Exam 2
What is the difference between mono-, para- and polyphyletic?
Monophyletic- a clade Paraphyletic- part of a clade Polyphyletic- more than one clade
What is a homologous structure? An analogous one?
A homologous structure is a shared in multiple species because of common ancestry. An analogous structure is the same basic structure found in various species because of convergent evolution.
What is the endosperm?
A tissue rich in nutrients that nourishes the gametophyte- it has a 3n chromosome number because of double fertilization
What is tropism?
Any growth response that causes a plant to grow towards or away from stilmuli.
What roles does auxin play in a plant?
cell elongation, apical dominance, leaf abscission
What role does gibberellin play in a plant?
fruit development and seed germination
What role do cytokinins play in a plant?
induce cell division and plant group, control apical dominance
What role does ethylene play in a plant?
monitors all plant stresses, programmed cell death, and leaf abscission
What role does abscisic acid play in a plant?
seed dormancy, drought tolerance
What are the prezygotic barriers that would prevent reproductive success between 2 organisms?
1. Habitat- they live in different environments 2. Temporal- they mate at different times of day or different times of the year 3. Behavioral- they have different courtship patterns 4. Mechanical- structure of genitalia prevents successful reproduction 5. Gametic- the sperm does not survive once inside the female
What 2 main principles guide the development of plants?
1. Positional information: the position/location of a cell determines the type of cell it will be, it is often determined by polarity 2. pattern formation: specific structures develop in specific locations
What are the postzygotic barriers that distinguish between different species?
1. Reduced Hybrid Viability- the hybrid dies does not survive development 2. Reduced Hybrid Fertility- the hybrid is sterile 3. Hybrid Breakdown- the offspring of the hybrid are sterile
What are 2 main differences in the lifecycles of mosses and ferns?
1. The sporophyte is dominant in ferns, while the gametophyte is dominant in mosses 2. The sporophyte of a moss is nutritionally dependent on the gametophyte, while the sporophyte and gametophyte of a fern are independent of one another.
What is the advantage of having seeds as a means for reproduction?
1. seed coat provides protection 2. provide a supply of food 3. can remain dormant for periods of time 4. able to withstand harsh conditions and far transport
What were some of the constraints organisms had to face when moving onto land? What adaptations evolved to address these constraints?
1. surface area to volume ratio- transport systems carry nutrients through organism 2. gravity- structural support of cells 3. aridity- water conservation and change in fertilization 4. nutrient uptake- systems of nutrient exchange and consumption evolved 5. salinity- developed filtering system
What advantages do seed plants have?
1. the gametophyte develops in the sporangia, which provides protection and nutrients 2. seeds are better able to survive harsh conditions, and can go dormant 3. pollen allows for airborne transport for fertilization, which means 2 plants can reproduce from a further distance 4. fruits and flowers aid in seed dispersal
What were the main advantages for plants becoming terrestrial?
1. unfiltered sunlight 2. nutrient-rich soil 3. abundant CO₂ in atmosphere 4. relatively few herbivores/pathogens at first
What's the difference between gradualism and punctuated equilibrium?
Both refer to the evolution of species over time. However gradualism states that evolution occurred slowly, over a long period of time. Punctuated equilibrium occurs when there are periods of apparent stasis interrupted by sudden change.
What is the hierarchy of classification?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
What is the hierarchy of classification for humans?
Eukarya, Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, Sapiens
What is sympatry? How might it occur?
Sympatry is the evolution of species without a physical barrier. It can occur through sexual selection, polyploidy, and habitat differentiation.
What is the difference between the apoplastic and symplastic route? What is the name of the barrier blocking the apoplastic route?
The apoplastic route allows water and nutrients to move along cell walls. The symplastic route moves through the cytoplasm. The Casparian strip blocks the apoplastic route, which allows for more effective filtering of molecules entering the xylem.
What is allopatry?
The evolution of a species due to a physical barrier.
What is the concept of parsimony?
The simplest possible explanation for the evolution of a species or group of species is the one that occurred- used to make cladograms.
