BIOLOGY 4TH QUARTER

PRECAMBRIAN

the "Age of Early Life". During the Precambrian, continents formed and our modern atmosphere developed, while early life evolved and flourished. Soft-bodied creatures like worms and jellyfish lived in the world's oceans, but the land remained barren.

Period

denotes an event that necessarily does not have any specific time frame for that to have happened

Epoch

An extended period of time usually characterized by a distinctive development or by memorable series of events.

Era

suggests a period of history marked by a new or distinct order of things.

Eon

It describes a part of Earth's existence lasting hundreds of millions to billions of years

Hadean Eon

Named after the Greek God and ruler of the underworld Hades, is the oldest eon and dates from 4.0-4.5 billion years ago. This time represents Earth's earliest history, during which the planet was characterized by a partially molten surface, volcanism, and asteroid impacts.

Proterozoic Eon

modern plate tectonics became active, and the ancient cores of the continents moved over wide areas of the globe, accumulating smaller fragments of crust and sometimes colliding with other large landmasses

Archean Eon

Is a geologic eon, 4000-2500 million years ago (4 - 2.5 billion years ago), that followed the Hadean Eon and preceded the Proterozoic Eon. During the Archean Eon, the Earth's crust cooled enough that rocks and continental plates began to form.

Cambrian

Explosion of life.

All existing phyla come into being at this time.

Life forms in warm seas as oxygen levels rise enough to support life.

Dominant animals: Marine invertebrates

(trilobites and brachiopods).

Supercontinent Gondwana forms near the South Pole (note position of present-day Florida)

Paleozoic Era

Major interval of geologic time that began 538.8 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end -Permian extinction, the greatest extinction event in Earth history.

Phanerozoic Eon

is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 541 million years to the present and began with the Cambrian Period when animals first developed hard shells preserved in the fossil record.

Ordovician

-is the second period of the Paleozoic Era.

- lasted about 45 million years and saw the transition from very primitive to relatively modern life-forms in the seas. The "Ordovician radiation" which followed the late Cambrian extinctions, lead to a tripling of marine diversity, the greatest increase in the history of life, and giving the highest levels of diversity seen during the Paleozoic Era.

Silurian

First land plants appear and land animals follow.

Laurentia collides with Baltica and closes lapetus Sea.

Coral reefs expand and land plants begin to colonize barren land.

First millipede fossils and sea scorpions (Euryptides) found in this period

Devonian (Age of Fish)

Pre-Pangea forms. Dominant animal: fish

Oceans still freshwater and fish migrate from southern hemisphere to North America.

Present-day Arctic Canada was at the equator and hardwoods began to grow.

Amphibians, evergreens and ferns appear.

The Acadian Orogeny, leading to S.C. metamorphism

Pennsylvanian

Modern North America begins to form.

Ice covers the southern hemisphere and coal swamps formed along equator.

Lizards and winged insects first appear.

Mississippian

First seed plants appear.

Much of North America is covered by shallow seas and sea life flourishes (bryozoa, brachipods, blastoids)

Mesozoic Era

Second of Earth's three major geologic eras of Phanerozoic time.

Its name is derived from the Greek term for "middle life." The Mesozoic Era began 252.2 million years ago

The major divisions of the Mesozoic Era are, from oldest to youngest, the Triassic Period, the Jurassic Period, and the Cretaceous Period.

The ancestors of major plant and animal groups that exist today first appeared during the Mesozoic

Permian

Last period of the Paleozoic

Pangea forms. Reptiles spread across continents.

The Appalachians rise

90% of Earth's species become extinct due to volcanism in Siberia. This marks the end of trilobites, ammonoids, blastoids, and most fish.

Cretaceous

T-Rex develops

First snakes and primates appear

Deciduous trees and grasses common

First flowering plants

Mass extinction marks the end of the Mesozoic Era, with the demise of dinosaurs and 25% of all marine life.

Jurassic

Pangea still breaking apart

Dinosaurs flourish "Golden age of dinosaurs"

First birds appear

North America continues to rotate away from Africa

Triassic

First dinosaurs appear

First mammals- small rodents appear

Life and fauna re-diversify

Rocky Mountains form.

First turtle fossil from this period

Pangea breaks apart

Tertiary

First horses appear and tropical plants dominate (Paleocene)

Grasses spread and whales, rhinos, elephants and other large mammals develop. Sea level rises and limestone

deposits form in S.C. (Eocene)

Dogs, cats, and apes appear (Oligocene)

Horses, mastadons, camels, and tigers roam free in S.C. (Miocene)

Hominids develop and the Grand Canyon forms (Pliocene)

Cenozoic Era

Third of the major eras of Earth's history, beginning about 66 million years ago and extending to the present.

The Cenozoic Era is generally divided into three periods: the Paleogene (66 million to 23 million years ago), the Neogene (23 million to 2.6 million years ago), and the Quaternary (2.6 million years ago to the present); however, the era has been traditionally divided into the Tertiary and Quaternary periods.

Quarternary

Modern humans develop and ice sheets are predominant- Ice age

(Pleistocene)

Holocene Humans flourish (Holocene)

Prokaryotes (single-celled organisms)

Archean eon and onwards

Animals, plants, fungi

Paleozoic era and onwards

Dinosaurs

Mesozoic

Mammals, birds, humans

Cenozoic

Natural Selection

Is the process that results in adaptation of a population to the environment.

Adaptation

enables beneficial mutations to be passed on to the next generation.

These beneficial mutations are called

Artificial Selection

Human-driven process of identifying and breeding organisms with desirable traits such as increased size, speed, or specific colors to enhance those characteristics in future generations

Mutation

Provides new alleles, and therefore are the ultimate source of variation.

Is a change in the DNA nucleotide sequence of an allele.

May not immediately affect the phenotype.

Can be beneficial, neutral, or harmful.

Recombination

It involves the breaking and rejoining of DNA strands, usually between homologous chromosomes (maternal and paternal) during meiosis 1.

Gene Flow

The migration of the gene from one population into another.

Continued gene flow decreases diversity among population, causing gene pools to become similar

Genetic Drift

In each generation, some individuals may, just by chance, leave behind a few more descendants (and genes) than other individuals. The genes of the next generation will be the genes of the "lucky" individuals, not necessarily the healthier or "better" individuals

HOMOLOGOUS STRUCTURES

Features shared by different species due to a common ancestors.

Example: forelimbs of humans, whales, and birds.

ANALOGOUS STRUCTURES

Similarities that evolved independently due to similar environments, not shared ancestry.

Example: Egg-laying in ducks vs. platypuses.

EMBRYOLOGY

Early developmental stages often reveal ancestral links not visible in adult forms

GENETIC CODE

All living things share the same basic DNA and gene expression (transcription/translation).

MOLECULAR HOMOLOGY

The more similar the DNA sequences in homologous genes, the more closely related the species is.

GEL ELECTROPHORESIS

A tool used to compare DNA fragments.

Identical bands positions shared DNA sequences.

More shared bands = closer evolutionary relationship.

Taxonomy

Came from Greek word "taxis" meaning "arrangement" and "nomia" meaning "distribution or method"

the science of organizing and categorizing living organisms into classes called taxa

deals with the identification & naming (nomenclature) of organisms; began with ancient Greeks & Romans

Systematics

the study of the diversification of life forms over time, both past and present, and their relationships between other species

Nomenclature

the orderly application of binomial names to a particular taxon (taxonomic group)

Identification

recognition of certain distinguishing characters of the plant specimens; results in the comparison of the specimen with similar specimen

Classification

arrangement of plants into groups having common characteristics; results in the placing of plants into a hierarchy of ranks or categories.

Carl Von Linne

Born in May 1707 in Southern Sweden received medical degree in 1735 from University of Harderwijk in Netherlands

"Father of Modern Taxonomy" published several books and papers including Systema Naturae, Fundamenta Botanica, and Genera Plantarum classified plants based on number, arrangement and length of stamens

Archaea (bacteria-like organisms)

any group of single-celled prokaryotic organisms that have distinct molecular characteristics separating them from bacteria as well as eukaryotes

Bacteria (true bacteria)

a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some that can cause disease.

Eukarya (protists, fungi, plants and animals)

any of a domain (Eukarya) or a higher taxonomic group (Eukaryota) above the kingdom that includes organisms composed of one or more cells containing visibly evident nuclei and organelles.

Haplontic

having a life cycle in which the main form of the organism is haploid (n), meaning it has a single set of chromosomes. The only diploid stage is the zygote, which is formed briefly after fertilization.

Diplontic

having a life cycle in which the main form of the organism is diploid (2n), meaning it has two sets of chromosomes. The haploid stage is represented only by the gametes

Phylogeny

Representing evolutionary history through “tree diagrams”

Cladistics

A method of grouping organisms by common ancestry. Established by the scientist Willi Hennig in the 1950s.