Biology II Final Exam: Material from Exam II

Fitness

ability to survive + reproduce

Trait

heritable characteristic determined by genes

Phenotype

physical expression of traits

Adaptation

trait that increases fitness in a specific environment

Mutation

change in DNA that creates new traits

Biological species concept

species = interbreeding group producing fertile offspring

Allopatric speciation

speciation due to geographic isolation

Prezygotic barrier

prevents mating/fertilization

Postzygotic barrier

prevents hybrid viability/fertility

Sexual selection

traits evolve to increase mating success

Define fitness

ability to survive + reproduce; linked to genes, traits, phenotype

Define adaptation

heritable trait that increases fitness

Three conditions for natural selection

variation; heritability; differential survival/reproduction

Acclimation vs adaptation

acclimation = short‑term, non‑genetic; adaptation = long‑term, genetic

Role of mutation

source of new traits and variation

Define biological species concept

interbreeding group producing fertile offspring

Describe allopatric speciation

geographic isolation → independent evolution → reproductive isolation

Prezygotic vs postzygotic barriers

before fertilization vs after fertilization

Role of sexual selection

traits evolve to improve mating success

Phylogenetic tree

hypothesis of evolutionary relationships

Node

most recent common ancestor

Branch point

speciation event

Sister taxa

closest relatives

Monophyletic group

ancestor + all descendants

Paraphyletic group

ancestor + some descendants

Polyphyletic group

unrelated taxa grouped incorrectly

Homology

similarity due to shared ancestry

Analogy

similarity due to convergent evolution

Convergent evolution

independent evolution of similar traits

Homoplasy

similarity not due to ancestry

Parsimony

simplest tree with fewest evolutionary changes

How does a phylogenetic tree represent history?

branching pattern shows hypothesized relationships

How do trees + Linnean hierarchy group species?

both group by relatedness

What do nodes represent?

most recent common ancestors

How do branching points relate to speciation?

represent reproductive isolation events

Homology vs analogy

ancestry vs function

How are homologies used in trees?

shared traits map relationships

What is parsimony?

choose tree with fewest evolutionary changes

Domain Bacteria

prokaryotes; outgroup to Archaea + Eukarya

Domain Archaea

prokaryotes; closest to Eukarya

Photoautotroph

energy from light; carbon from CO₂

Photoheterotroph

energy from light; carbon from organics

Chemoautotroph

energy from chemicals; carbon from CO₂

Chemoheterotroph

energy from chemicals; carbon from organics

Conjugation

DNA transfer via direct contact

Transformation

DNA uptake from environment

Transduction

DNA transfer via bacteriophage

Domain Eukarya

organisms with nucleus + organelles

Protists

eukaryotes that are not plants, animals, fungi

Endosymbiosis

origin of mitochondria/chloroplasts from engulfed bacteria

Kingdom Fungi

eukaryotic absorptive heterotrophs

Ascomycota

sac fungi producing spores in asci

Basidiomycota

club fungi producing spores on basidia

Hyphae

fungal filaments for absorption

Lichen

fungus + algae/cyanobacteria

Mycorrhizae

fungus + plant roots

Metazoa

all animals

Eumetazoa

animals with true tissues

Bilaterians

bilateral symmetry + 3 germ layers

Deuterostomes

anus develops first

Chordates

animals with notochord, dorsal nerve cord, pharyngeal slits, post‑anal tail

Vertebrates

chordates with backbone

Amniotes

vertebrates with amniotic egg

Mammals

hair + mammary glands

Monotremes

egg‑laying mammals

Marsupials

pouch mammals

Eutherians

placental mammals

Primates

mammalian order including humans

Bony fishes

fish with bony skeleton

Lobe‑finned fishes

fleshy fins; tetrapod ancestors

Amphibians

vertebrates with metamorphosis + moist skin

Which domain is closest to Eukarya?

Archaea

Which domain is the outgroup?

Bacteria

Energy/carbon sources of prokaryotes?

photoautotroph, photoheterotroph, chemoautotroph, chemoheterotroph

Define transformation

DNA uptake from environment

Are protists eukaryotic?

yes

Role of endosymbiosis

origin of mitochondria + chloroplasts

Are fungi closer to plants or animals?

animals

Nutritional mode of fungi

absorptive heterotrophy

Role of hyphae

absorption, growth, reproduction

Why are fungi important?

decomposition, symbiosis, nutrient cycling

Lichens composed of

fungus + algae/cyanobacteria

Mycorrhizae composed of

fungus + plant roots

Where did notochord appear?

chordates

Where did vertebrae appear?

vertebrates

Where did jaws appear?

gnathostomes

Where did lobed fins appear?

lobe‑finned fishes

Where did limbs with digits appear?

tetrapods

Where did amniotic egg appear?

amniotes

Four chordate traits

notochord, dorsal hollow nerve cord, pharyngeal slits, post‑anal tail

Characteristics of amphibians

moist skin, metamorphosis, eggs in water, 3‑chambered heart

Why amniotes succeeded on land?

amniotic egg, waterproof skin, efficient kidneys