Unit 3 Exam

Radiometric Dating

a method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes

Half-Life

the time required for 50% of a radioactive isotope to decay

Stromatolites

layered rocks that form when certain prokaryotes bind thin films of sediment together

Endosymbiosis

a symbiotic relationship where one organism lives inside the other

(Ex: a prokaryote cell engulfed a small cell that would evolve into an organelle found in all eukaryotes)

Serial Endosymbiosis

a theory that supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events

Cambrian Explosion

the time (in geological history) when most of the major groups of animals first appear in the fossil record

(called "explosion" because the relatively short time for this diversity to appear)

Prior to the Cambrian explosion, all large animals were ___________ __________ and appear to have been grazers, filter feeders, and scavengers. The explosion changed all of this.

soft-bodied

Plate Tectonics

a theory that the continents are part of great plates of Earth's crust that essentially float on the hot, underlying portion of the mantle

Continental Drift

movements in the mantle cause the plates to move over time (very slowly)

(promotes/causes Allopatric speciation)

Pangaea

the supercontinent that formed near the end of the Palezonic era, when plate movements brought all the landmasses on Earth together

(drove some species to extinction and allowed others to thrive)

Mass Extinction

a large number of species become extinct worldwide (result of global environmental changes)

Permian Mass Extinction

(claimed about 96% of marine animal species) Volcanism and lava resulted in extreme amounts of Co2 and warming, which led to ocean acidification

Cretaceous Mass Extinction

occured 65 million years ago, killing 78% of all species (including dinosoars). Caused by an asteroid hitting the Earth.

(the large amounts of sediment in the atmosphere blocked the sun and caused a long period of global freeze)

Adaptive Radiation

periods of evolutionary changes in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles, or niches, in their communities.

Ex: Darwins finches of the Galapagos Islands

Exaptation

a trait or structure of a taxonomic group that takes on a function that never previously existed (derived by evolution)

Ex: the use of feathers for mating displays or flight (feathers originally evolved to keep warm)

How many mass extinctions have been documented over the past 500 million years?

5 mass extinctions have been documented

Evolution works by ________________ with existing structures

Evolution works by "tinkering" with existing structures

Phylogeny

the evolutionary history of a species of group of related species

Systematics

a discipline focused on classifying organisms and determining their evolutionary relationship

To avoid confusion when communicating about their research, biologists refer to organisms by __________ ____________ names.

Latin Scientific

Binomial

(latinized format for naming species) consisting of the genes and specific epithet

Ex: Apis mellifera (Honey Bee)

Genus

a taxonomic category above the species level (the first word of a binomial)

Ex: Apis mellifera --> [Apis]

Linnaean System

living organisms are classified into groups depending on their structure and characteristics

Taxon

the named group at any level of the hierarchy

Ex: for a leopard, 'Panthera' is a taxon at the genus level and Mammalia is at the class level

Phylogenetic Tree

a branching diagram that represents the evolutionary history of a group of organisms

Branch Point

represents a common ancestor of the two evolutionary lineages diverging from it

Evolutionary Lineage

a sequence of ancestral organisms leading to a particular descendent taxon

Sister Taxa

groups of organisms that share an immediate common ancestor that is not shared by any other group

Ex: chimps and humans

Rooted

means that a branch point within the tree represents the most recent common ancestor of all taxa in the tree

Basal Taxon

a lineage that diverges from all other members of its group early in the history of the group

Homologies

similarity in characteristics resulting from a shared ancestry

Analogy

similarity between two species that is due to convergent evolution (rather than common ancestor)

occurs when similar environmental pressures and natural selection produce similar adaptations from different evolutionary lineages

Cladistics

an approach to systematics in which organisms are placed into groups called clades based primarily on common descent

groups that include an ancestral species and all of its descendants

A group of species that includes an ancestral species and all its descendants

Ex: Mammalia, Aves (birds), angiosperms, insects

Monophyletic

taxa that consists of a common ancestor and all of its descendents

Paraphyletic

taxa that consists of a common ancestor and some but not all of its descendents

Polyphyletic

taxa that includes distantly related organisms but does not include their most recent common ancestor

Shared Ancestral Character

a character that originated in an ancestor of the taxon

Ex: hair is a character shared by all mammals but not found in their ancestors

Shared Derived Character

an evolutionary novelty that is unique to a particular clade

(a character in a species that has changed since the species descended from its past ancestors)

Outgroup

a species or group of species from an evolutionary lineage that is closely related to but not part of the species being studied

Ex: outgroup -> Gibbons (20 species of apes)

Ingroup

a species or group of species whose evolutionary relationships are examined in a given analysis

Ex: ingroup -> Great Apes

In phylogenetic trees, the length of branches do not indicate the degree of __________________ _____________ in each lineage.

Evolutionary Lineage

(instead proportional to the times at which each particular event occurred)

Maximum Possibility

one should first investigate the simplest explanation that is consistent with the facts

Maximum Likelihood

when considering multiple phylogenetic hypotheses, evaluates that the choosen evolutionary model will have generated the observed sequences

What are the 5 biological kingdoms?

Monera (prokaryotes)
Protista (mostly unicellular organisms)
Plantae
Fungi
Animalia

Horizontal Gene Transfer

when genes are transfered from one genome to another (such as exchange of transposable elements)

Ex: when a host and its endosymbiont become a single organisms

Eukaryotes can acquire genes by _______________ ____________ ________ from prokaryotes.

Horizontal Gene Transfer

Yeast

unicellular fungi that live in damp places and can reproduce by budding (eukaryotic and asexual)

Hyphae

one of many connected filaments that collectively make up the mycellium of fungus

Chitin

a strong but flexible polysaccharide (chitin-rich walls can enhance feeding my absorbtion)

Septa

one of the cross walls that divide a fungal hyphae into cells

Coenocytic Fungi

a fungus that lacks septa and whose body is made of cytoplasmic mass

Mycelium

mass of hyphae

Members of domain _________ have a nucleus and other membrane bound organelles

Eukarya

What are the two main types of body structure?

single cells (yeasts) and multicellular filaments

Mycorrhizae

a mutualism between fungi and plant roots

Ectomycorrhizal

a symbiotic fungus that forms hyphae over plant roots

Arbuscules

specialized branching hyphae that penetrate plant cells for extraction or exchange of nutrients

(parasitic and mutalistic fungi)

What are the 4 types of fungi?

free-living, parasitic, mutualistic, and carnivorous

Spores are ___________

haploid

Spores can survive poor environmental conditions through _____________

Dormancy

Asexual reproduction is entirely ___________ ; uses mitosis

haploid

Molds

a fungus that grows as a filamentous fungi that produce spores by mitosis

Yeast are single celled and reproduce through ______________

budding

Cryptomycetes

unicellular fungi that have flaggelated spores

Microsporidan

unicellular parasites of protists and animals

(have a small genome and lack flagella)

Chytrids

mostly aquatic fungi with flagellated zoospores

(mostly unicellular; some form colonies with hyphae)

Zoopagomycetes

multicellular parasites or commensal symbionts of animals

(includes a fungus that attacks insects and turns them into "zombies")

Mucoromycetes

Black Bread Mold (fast growing mold)

(contain arbuscular forming groups) - important in lichens and mycorrhizal networks of plants

Ascomycetes

commonly called sac fungus

(have a symbiotic relationship with cynobacteria and other plants)

Basidomycetes

"Club Fungi" - includes most familiar fungi such as rust, mushrooms, and shelf fungi.

(only sexual reproduction)

Arbuscular Mycorrhizal Fungus

a symbiont fungus whose hyphae grow through plant roots and into the root cell

Spores

in Fungi, a haploid cell, produced sexually or asexually that produces mycellium after germination

(produced in the sporophyte by meiosis)

Plasmogamy

fusion of cytoplasm of cells (cells from 2 individuals)

Karyogamy

fusion of haploid nuclei contributed by two parents

Heterokaryon

A fungal mycelium that contains two or more haploid nuclei per cell.

Dikaryotic

a fungal mycellium with two haploid nuclei per cell (one from each parent)

The sexual processes of karyogamy and meiosis "generate extensive ______________ ______________"

Genetic Variation

Deuteromycete

traditional classification for a fungus with no known sexual stage

Sporopollenin

a durable polymer that prevents exposed zygotes from drying out

Cuticle

a covering for a plant made of wax and other polymers which provides protection

What does a Cuticle help do?

helps as waterproofing and prevents extensive water loss (desiccation)

Stomata

the small openings on the undersides of most leaves that allows gas exchange in and out of the plant

Vascular Tissue

cells joined into tubes that transport water and nutrients throughout the body

Liverworts, mosses, and hornworts don't have ____________ tissue

vascular

Bryophyte

an informal name for a moss, liverwort, or any non-vascular plant that lives on land

Lycophytes

club mosses and their relatives

Monilophytes

ferns and their relatives

Gymnosperms

a vascular plant that bears naked seeds

Angiosperms

A flowering plant which forms seeds inside a protective chamber called an ovary.

Microphylls

a small (spine shape leaf) supported by a singular strand of vascular tissue (found only in lycophytes)

Megaphylls

leaves with highly branches vascular system

What are the two types of vascular tissue?

xylem and phloem

Xylem

conducts the water and minerals

Phloem

cells arranged into tubes that distribute sugars, amino acids, and other organic products

Homospores

Plants that produce one type of spore

Heterospores

a plant species that has 2 types of spores
(microspores and megaspores)

Megaspore

spores that develop into female gametophytes

Microspore

smaller spores that develop into male gametophytes

Integument

layer of sporophyte tissue that envelops and protects an ovule of a seed plant

Gymnosperms - one integument
Angiosperms - two integuments