3B4 Causes of Extinction Flashcards
Describe factors leading to species extinction, including genetic variation, competition, geological processes, and human actions.
What is extinction?
The death of all members of a species of plants, animals or other organisms on Earth.
What is mass extinction?
A significant and rapid loss of species on Earth during a short geological timeframe, with a rate of extinction far greater than the rate of speciation.
Some well known mass extinction events include:
- Permian extinction
- Ordovician-Silurian extinction
- Cretaceous-Tertiary (K-T) extinction
- End-Triassic extinction
- Devonian extinctions
What is the moment of extinction?
The point at which the last individual of a species dies.
Once the last individual of a species dies, the species is considered extinct.
How did the Dodo bird become extinct?
- Over-harvesting by humans.
- Introduction of invasive predator species.
- Habitat loss.
What is predicted to happen to extinction and biodiversity in the next 100 years?
Global biodiversity is expected to decline, with estimates suggesting that up to 54% of species may face extinction risks if current trends continue.
What is a major consequence of rapid climate change on species?
Forcing species to adapt to new climate patterns.
Some organisms successfully adapted while others did not. Examples:
- Flourishing of tree pests.
- Death of some coral species.
What was a major factor contributing to the extinction of the Carolina parakeet?
Overexploitation by hunting and fishing.
What are the main causes of extinction?
- Catastrophic events
- Diseases
- Predators
- Overexploitation
- Climate change
- Lack of genetic diversity
What are some catastrophic events that can cause extinction?
- Massive glaciation
- Meteors
- Various natural disasters
- Tectonic Plate Movement
- Volcanism
What are some major human causes of extinction?
- Overharvesting
- Pollution
- Habitat destruction
- Introduction of invasive species
- Overhunting
What is interspecific competition in ecology?
The battle between two species for the same resources in an ecosystem.
Examples:
- Woodpeckers and squirrels competing for nesting sights in trees.
- African savanna lions and cheetahs struggling for the same food.
What is the outcome of interspecific competition?
It frequently results in extinction for the less well-adapted species.
Define competitive exclusion.
Two species cannot persist in the same ecological habitat for an extended period without being pushed out due to competition for limited resources.
What are the three basic types of competition?
- Interference competition
- Exploitation competition
- Apparent competition
What is interference competition?
Direct interaction between species over a limited resource, involving aggressive seeking to exclude one individual from certain habitats.
What is exploitation competition?
An indirect interaction between species over a limited resource where one organism’s use of resources depletes the total amount available to another organism.
What is niche differentiation?
The process by which competing species exploit their environment differently in order to coexist.
Define fundamental niche.
A theoretical niche that reflects all ideal environments with no limiting factors or competition in which a species may survive.
Define realized niche.
Where the species actually live, reflecting the environments they inhabit.
What is the difference between fundamental niche and realized niche.
- Fundamental niche reflects all ideal environments where a species may survive.
- Realized niche is where the species actually live.
What are ecomorphs?
Populations of distantly related animals that have recently acquired morphological differences to adapt to certain environments.
What is the Competitive Lotka-Volterra Model?
A mathematical model formalizing the impacts of interspecific competition on populations.
