Midterm 1 Flashcards
Endothermy
Ability to control body temp through internal metabolic processes and maintain homeostasis
Pokilothermy
organisms that have varible body temp and depend on outside factors to help regulate
Thermoregulation
ability to maintain a regular tissue temperature
4 means of heat transfer
Conduction - the direct transfer of heat between objects without the macroscopic motion of particles
convection - Heat transfer through fluid movements of substance
Evaporation - Heat dissipation
Thermal radiation - all animals emit infrared electromagnetic radiation that travels though the air and absorbs when it makes contact with something
Transient endothermy
maintain temp in certain part of their bodies that is generated by muscle contractions
- heat via constant movement
5 observations of natural selection
1: organisms have a great potential for fertility
2: natural population size doesn’t fluctuate
3: resources are limited
Infererence - struggle for existence
4: Variation occurs among individuals
5: variation is heriable
inference - find which possess traits favourable in competition in their environment will have differential survival
inference - over time population change with those possessing favourable characteristics
evolution
changes in genetic structure in populations over time
Genetic drift
change gene frequencies that happen randomly
Founder effect
loss of genetic variations when a new population is created - no selection
bottleneck
event that causes a decrease in population size
Gradualism
slow change over time
Allopatric population
two populations that become physically isolated that they become two separate populations
Sympatric
populations coexist together but are functionally seperate
morphology
understanding of the parts of an organism that:
shaped by internal/external factors
significance to these for functioning as a whole
limitations/possibilties these impose to evolution
Homologous structures
share a common ancestry but not necessarily the same function
- ex: 4 limb structures between humans and dolphins
Analogous structures
Share a similar function but not the same ancestral origin in the development
- ex; wings of bats and birds
Homoplastic structure
simply look alike but are not homologous or analogous
- ex: leaf bugs and actual leafs
Dispersal mechanisms
corridors
barrier
selective filter - some organisms can cross, some cant
sweepstakes - random event (bird in a hurricane)
Marsupials and evolution
are found in the areas that Eutheran (placental) mammals are not as present
- have many disadvantages that make them less likely to adapt to different climate
- but in Australia are abundant due to the amount of niches that were left unoccupied by mass extinction
4 eons
Hadean
Archean
Proterozoic
Phanerozoic - modern day
Mesozoic era
Age of the reptile
- largely cosisted of dinos, extinct reptile groups, and extant reptiles like turtles, alligators, snakes and lizards
Cenozoic
end of cretaceous, beginning of paleogene periods
- marked the loss of the dinos and other reptiles
- made room for mammals and birds to come in
Similarites between birds and reptiles
1: single occipital codyl (ball and socket joint)
2: single bone in the middle ear (stapes)
3: lower jaw made up of 5-6 bones
4: leg scales
5: Egg yolk polar development - yolk roates so embryo is always on top
6: hetergametic sex female - ZW (male ZZ)
7: nucleated red blood cells
8: Air sacs resemble chamelons and turtles
9: tetrachromatic vision (4 cones)
Archaeopteryx - ancient bird
both reptile and bird characteristics
Could Archaeopteryx fly?
may have been able to fly short distances by gliding but had to do it either top-down or bottom-up
top-down (jumping out of tree)
bottom-up (running)
Reptilian skull morphology
Anapsid: no post-orbital fenestra in jaw musculartur
Synapid: one post-orbital fenestra
Diapsid: rwo post-orbital fenestra
Parts of a feather
1: Rachis
2: Vane - surface
3: calamus/quill
4: lower (inferior) umbilicus - give blood supply to the feather
5: upper (superior) umbilius - growing part of feather
6: barb
7: Barbules
Types of feather
1: body contour - like flight but with symmetry
2: down
3: semiplume - like down but with barbs
4: bristle
5: Filoplume - act like a flag to help with change in weather
6: flight contour
Feather colours - Melanins
Produced by melanoblasts
two types:
- Eumelanins: grey, black, brown
- Phaeomelanins: reds, light browns, tan
Feather colours - Cartenoids
Bright yellows, reds, oranges, and certian blues
related to diet - the more healthy the more vibrant
Feather colours - Prophyrins
unique magenta, bright browns, and greens
light senstive
make the bird look almost metallic
Feather colours - structural
Both Iridescent and blues
- iridescent - layers with lightly packed melanins on barbs
- blue - single layer
Mammalian glands
Eccrine - sweat (not associated with hair follicle)
- help with cooling
Apocrine gland - sweat (associated with hair follicle)
Sebaceous - oily lubricant to lubricate the skin and hair
Mammary glands - milk
- Hair (platypus and ecidna)
- Teat - Milk collects in a cistern that has to be emptied
- nipple - stimulated by progesterone
Hair colour pattern
Warning
Disruptive
Countershading
Claws, horns, and nails
derived from keratinized cells from the secodary layer of the epidermis
- composed of a scaled unguis and attached to the pad of digit by the subunguis
Horns v antler
Horns: Grown from skull for duration of life
- both male and female have and don’t branch
Antlers: grow from boney progections of skull and shed annually
- grow velvet - shed to expose raw bone and more likely to branch
