bio 2 exam Flashcards
Biological species concept
members of the same species should be able to successfully mate with each other and produce fertile offspring
-Problems: It’s not practical to use since mating can be difficult to observe
-Does not apply to asexual species
Ecological species concept
members of a species should have similar diets, habitats, etc… (ecological niches)
-Not very easy concept to utilize without a lot of research
Phylogenetic species concept
members of a species should cluster together on the same branch of a phylogenetic tree
-Relatively easy and cheap to obtain and compare genetic sequences
-No assumptions about reproductive or ecological habits species do not have to have physical similarity
Speciation
evolution of a new species
-New species accumulate differences old species from combination of natural selection and genetic drift changing allele frequencies
Allopatry
each variety is its own range. Become species due to drift and local adaptation
Sympatry
Many varieties in one range. Become species through adaptation to different aspects of the range
Allopatric Speciation
Geographic barriers isolate populations of one species from each-other over time drift and selection make these different species
Sympatric speciation
speciation occurs within the population with no geographic barrier
-Could be caused by mutations created differences in things like mating or feeding behaviors
Adaptive radiation
A founding species can evolve into many new species if it is introduced into an environment where there are a lot of different resources to use or conditions to adapt to.
Polyploidy
when an individual has more than 2 chromosomes per homologous set
-Can cause speciation when some individuals in a population have more than the normal number of chromosomes
-Can happen due to errors in meiosis
Paedomophosis
when the juvenile stage of an organism becomes able to reproduce without completely transforming into the adult form.
- If these juveniles are different from adults in diet or habitat, they could become a new species
Symbiogenesis
2 different organisms fuse their cells or tissues together to form a new species.
Hox(Homeobox) Genes
control how structures develop along body segments
If these genes get moved around, duplicated, or get removed, they can cause major changes in body plan that can create new species.
Mitochondrial Dna
Clonal DNA lineage that is useful for tracking ancestry since it’s sequence does not get scrambled up each generation and it accumulates mutations slowly
(only inherited from the mother.)
Y chromosome DNA
Also useful for tracking ancestry: only inherited from father to son
Multiregional hypothesis
older hypothesis that humans are not one species and something like H.erectus evolved separately in different regions into modern human racial groups.
-No support based on current evidence
Bryophytes
mosses, liverworts, hornworts
-Most ancestral plants
-Life cycle is very similar to green algae
-Most are very small no tree forms (no vascular tissue)
Pterophytes
Ferns, club mosses, horsetails
-These plants emphasize the sporophyte life stage over the gametophyte
-Otherwise, life cycle is similar to bryophytes with swimming sperm and wind-dispersed spores
-Have vascular tissue for sugar and water transport
Gymosperm
cone-bearing plants
Angiosperm
flowering plants
- seeds dispersed using fruit
pollen
sperm contained in a hard capsule
seed
contains dormant sporophyte embryo with energy store
Anatomical Characteristics of Plants:
-Root-shoot body plan
-Look in notebook for drawing
vascular tissue
ties together root and shoot systems
-In larger plants ( shrubs and trees) it forms the wood and bark that support and protect the plant
Xylem function
-Pressure of water absorption in roots (root pressure)
-Adhesion and Cohesion of water molecules to each other and to xylem (capillary action)
-Evapotranspiration- water evaporates out through leaf pores (stomata)
xylem
water transport from roots to leaves
Phloem
Transport of sugars from leaves to other areas
Look in notebook for drawing
Phloem function
Dissolved sugars made in photosynthesis from high concentration to low concentration through phloem (diffusion)
gene
sequence of dna that codes for a phenoytipic trait
allele
varients of a gene
ex. of a gene
eye color
ex. of a allele
is Brown (B) or blue (b)
Homologous chromosome
Same gene but potentially different alleles
Evolutionary change
changes in allele frequencies in a gene in a population overtime (population genetics)
genetic drift
lowers change in allele frequencies through sampling error, or random change events where one allele is not more adaptive than another
genetic bottleneck
drift in which most of original population dies and survivors randomly have different allele frequencies compared to original population
founder effect
the type of drift when small genetically unrepresentative group founds a new isolated population
Morphological species concept:
members of a species have similar physical forms
- problems: some species mimic the appearance of others, and some species are really variable in appearance
Allele frequency
p+q=1
Genotype frequency
p^2+2pq + q^2=1
