Chapter 16

Radiometric dating

Method used to determine the age of rocks using the rate of decay of radioactive isotopes

Radioactive Isotope

An isotope whose nucleus decays spontaneously, giving off particles and energy.

Half life

Length of time required for half of the radioactive atoms in a sample to decay

Sedimentary rock

A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together

Igneous Rock

A type of rock that forms from the cooling of molten rock at or below the surface

During a radioactive decay event, an unstable isotope emits one or more ________

Particles or rays

Radioactive elements continue to decay until they reach a _______ __________

Stable isotope (or stable nucleus)

How can radioactive decay be used to determine the age of a rock sample?

By comparing the ratio of parent isotopes (radioactive atoms) to daughter isotopes (stable atoms) within a rock sample.

Place the organisms in the list in the correct order from earliest appearance to least appearance:

fungi

flowering plants

grasses

seedless plants

cone-bearing plants

soft-bodied invertebrates

mammals

reptiles

insects

coral species

Soft-bodied invertebrates → Coral species → Fungi → Seedless plants → Insects → Cone-bearing plants → Reptiles → Mammals → Flowering plants → Grasses

How can you tell when a rock is older, if it has more unstable elements or more stable elements when it decays

You can tell a rock is older if it has more stable elements and fewer unstable (radioactive) elements.

Adaptive radiation

Evolution from a common ancestor of many species adapted to diverse environments

Biogeography

Study of past and present distribution of organisms

Continental Drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

Plate tectonics

A theory stating that the earth's surface is broken into plates that move.

Extinction vs Mass Extinction

Extinction = One species disappears

Mass Extinction = Huge number of species disappear at once

How does adaptive radiation affect species distribution?

Increases biodiversity and distributes species across different ecological niches

Convergent Evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

Taxonomy

The scientific study of how living things are classified

Vertebrates

Animals with backbones

Mammals

Animals that have hair and produce milk for their young

Phylogeny

Evolutionary history of a species

Phylogenetic Tree

A family tree that shows the evolutionary relationships thought to exist among groups of organisms

Domain

A taxonomic category above the kingdom level. The three domains are Archaea, Bacteria, and Eukarya.

How many species are currently described on Earth?

1.5 - 2 million species

What kinds of features do taxonomists use to classify organisms into groups?

Structural Features

Functional Features

Behavioral Features

Genetic and Molecular Features

Evolutionary Relationships

What is the order of taxonomy?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Why did scientist need DNA evidence to resolve the relationships among these groups?

DNA evidence allows scientists to trace true evolutionary relationships at the molecular level

In a phylogenetic tree what does a node represent?

Most recent common ancestor shared by the lineages branching from that point