lived over 150 million years ago in the jurassic period.

Paleognanthae

Flightless birds:

Struthioniformes- ostriches

Nepgnanthae

Flying birds:

Gallanoseres- fowls

Galliformes- landfowels

Anseriformes- waterfowl

Neoaves- all other birds

Tail

Steering (long straight)

Wing

Flight (long, curved)

Semiplume

Insulation (some fluffy scattered around base)

Contor

Insulation, coloration, protection, aerodynamics. Half colored half downy

Down

Insulation

Filoplume

Sensation

Bristle

Protection

Pennaceous

Smooth firm part of feathers. Have hooks on barbules for interlocking.

Plumaceous

Downy part of feather