Test 1 Notes Flashcards
What makes it a bird?
Diagnostic Features
- feathers- present on all birds and NO other living creatures
- Furcula- fused clavioles
What makes it a bird?
Key Features
- keel
- bill
- wings
- bipedal locomotion
- no bony tail (pygostyle)
Increasing representation of more fit genotypes=evolution
Viola
Two key outcomes of evolution by natural selection
- adaptation
2. speciation
atonement to the environment
adaptation
may occur but doesn’t have to occur
speciation
changes within an environment
anagenisis
-adaptation
lineage splitting
cladogenesis
-speciation
- all of life evolved from a single common ancestor
- no TRANSITIONAL fossils
- got credit for wallices idea
Darwin
transitional fossil
intermediate between birds and dinosaurs
Archaeopteryx
150 million years old
jurassic perios
lived with familiar dinasours
was able to fly- assymetrical structure
Archaeopteryx
strongest argument
theory 2- birds predate dinosaurs
-based on the belief that the 3 digests retained in the bird wing differs from the dinosaurs
taxon with only one subgroup
ex/ ospray is the only species in family Pan
Monotypic taxon
a group comprising an ancestor and all desccendents
by definition monophyletic
clade
a hypothesis of evolutionary relationships of a group of organisms
phylogeny
2 broad methods for constructing phylogenies
- Phonetics
2. Cladistics
method for constructing phylogenies based on the overall similarity of the organisms
- total shared traits
- group organisms by similarity
Phonetics
methods for constructing phylogenies based on SHARED DERIVED CHARACTERISTICS
Cladistics
two ways species can have similar characteristics
- By decent-inherit trait from common ancestor
2. By convergence -independently
similar by decent
Homology
a character shared by a similar species but not in there ancestor
Homoplasy
old approach, played a big role in early molecular systematics
Phonetics
cadistic approach- the simplest phylogeny is the correct phylogeny
Principle of Parsimony
primary function of respiratory system
aquire O2
discard CO2
How do they reach O2 demands?
2 small dense lungs in thoracic cavity
no diaphragm
6-12 air sacs
birds core temp -40C
Thermoregulation
no additional energy required to maintain body temp
- upper critical limit
- lower critical limit
thermoneutral zone
must use energy to stay warm
lower critical limit
must use energy to stay cold
upper critical limit
2 requirements for high constant body temp
- insulation-feathers-best in nature
2. fuel- an unlimited supply
can reduce effectiveness or fitness as an insulator
artificial selection
heat generation
- biochemical breakdown of food
- cellular respiration - shivering
- rapid contraction and relaxation of skeletal muscles with no net movement
responses to cold
- adaptation, larger and darker colored
- erect feathers
- protected roost
- huddle
- shiver
skeletal anatomy
- fusion of bones
2. pneumatization of bones
flapping apparatus
pectorial major
supracoracoiclues
-both anchor at keel
challenge: how to raise the wing with muscle below it
powerful downstroak
pectorial major
upstroke
supracoracoiclues
why do northern birds move south in fall?
to avoid lack of food
avian thermoregulation
more feathers, more body fat
a slowing down of metabolic rate ( including drop in core temp) during part of daily cycle
Torpor
-Many hummingbirds use this
slowing down of metabolic cycle for part of anual cycle
Hibernation
used for food storage
crop
chemical digestion
proventricles
mechanical digestion
grizzard
small stones swallowd and stored in grizzard
grit
site of bacterial digestion
ceacum
all birds are____ in sex chromosomes
diploid
hapliod sex chromosomes
gametes
diploid cell resulting from combination of egg & sperm chromosomes
zygote
Males and females contribute 50% of _____ genes via sexual reproduction
nuclear
_____ engage in recombination
autosomes
- no recombination
- very high mutation rate
- codes for essential respiratory genes
mitochondrial genome
female sex chromosomes
ZW heterogametic
male sex chromosome
ZZ homogametic
reproduction in which eggs are laid by the female and develop outside of the body
-all birds
oviparous
the eggs produced by a bird in a continuous laying bout
clutch
egg is coated with
- Albumen
- Shell membrane
- Shell pigment
produce sperm (haploid)
testes
transport and stores sperm
Vas Deren
adds nutrients to produce semen
seminal vesicle
a common reproductive strategy i birds with copulatory organs
forced copulation
