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