Skip to main content
Back

ch.25

Control buttons has been changed to "navigation" mode.
1/29

Terms in this set (29)

  • How did eukaryotic cells evolve from prokaryotic cells?
    Eukaryotic cells evolved through endosymbiosis, where a prokaryotic cell engulfed another, forming organelles like mitochondria and chloroplasts as endosymbionts.
  • What are biases of the fossil record?
    The fossil record is biased toward organisms with hard parts, those living in environments favoring fossilization, and more recent species, causing incomplete preservation.
  • What are the main steps necessary for the evolution of life on Earth?
    Key steps include formation of protocells, development of self-replicating molecules like ribozymes, and emergence of cellular life in oceans.
  • What is the approximate age of the Earth?
    The Earth is about 4.5 billion years old.
  • When did prokaryotes first appear?
    Prokaryotes appeared roughly 3.5 to 4 billion years ago.
  • When did eukaryotes first appear?
    Eukaryotes appeared about 1.5 to 2 billion years ago.
  • When did multicellular eukaryotes appear?
    Multicellular eukaryotes appeared around 1 billion years ago.
  • When did animals first appear?
    Animals appeared approximately 600 million years ago.
  • When did land plants first appear?
    Land plants appeared about 470 million years ago.
  • When did humans first appear?
    Humans appeared roughly 200,000 to 300,000 years ago.
  • How has Earth's environment changed over its history?
    Earth's environment changed from a hot, volcanic atmosphere to oxygen-rich air, with major events like ice ages and mass extinctions affecting life.
  • How do major environmental changes affect living organisms?
    Environmental changes drive evolution by creating new selection pressures, causing extinctions, and enabling adaptive radiations.
  • How can the age of a fossil be estimated using radiometric dating?
    Radiometric dating measures decay of radioactive isotopes to calculate absolute fossil age.
  • How does fossil depth in sedimentary rock relate to species age?
    Deeper fossils are generally older, providing a relative timeline of species existence.
  • Where did the first living cells evolve?
    The first living cells evolved in the oceans.
  • How does spatial gene expression affect pattern formation?
    Spatial gene expression controls where and when genes activate, shaping organism development and body patterns.
  • Why does early development help understand evolutionary relationships?
    Similarities in early development reveal common ancestry and evolutionary links among species.
  • Why is evolution not goal-oriented?
    Evolution lacks a predetermined direction; it results from natural selection acting on random variation.
  • Define protocells.
    Protocells are simple, membrane-bound structures that exhibit some life-like properties, precursors to true cells.
  • What are hydrothermal vents?
    Hydrothermal vents are underwater fissures emitting hot, mineral-rich water, possibly sites for origin of life.
  • What are alkaline vents?
    Alkaline vents are underwater vents with high pH, proposed as environments for early biochemical reactions.
  • What are ribozymes?
    Ribozymes are RNA molecules with catalytic activity, capable of self-replication and biochemical reactions.
  • What is an endosymbiont?
    An endosymbiont is an organism living inside another, such as mitochondria inside eukaryotic cells.
  • What was the Cambrian explosion?
    The Cambrian explosion was a rapid diversification of animal life about 540 million years ago.
  • Define unicellular and multicellular organisms.
    Unicellular organisms consist of a single cell; multicellular organisms have many specialized cells.
  • What is a prokaryote?
    A prokaryote is a single-celled organism without a nucleus or membrane-bound organelles.
  • What is a eukaryote?
    A eukaryote is an organism with cells containing a nucleus and membrane-bound organelles.
  • What is adaptive radiation?
    Adaptive radiation is rapid evolution of diverse species from a common ancestor in response to new environments.
  • What is half-life in radiometric dating?
    Half-life is the time it takes for half of a radioactive isotope to decay, used to date fossils.