Chapter 4 Flashcards
(99 cards)
When all members of a species die
Extinction
the pace at which species go extinct due to gradually changing environments.
Most extinctions occur as part of this.
Background extinction rate
Earth has witnessed five ___________ in the last 600 million years. During these periods, many species went extinct in a short time.
mass extinctions
suggests that meteorites or comets caused some mass extinctions.
The debris suspended in the atmosphere after a collision dramatically changed the environment, leading to the extinction of many species.
Impact theory
(Earth’s shifting land masses) also might explain mass extinctions.
Plate tectonics
= early life
= age of dinosaurs
= era of mammals
Paleozoic
Mesozoic
Cenozoic
= the cretaceous (K) – tertiary (T) boundary
The KT boundary
A layer of sediment containing high levels of iridium
The K-T boundary
the study of interactions between biotic and abiotic elements
Ecology
All living components
Biotic
Nonliving elements
• temperature, light, water, minerals, air
Abiotic
A group of organisms inhabiting the same area
Population
:an individual living thing
Organism
: the study of how populations interact and change in response to their environment
Population ecology
: the study of organismal adaptations that allow it to live in its environment
Organismal ecology
: interacting populations that inhabit a particular area
Community
: the study of population interactions and how these dynamics affect community structure
Community ecology
: the nonliving environment and all the living organisms within a certain area
Ecosystem
: the study of energy flow and nutrient cycling in a given environment
Ecosystem ecology
: the global ecosystem
– All of the ecosystems on the planet
– Most complex level in the ecological hierarchy • Atmosphere down to the deepest ocean depths
Biosphere
– Immediate responses to environmental changes – May be behavioral or physical
– Short term and quickly altered
Thermoregulation
– Longer term responses
– Reversible
– Includes thicker fur in winter (winter coat), increased or decreased metabolism, increased fat stores, etc.
Acclimation
: the way individuals are spaced within a geographic range
Patterns of dispersal
: individuals aggregated in patches
Clumped