Evolution Flashcards
Evolution
the process by which organisms have changed over time from simple, single-celled organisms to multicellular, complex organisms.
Natural Selection
Nature selects those individuals who are best fit for the environment.
Overproduction
more offspring are produced than can survive
Competition
The fight for limited resources
Variation
Differences among organisms in a species (sexually reproducing organisms have more variation than asexually reproducing organisms)
Extinction
The disappearance of an entire species caused by a failure to adapt to a changing environment. Extinction occurs when the Environment changes and the Species cannot adapt.
Ecology
The study of how organisms interact with the living and nonliving things
Biotic factors:
Living parts of the ecosystem. Example: Plants and animals.
Abiotic factors:
non-living parts of the environment (rocks, air, pH, sunlight
Niche
A species’ role in it’s environment (it’s JOB and what it EATS)
Population
All the organisms of a species that live in the same area.
Community
All the different populations in an area.
Biosphere:
All of earth’s ecosystems
Competition
The struggle for resources among organisms
Limiting Factors
Are the living and non living things in the environment that limit the size of populations.
Examples: Food, Shelter, Sun, Space, Oxygen, ETC.
Carrying Capacity
the maximum population (number of organisms of any species) that an ecosystem can support.
Predators
Kill and eat other organisms called Prey
(Feeding Relationships)
Autotrophs
(producers) make their own food by photosynthesis
(Feeding Relationships)
Heterotrophs
must eat something for food (consumers)
(Feeding Relationships)
Herbivores
can only eat plants
(Feeding Relationships)
Carnivores
Can only eat animals.
(Feeding Relationships)
Omnivores
Can eat plants and animals
(Feeding Relationships)
Decomposers
Break organisms down and return nutrients to the soil. They are the recyclers in the ecosystem.
(Feeding Relationships)
Scavenger
Eat dead organisms that they did not kill themselves example: vultures
(Feeding Relationships)
Parasites
live off of another organism (host) and do not kill them usually (the parasite benefits, the host is harmed)
Food Chain
Is diagram of the linear feeding relationship of organisms in an ecosystem.
Rules in Drawing a Food Chain:
1. All food chains begin with a Producer (Autotroph or Plant)
2. All food chains end with a Decomposer
3. Arrows in a food chain show the direction of the energy flow
Grass -> Grasshopper -> Frog -> Snake -> Hawk -> Decomposer
Food Web
A diagram composed of many interlocking food chains. It is more accurate than a food chain because most organisms eat more than one type of food in their environment)
The Sun
The primary source of life’s energy on the earth.
Energy Pyramid
Is a diagram showing the energy available at each
trophic level. The bottom layer (Producers) has the greatest amount of
energy and the amount of energy Decreases by 90% at each level as you
move UP though the pyramid. Where does the energy go? Into the
environment (Lost as heat)
**Energy is not recycled in an ecosystem it is transferred from one trophic
level to the next.
Self Sustaining Ecosystem Requires:
- a constant source of energy ( usually the SUN )
- a process to capture the energy and store it in organic molecules. (Photosynthesis)
- a way to recycle elements back to the ecosystem. (Decomposers)
Ecological Succession
The orderly sequence of changes in the communities living in a given ecosystem.
Ecological Succession from bedrock to a forest:
Rock –> Lichens & Moss –> Grasses –> Shrubs –> small Trees –> Hardwood Trees
