Biology Final Exam: Key Concepts in Biodiversity, Evolution, and Conservation

What is biodiversity?

The number, variety, and variability of species in a given area.

How is biodiversity commonly measured?

By the number of species present in an area.

What defines a species?

A group of organisms able to reproduce with one another.

What is a biodiversity hotspot?

A biogeographic region with high biodiversity that is at risk of destruction.

What is the lowest level of biological organization?

Organism - one individual living thing.

What is a population in biological terms?

Members of the same species living in the same area.

Define community in ecology.

All populations/species living together in an area.

What is an ecosystem?

A community plus the nonliving environment.

What is background extinction?

Natural, ongoing, low-level extinction of species.

What characterizes mass extinction?

Occurs very rapidly and affects many ecosystems globally.

What was the Permian mass extinction?

The largest mass extinction, resulting in about a 95% extinction rate.

What caused the Permian extinction?

Volcanic activity and rapid climate change.

What happened at the end of the Ordovician period?

Over 50% of marine species went extinct.

What was significant about the end of the Devonian period?

About 50% of animal species on land and in seas were wiped out.

What occurred at the end of the Permian period?

Largest extinction; up to 95% of species were lost.

What happened at the end of the Triassic period?

Eliminated about 48% of existing animal species.

What was the impact of the Cretaceous extinction?

Eliminated the last dinosaurs and many reptiles, allowing mammals to rise.

What is a major cause of modern biodiversity loss?

Climate change, habitat destruction, invasive species, overexploitation, and pollution.

How does climate change affect biodiversity?

Increased CO2 from fossil fuel burning changes Earth's temperatures.

What is habitat destruction?

When habitats become patchy, degraded, or unusable for native species.

What are invasive species?

Non-native species that spread rapidly and displace native species.

What is overexploitation?

Humans remove organisms faster than populations can replace them.

What is pollution in the context of biodiversity?

A substance introduced into the environment that harms health or reproduction.

What are rainforests known for?

Being the most diverse and productive terrestrial ecosystems, covering about 6% of Earth's surface.

What is the significance of coral reefs?

They are the most diverse ecosystem on Earth, providing habitat for over 4,000 marine species.

What role do zoos play in conservation?

They protect, rehabilitate, and breed endangered species.

What are wildlife corridors?

Paths that allow safe movement between isolated habitats without human interference.

What is speciation?

The formation of new species, often due to isolation or different resource use.

What is prezygotic isolation?

Prevents fertilization before a zygote forms.

What is postzygotic isolation?

Occurs after fertilization or after a zygote forms.

What does a phylogenetic tree visualize?

Evolutionary pathways and connections among organisms.

What do nodes in a phylogenetic tree represent?

Common ancestors.

Which two domains are thought to be more closely related: Archaea, Eukarya, or Bacteria?

Archaea and Eukarya.

What major event occurred during the Cambrian period?

A large and sudden increase in animal diversity.

What significant development occurred in the Ordovician period?

Jawless fishes appeared and plants began colonizing land.

What characterized the Devonian period?

Increase in land plants, seed plants, insects, and amphibians.

What was a key trait of the Carboniferous period?

Coniferous forests and the dominance of amphibians.

What significant event marked the end of the Permian period?

A mass extinction event.

What major groups of organisms appeared during the Triassic period?

The first dinosaurs and mammals.

What significant developments occurred during the Jurassic period?

Dinosaurs diversified, and the first birds and flowering plants appeared.

What is the significance of the Tertiary period?

Diversification of flowering plants, birds, mammals, and pollinating insects.

What major evolutionary event occurred in the Quaternary period?

The evolution and age of modern humans.

What are the two key events needed for the first cells to evolve?

Formation of the plasma membrane and genetic material.

What does the endosymbiotic theory explain?

How mitochondria and chloroplasts became part of eukaryotic cells.

What is the Opisthokonta supergroup?

Includes fungi, choanoflagellates, and animals.

What defines nonvascular plants?

Require water for reproduction and lack true roots, stems, and leaves.

What is a key trait of vascular plants?

Have xylem and phloem, and possess roots, leaves, and stems.

What distinguishes angiosperms?

They are flowering plants that attract pollinators and provide nourishment.

Why were fungi moved from plants to Opisthokonta?

DNA evidence shows fungi are more closely related to animals.

What is a defining characteristic of all animals?

They are multicellular and ingest their food.

What major animal body plans were established?

About 500 million years ago.

What is the extinction rate during the Permian extinction?

95% extinction rate.

What is the biggest threat to biodiversity?

Habitat destruction.

What is the current geological age dominated by human activity called?

Anthropocene.

What type of isolation occurs before fertilization?

Prezygotic isolation.

What type of isolation occurs when offspring are weak or sterile?

Postzygotic isolation.

What phylum includes flatworms?

Platyhelminthes.

What fish group includes rays?

Cartilaginous fish.