BIOL 1P92 Introduction to Biology II EXAM help
notes for you 2025-2026 Brock University
Bio EXAM
BEFORE MIDTERM
- What is evolution
o The notion that species change over time
o Early views believed that life was unchanging, but this did not account or explain
fossils
o It explains how
▪ Underlying common features that organisms possess
▪ How species continue to change over time in response
to environmental changes
- Micro vs macro
o Micro- no new species made in the process but virus/bacterial changes (sma
o Macro- changes that are so big that new species are created
- Evolutionary mechanisms
o Mutations, non-random mating, gene flow, genetic drift, natural selection
o Random and to chance change, may get a subpopulation
from the original population
▪ Can go from a lot of variability to very little
▪ Genetic drift is not selective
o In Hardy Weinberg equilibrium no change
▪ If met, no changes occur
▪ If not in equilibrium microevolutions occur
o Agents of microevolution
▪ Gene flow / migration
• Allows movement of alleles across populations
▪ Genetic drift
• Random change in alleles frequencies
• Important in small pops
• Reduces genetic variability
, • FOUNDER EFFECT
o Due to individuals starting a new pop
• BOTTLE NECK
o Reduction in alleles due to population reduction
▪ Mutations
• Change in double stranded sequence in DNA
• Spontaneous heritable changes
• Significant over long term
• RECALL; substitution, insertion, deletion, inversion, duplication
- Natural selections
o Directional
▪ Favours traits on one side of pop
o Stabilizing
▪ Favours intermediate traits
o Disruptive
, ▪ Favours extreme traits
- Phylogenetic relationships
o Monophyletic clades
▪ Includes 1 ancestral species and all its descendants
o Polyphyletic
▪ Includes species from separate lineages
o Paraphyletic
▪ Contain an ancestor and some of its descendants
- 3 domains of life
o Archaea, bacteria, eukaryote
▪ Eukaryotes vs. Prokaryotes
• Eukaryotes
o Nucleus present
o Membrane-bound nucleus
o More than 1 number of chromosomes
• Prokaryotes
o Nucleus absent
o 1 chromosome is present
o Not true chromosome plastid
-
- Speciation mechanism
o Allopatric
▪ when 2 pops separated for so long that they change and
are no longer able to breed
▪ Physical barrier subdivides a large pop
▪ Species cluster- a group of closely related species
(founder effect and genetic drift)
▪ Hybrid zone- secondary contract
• Area between 2 similar species which set the species apart
• Zones of “overlapping” “supercolliders” of speciation
o Sympatric
▪ Adaptation to local environments
• Diverge and occupy local environment that are similar
▪ Polyploidy
• 2 or more sets of chromosomes (can occur through
non-disjunction “autoploidy”
• Plants more tolerant
▪ Sexual selection
• When females are picky
- Biological species concepts
o What is a species?
o 2 individuals if they can sexually reproduce and have viable
offspring, they are the same species
o Groups of interbreeding natural pops that are reproductively isolated
notes for you 2025-2026 Brock University
Bio EXAM
BEFORE MIDTERM
- What is evolution
o The notion that species change over time
o Early views believed that life was unchanging, but this did not account or explain
fossils
o It explains how
▪ Underlying common features that organisms possess
▪ How species continue to change over time in response
to environmental changes
- Micro vs macro
o Micro- no new species made in the process but virus/bacterial changes (sma
o Macro- changes that are so big that new species are created
- Evolutionary mechanisms
o Mutations, non-random mating, gene flow, genetic drift, natural selection
o Random and to chance change, may get a subpopulation
from the original population
▪ Can go from a lot of variability to very little
▪ Genetic drift is not selective
o In Hardy Weinberg equilibrium no change
▪ If met, no changes occur
▪ If not in equilibrium microevolutions occur
o Agents of microevolution
▪ Gene flow / migration
• Allows movement of alleles across populations
▪ Genetic drift
• Random change in alleles frequencies
• Important in small pops
• Reduces genetic variability
, • FOUNDER EFFECT
o Due to individuals starting a new pop
• BOTTLE NECK
o Reduction in alleles due to population reduction
▪ Mutations
• Change in double stranded sequence in DNA
• Spontaneous heritable changes
• Significant over long term
• RECALL; substitution, insertion, deletion, inversion, duplication
- Natural selections
o Directional
▪ Favours traits on one side of pop
o Stabilizing
▪ Favours intermediate traits
o Disruptive
, ▪ Favours extreme traits
- Phylogenetic relationships
o Monophyletic clades
▪ Includes 1 ancestral species and all its descendants
o Polyphyletic
▪ Includes species from separate lineages
o Paraphyletic
▪ Contain an ancestor and some of its descendants
- 3 domains of life
o Archaea, bacteria, eukaryote
▪ Eukaryotes vs. Prokaryotes
• Eukaryotes
o Nucleus present
o Membrane-bound nucleus
o More than 1 number of chromosomes
• Prokaryotes
o Nucleus absent
o 1 chromosome is present
o Not true chromosome plastid
-
- Speciation mechanism
o Allopatric
▪ when 2 pops separated for so long that they change and
are no longer able to breed
▪ Physical barrier subdivides a large pop
▪ Species cluster- a group of closely related species
(founder effect and genetic drift)
▪ Hybrid zone- secondary contract
• Area between 2 similar species which set the species apart
• Zones of “overlapping” “supercolliders” of speciation
o Sympatric
▪ Adaptation to local environments
• Diverge and occupy local environment that are similar
▪ Polyploidy
• 2 or more sets of chromosomes (can occur through
non-disjunction “autoploidy”
• Plants more tolerant
▪ Sexual selection
• When females are picky
- Biological species concepts
o What is a species?
o 2 individuals if they can sexually reproduce and have viable
offspring, they are the same species
o Groups of interbreeding natural pops that are reproductively isolated
