Exam Two Flashcards
assortative mating
phenotypically similar individuals mate: increases proportion of homozygous individuals
disassortative mating
phenotypically different individuals mate: this produces excess of heterozygotes
genetic drift
variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce
founder effect
the reduction in genomic variability that occurs when a small group of individuals becomes separated from a larger population
bottleneck effect
an extreme example of genetic drift that happens when the size of a population is severely reduced
ex: natural disaster
what can genetic drift lead to
loss of alleles in isolated populations
tenets of natural selection
individuals in a population show variation in traits, variable traits must be heritable, individuals must have unequal survival and reproductive successes
what does natural selection act on
individuals
difference between evolution and natural selection
natural selection is a process, while evolution is the historical record or outcome of change through time
what was the evidence of natural selection
Darwin noticed variations in related species living in different locations
fossil evidence
plants and fungi arrived on land before animals
role of plants
supply oxygen and food terrestrial animals
roles of fungi
breaks down organic material and recycles nutrients
origin of land plants
all green algae and land plants shared a common ancestor approximately 470 million years ago
what are the two major clades of green algae
chlorophytes and charophytes
chlorophytes
never made it to land
charophytes
sister to all land plants
sporopollenin
durable polymer that prevents zygotes from drying out
apical meristems
localized regions of the cell division at the tips of roots and shoots; capable of cell division throughout the plants allowing elongation of roots and shoots
sporophyte
multicellular diploid stage
- produces haploid spores by meiosis
- diploid spore mother cells (sporocytes) undergo meiosis in sporangia
gametopyte
multicellular haploid stage
- spores divide by mitosis
- produces gametes by mitosis
- gametes fuse to form diploid zygote
examples of variations in AOG
moss: a non-vascular plant
- large gametophyte
- small dependent sporophyte
angiosperm: seed plant
- small dependent gametophyte
- large sporophyte
mycology
study of fungi, approximately 80k fungal species, most are multicellular, some are single-celled, both asexual and sexual reproduction
heterotrophic
most are saprobes, some are parasitic, most recent common ancestor of animal and fungi 460 million years ago
hyphae
multicellular fungi consist of long slender filaments
what flows through hyphae
cytoplasm; which allows for rapid growth under good conditions
mycelium
mass of connected hyphae; it grows through and digests its substrate
what do fungal cell walls include
chitin
mycorrhizae
key adaptation to life on land
monokaryotic
one nucleus
dikaryotic
2 nuclei within each hyphal cell but are not fused
where can gene flow take place
can take place between two populations of the same species, can take place between two different species, within a population, between genetically distant populations, can be facilitated by the physical proximity of populations, but gene flow can equally be restricted by physical barriers separating populations
when can non random mating occur
occurs when probability that two individuals will mate is not the same for all possible pairs of individuals
what are the two forms of non random mating
inbreeding and outbreeding
Wahlund effect
-Difference between the overall non-random mating of positive and negative phenotypic assortment
-Apparent excess in homozygotes and deficit of heterozygotes from what is expected if a population were to mate randomly
-WE is a common cause of non-confirmative to HWE
- Inbreeding causes a population to depart from HWE
-HWE is an assumption of no evolutionary change present
-Anything that leads to evolutionary change whether positive or negative change is still a departure from no change
zombie virus
viruses that are currently encased by permafrost and now pose as a risk to reinfect humans due to climate change
embryophytes
A clade of land plants that include, but is not limited to:
Liverworts, mosses, hornworts, and vascular plants
what do “barren” lands include
“Barren” lands include desserts, polar plains, alpine rocks
formula for photosynthesis
Light + H2O + CO2 = photosynthesis
Green plants + Chlorophyte Algae
Ch 1a
Ch 1b
Starch
Other Algae (kelps, diatoms)
Chl a
Chl b
Carbs – lipids
Red Algae
Only Chl a
Green Algae
Like land plants have life cycles with gametophyte and sporophyte generation
Chl a
Chl b
Beta carotene
Xanthophyll
Some green algae have cell walls made of cellulose
what three groups is green algae categorized into
unicellular and colonial algae, Algal cells, charophytes
unicellular and colonial algae
Volvox- characterized in the family Volvocaceae, thrive in a variety of freshwater habitats, unicellular but colonial
algal cells
Multicellular and form flat layer of single cells
Produce unicellular gametophyte stage
charophytes
Multicellular with thick branching filaments
Have a cell plate during mitosis that we see in higher plants
Have sporopollenin which prevents zygotes from drying out
what challenges did algae ancestors face
drought, heat, life stress, alter atmospheric oxygen levels, and pathogens
why do we say alternation of generations
because all plants have the diploid and haploid phase in their lifecycle
what does the sporophyte represent
the period between fertilization and meiosis which produces the spores
heteromorphic
If the sporophyte and gametophyte forms have very different appearances
isomorphic
If the sporophyte and gametophyte form and are less identical
meristem
a group of multipotent cells that can differentiate into a specialized cell, have regenerative properties and can self organize
what are the two types of meristem
the upper ground shoot apical meristem and the below ground root meristem
what does the shoot apical meristem produce
leaves and stems
geotrophic
in the direction of gravity
phototrophic
in the direction of light
before differentiation how do meristematic cells divide
Meristematic cells divide by mitosis before differentiation
is shoot meristem geotropic or phototrophic
Shoot meristem is negatively geotropic and positively phototropic
psudeohypahe
psudeohypahe are chains of elongated ellipsoidal cells with a constriction between them; they are the most common invasive fungal pathogens in humans
Filamentous mold
multicellular
chitin
Chitin is an amino polysaccharide
fungi
are eukaryotic multicellular organisms composed of filaments that are called hyphae; their cells are long and thread like and are connected end to end
mycelium
The whole body of any fungus is called the mycelium
when reproductive hyphae are produced, they form a large organized structure called
sporocarp or mushroom
glucan and mannan are
saccharides
Ectomycorrhizae
associates with roots externally while arbuscular mycorrhizae also known as endomycorrhizal form finely branched hyphae within the cells of the plant root
Many fungi are saprotrophs (saprobes) meaning
they live off of dead or decaying organic matter
Zygomycota, basidiomycata, and Ascomycota are without
flagella
what is the second most abundant polysaccharide after cellulose
Chitin
- It is a rigid crystallized polymer that is insoluble in water
- About three to twenty-five percent of fungal body mass consists of chitin on a dry weight basis
