unit 3 evolution/biodiversity

What are the two major types of cells?

Prokaryotic (no nucleus, primitive; bacteria and archaea) and eukaryotic (has a nucleus and internal structures)

What is the most inclusive taxonomic level?

Domain

What are the levels of classification from most inclusive to least inclusive?

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

Why are scientific names important?

They are universal, avoid confusion, and are the only names scientists recognize

How do you properly write a scientific name?

Genus capitalized, species lowercase, both italicized (or underlined)

What is a species?

A group of organisms that can reproduce and produce fertile offspring

What is chemical evolution?

The formation of life’s basic chemical building blocks before life existed

What experiment showed small organic molecules could form on early Earth?

Stanley Miller experiment

What are the steps of chemical evolution?

Earth forms → small organic molecules → large organic molecules → protocells

What is biological evolution?

The development of living organisms from simple to complex over time

What were the first life forms on Earth?

Single-celled prokaryotes in the ocean

What organisms caused the oxygen revolution?

Photosynthetic bacteria (cyanobacteria)

Why was the oxygen revolution important?

It allowed ozone formation, oxygen-rich atmosphere, and life on land

What organisms formed after prokaryotes?

Unicellular eukaryotes, then multicellular eukaryotes

How do scientists know what life existed in the past?

Fossil record, radioactive dating, DNA, ice and mud cores

What is evolution?

A change in the genetic makeup of a population over successive generations

Where is genetic information stored?

DNA

What is a gene?

A sequence of DNA that codes for a trait

What is a gene pool?

All the genes in a population

What are alleles?

Different forms of the same gene

What is the key ingredient that allows evolution to occur?

Genetic variation

What is a mutation?

A random change in DNA

What causes mutations?

Mutagens such as chemicals and radiation

Are mutations common or beneficial?

Rare and usually harmful

What is gene flow?

Movement of genes between populations

What is natural selection?

When individuals with advantageous traits survive and reproduce more

What two things are required for natural selection?

Heredity and variation

What is differential reproduction?

Individuals with favorable traits produce more offspring

What is selective pressure?

Environmental condition that favors certain traits

What is an adaptation?

A beneficial inherited trait

What is directional selection?

One extreme trait is favored

What is stabilizing selection?

Average traits are favored; extremes eliminated

What is disruptive (diversifying) selection?

Extremes are favored; average eliminated

What is coevolution?

Two species evolving in response to each other

What is a habitat?

Where an organism lives

What is a niche?

The role or job of an organism

What is a fundamental niche?

The full potential role a species could occupy

What is a realized niche?

The role a species actually occupies due to competition

What is a generalist species?

Species with a broad niche (ex: raccoons)

What is a specialist species?

Species with a narrow niche (specific needs)

What is convergent evolution?

Different species evolve similar traits due to similar environments

Why is evolution not perfect?

Adaptations are limited by existing genes, trade-offs, reproduction limits, and competition

What is speciation?

One species splits into two new species

What usually causes speciation in animals?

Geographic isolation followed by reproductive isolation

What is extinction?

Permanent loss of a species

What percentage of all species that ever lived are extinct?

About 99.9%

What is background extinction?

Normal, ongoing extinction rate

What is mass extinction?

Rapid, widespread extinction of many species

What is adaptive radiation?

Rapid evolution of many species after extinction

What large-scale factors affect evolution and extinction?

Climate change, continental drift, meteor impacts

Why are island species unique?

Isolation and limited resources

Why are island species vulnerable?

Small populations, specialization, invasive species

What is artificial selection?

Humans breeding organisms for desired traits

What is domestication?

Long-term artificial selection reducing genetic diversity

What is genetic engineering?

Inserting genes from one species into another

What is a GMO?

Genetically modified organism

Why is genetic engineering controversial?

Changes DNA in ways that don’t occur naturally

What is biodiversity?

Variety of genes, species, ecosystems, and roles

Why is biodiversity important?

Increases ecosystem stability and resistance to disturbance

What goods and services does biodiversity provide?

Food, medicine, clean air, water, soil, pest control

What are anthropogenic causes of biodiversity loss?

Habitat destruction, invasive species, pollution, climate change, overexploitation

What is habitat fragmentation?

Large habitats broken into smaller isolated patches

Why is fragmentation harmful?

Increases edge effects and harms large predators

What causes habitat fragmentation?

Roads, agriculture, logging

What is one way to reduce biodiversity loss?

Criminalize poaching

What is sustainable land management?

Using land without degrading ecosystems

What is habitat restoration?

Repairing damaged ecosystems

What are wildlife corridors?

Land passages connecting habitats

What is CITES?

International treaty banning trade of endangered species

What does the Endangered Species Act do?

Protects endangered species and their habitats