EXAM 1 Study Deck Flashcards
What is Darwin’s theory of Descent with Modification
Darwin’s theory is that different species share characteristics because they evolved from a single ancestor.
descent with modification
Individuals do no evolve, but populations evolve over time. Depending on an individuals relative fitness some will reproduce more than others causing…….
Accumulation of favorable characteristics in a population over time.
unequal ability to survive and reproduce means accumulation of favorable traits over generations.
descent with modification
If more young are born than can survive then…
they will compete for limited resources.
What three things are required for Natural Selection?
1)
2)
3)
1) Individuals must vary in characteristics
2) Traits must be heredible
3) Individuals must differ in relative fitness in a particular environment.
Where does variation come from?
1) sexual reproduction
2) error during meiosis
3) mutation
4) gene duplication
5) Gene flow
Define a phenotype
A phenotype is a physical expression of a gene.
Why cant selection produce perfect adaptions?
Because selection can only use what is already provided. It cannot CREATE variation.
Environment and relative fitness determines which individuals survive and pass down characteristics.
What is meant by the Agent of Selection
Relative fitness depends on the environment, the same phenotype may have differing fitness in certain environments.
Define Genetic Drift
Genetic drift is the random fluctuations in allele frequency, randomly eliminating genotypes and decreasing variation.
In large populations this balances out, not so much in smaller ones.
The Bottleneck effect
The bottleneck effect is when a population decreases dramatically. As result of genetic drift
The Founder effect
A large population arises from a small one. Leads to limited diversity and low ability to respond to environmental change, fixation of allele (bad if negative ones).
What forces keep variation despite genetic drift.
sources of variation
Mutations-neutral or positive
Sex (recombination)-horizontal gene transfer
Crossing over/independent assortment
Gene duplication
Gene Flow-mitigation in/out of population
How does speciation happen?
1)
2)
1) Gene flow must be interrupted between populations of the same species.
2) Populations diverge sufficiently becoming reproductively isolated
Allopatric Speciation
Populations become physically isolated geographically. by mountains, rivers, distance, islands.
Sympatric Speciation
subpopulations share the same location but become reproductively isolated because they access new food supplied, go to different regions or interbreed with others.
Define Species
Species are reproductively isolated from others. No hybrids thanks to isolating mechanisms.
Isolating mechanisms preventing hybrids form forming: PRE-ZYGOTIC
Habitat/Temporal/Behavioral isolation
Prevents fertilization in the first place
Individuals don’t recognize or come into contact with each other. Mating rituals don’t match up/mate at different times.
Isolating mechanisms preventing hybrids form forming: PRE-ZYGOTIC
Mechanical Isolation
Prevents fertilization in the first place
“Lock and Key don’t fit”
Sperm cant reach eggs, mating unsuccessful
Isolating mechanisms preventing hybrids form forming: PRE-ZYGOTIC
Gametic Isolation
Prevents fertilization in the first place
Sperm reaches eggs, but fertilization doesn’t occur.
Isolating mechanisms preventing hybrids form forming: POST-ZYGOTIC
Hybrids dont survive
Hybrids have low viability and fertility
Most common. Inivitable
Isolating mechanisms preventing hybrids form forming: POST-ZYGOTIC
Hybrids are Sterile
Hybrids have low viability and fertility
Reduced hybrid fertility
Isolating mechanisms preventing hybrids form forming: POST-ZYGOTIC
Hybrids have low fitness
Hybrids have low viability and fertility
They may be viable or fertile but their offspring may be sterile or have low reproductive success of survival.
What is Upwelling and how does it occur
Upwelling is when lower level waters, colder but filled with nutrients, come up to the surface. Usually as a result of strong offshore winds. Breaks up the Thermocline layers. It introduces more nutrients to the surface helping growth of organisms and brings more species in for food.
Coriolis effect
Air moves clock-wise in the northern hemisphere and counter-clock-wise in the southern hemisphere.
Air currents are the result of the coriolis effect and rising warm water.
Thermoclines
The colder (denser) waters of the ocean are beneath the warmer surface waters
Haloclines
The saltier and more nutrient rich (denser) materials are in the lower water levels, while less on the top surface levels.
Colder water also holds more oxygen than warm surface waters.
Primary productivity is the lower level creatures in the food chain reproducing and growing, providing food for the higher level creatures.
What affects Primary productivity?
Primary productivity can be limited by nutrients such as Nitrogen and Phosphorous.
Aquatic productivity is limited by light-half absorbed on the surface, only 5-10% reaches 75%lower levels
What is El Nino and how does it affect primary productivity?
EL Nino is when air pressure decreases in the eastern pacific, allowing warm water to flow eastward.
This decreases upwelling, limiting primary productivity
Tropic levels
The tropic levels are the levels of the food web
Primary producers(phototrophs)=> Primary consumers(herbivores)=>Secondary consumers(carnivores)
Define foodchain
the food chain is the transfer of energy between the different trophic levels.
How many links can be made in the trophic level
limited to 5 links at most
trophic interactions
Bottom-Up
biomass at lower levels affect higher levels
nutrients-producers-primary consumers-secondary consumer
trophic interactions
Top-Down
higher trophic level limits abundance of lower trophic level
-many species feed at multiple trophic levels
sec consumer-primary-producers-nutrients
biomass
combines mass of all individuals
food web
food chains all linked together-complex trophic interaction
common prey species for marine birds and mammals
phytoplankton-algae,cyanobacteria,diatoms,dinoflagellates
(primary producer)
zoo plankton- copepods, fish larva, eggs(Primary consumer)
fish- anchovy,sardine,herring,rockfish,salmon,capelin (Secondary consumer)
interspecies competition
competition for resources with a different species
intraspecies competition
competition for resources with their same species
What is an ecological niche
an ecological niche is how species use abiotic and biotic resources in an environment. Two species cannot share the same ecological niche without competition.
How to avoid competition for ecological niche
a species can avoid competition if they evolve a different way to use their set of resources, or use them in a different way or a different time.
Predator characteristics
specialized teeth/weaponry
acute senses
camoflage
Prey characteristics
safety in numbers
structures for protection (like spikes)
Camouflage
Chemicals/toxins
life history
life history are the traits that affect a species survival and schedule of reproduction
FOUR main factors of Life History 1) 2) 3) 4)
1) age of first reproduction
2) how often reproduction occurs
3) how many offspring are produced each time
4) amount of parental care investment on offspring
R-Selected parental behavior
semelparous
a parent gives limited parental care. They produce many small, short-lived offspring that reproduce quite quickly and a lot.
Best for disturbed of unpredictable habitats
K-Selected parental behavior
iteroparous
a parent gives a lot of parental care and raises them for a number of years. They produce few, but larger offspring that delay in reproduction.
Best for stable habitats
Sexual Dimorphism
males and females differ in appearance and/or behavior
intersexual selection
mate has choice-one sex chooses based on particular traits-showy ornamentation, bizzare behavior
intrasexual selection
same sex competition-individuals of the same sex compete for a mate-weaponry and intimidation, set up fight territories.
mating system
Polygamous
one sex mates with multiple others-favored when offspring require little to no parental care.
polygynous-male w. many females
polyanderous-female with many males
mating system
Promiscuous
both sexes mate with multiple partners
mating system
monogamous
one male with one female
Male mating strategies
female defense-defend large group of females
resource defense-defending territory or useful resources
self-advertisement-show self in areas with lots of females
sneaking-fertilizing eggs when not looking
Female mating strategies
direct benefits- look for a male that gives resources
good genes- look for a male based on quality
male choice copying- female wants what other wants
Inclusive fitness
inclusive fitness is the ability to pass on genes to the next generation
kin selection
kin selection is favoritism of reproductive success of individuals relatives. Spreads as results of inclusive fitness.
direct fitness
fitness of ones self and offspring
indirect fitness
fitness of relatives besides self and offspring
alturism
risking ones own survival to help others with best reproductive success.
tit or tat-why help non-related individuals? Treat others way you were treated before.
Hamilton’s rule relationship*Benefit>Cost
cooperative breeding
other females help other raise child
Costs to living in groups 1) 2) 3) 4) 5)
1) spread of disease
2) attracts predator
3) competition for food
4) harder to find habitat
5) competition for mates
Benefits to living in groups 1) 2) 3) 4) 5) 6)
1) increase alturism
2) increase shared parental care
3) dilution effect against predator
4) hold down territory better
5) more diversity
6) more mating options
sign stimulus
sign stimulus is an external cue that triggers behavior.
fixed action pattern
sequence of unlearned actions
super-normal stimuli
exaggerated signal which leads to a more intense response
innate behavior
behavior that the individual is born with, basic instincts are all basically the same. developmentally fixed
learned behavior
behavior that the individual learns from others, is taught growing up
critical period
the finite period during early development where an individual learns what they hear.
classical conditioning
part of associative learning-individual has no control over outcome-most common in nature.
operant conditioning
part of associative learning-gives individuals some control-behavior associated with reward or punishment-training
negative reinforcement
taking away positive options as result of behavior
punishment
something bad happens because of behavior
observational learning
learning from observing others
spatial learning
observing landscape and creating mental map of area, good for memorizing where stored food.
culture
part of observational learning, information transfer through social learning and teaching that influences behavior of individuals and fitness. culture evolves over time.
why signals not direct action?
sometimes a direct action (such as a snake biting with venom) can be “expensive”. Avoid conflict without having to actually fight. chemical signals mark territory. attract mate.
ways animals percieve signals 1) 2) 3) 4)
1) visual-light flashes, movement, color
2) hearing
3) tactile-feeling
4) smell/taste-chemoreceptors
ways animals send signals 1) 2) 3) 4)
1) light flashes, movement, color
2) auditory-vibration to create sound
3) touching each other
4) olfactory-chemical signals (pheremones)
Sound waves
sound is vibration of molecules colliding with each other propagated as longitudinal wave. air=340m/sec, water=1500m/sec, ground=5000m/sec. Transmitted through vibrations of the vocal tract-
light waves
Light shines in different wavelengths. light hits an object and all colors are absorbed except one that is reflected-we see it as that color. That light hits the retinas so we can see. hits pigments and rods
Broad band signals
a vocal signal that covers a wide range of frequencies
Narrow range signals
vocal signals that cover a narrow range.
Fundamental frequency
the lowest component of frequency when we vocalize
harmonics
frequency components that occur at multiples of fundamental, contain certain info
attenuation
attenuation is where sound decreases in amptitude as it travels from the source. Signals become distorted as waves bounce off surfaces or objects in environment-thats why many species use low frequencies
Pigments
pigments are substances in the eyes that absorb different wavelengths of light. What is not absorbed is reflected. pigments called melanin’s reflect brown and black. Carotenoids reflect red, orange and yellow.
pigment
Melanin
reflect brown and black.
pigment
Carotenoids
Carotenoids reflect red, orange and yellow.
Larynx
sound producing in mammals and amphibians
Syrinx
sound producer in birds
