Download ECOLOGY- (population growth) notes

ECOLOGY
Study Guide
Vocabulary
Living Things and the Environment
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Organism – A living thing
Habitat – An environment that provides the things a specific organism needs to live, grow, and reproduce
Biotic factor - The parts of a habitat that are living and interact with an organism
Abiotic factor - The nonliving parts of an organism’s habitat
Species – A group of organisms that can mate with each other and produce offspring that can also mate and reproduce
Population – All the members of one species living in a particular area
Community – All the different populations that live in an area
Ecosystem – The community of organisms that live in a particular area, along with their nonliving environment
Ecology – The study of how organisms interact with each other and their environment
Populations
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Birth rate - The number of births per 1,000 individuals for a given time period
Death rate - The number of deaths per 1,000 individuals for a given time period
Immigration – Moving into a population
Emigration – Leaving a population
Population density – The number of individuals in an area of a specific size
Limiting factor - Environmental factor that causes a population to stop growing or decrease in size
Carrying capacity - The largest population that an area can support
Interactions Among Living Things
1. Natural Selection – A process in which a characteristic that makes an individual better suited to an environment
becomes common in that species
2. Adaptation – The behaviors and physical characteristics that allow organisms to live successfully in their environment
3. Niche – An organism’s particular job or role
4. Competition - The struggle between organisms to survive as they attempt to use the same limited resources.
5. Predation – An interaction in which one organism kills and eats another organism
6. Predator – The organism that does the killing
7. Prey – The organism that is killed
8. Symbiosis – A close relationship between two species that benefits at least one of the species
9. Mutualism – A relationship in which both species benefit
10. Commensalism – A relationship in which one species benefits and the other is neither helped nor harmed
11. Parasitism – A relationship that involves one organism living on or inside another organism and harming it
12. Parasite – The organism that benefits during parasitism
13. Host - The organism that a parasite lives in or on (in parasitism)
Cycles of Matter
1. Producer – An organism that can make its own food.
2. Consumer – An organism that obtains energy by feeding on other organisms.
3. Decomposer – An organism that breaks down biotic wastes and dead organisms and return the raw materials to the
ecosystem.
4. Water cycle - The continuous process by which water moves form Earth’s surface to the atmosphere and back
5. Evaporation - The process by which molecules of liquid water absorb energy and change to gas
6. Condensation - The process by which a gas changes to a liquid
7. Precipitation - As water vapor condenses, the drops of water in the cloud grow larger. Eventually the heavy drops fall
to Earth as rain, snow, sleet or hail.
8. Nitrogen fixation - The process of changing free nitrogen into a usable form of nitrogen
9. Nitrogen cycle – The process in which nitrogen moves from the air into the soil, into living things, and back into the air
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Notes
Living Things and the Environment
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An organism gets food, water, shelter, and other things it needs to live, grow, and reproduce from its environment.
An organism interacts with the both the living (Biotic) and nonliving (Abiotic) parts of its habitat
Biotic factors of a habitat include plants, seeds, animals, and even bacteria.
Abiotic factors include sunlight, soil, temperature, oxygen, and water.
Ecosystems are organized from smallest to largest: organisms, population, and community.
The community and abiotic factors together form an ecosystem.
Because the populations in an ecosystem interact with one another, any change affects all the different populations that
live there.
8. Examples of ecosystems are prairies, deserts, oceans, ponds, and forests.
Populations
1. Some ecologists study populations and monitor the sizes of populations over time.
2. Populations change in size when new members join the population (through birth or immigration) or when members
leave the population (through death or emigration).
3. If birth rate > death rate, population size increases.
4. If death rate > birth rate, population size decreases.
5. Population density can be written as an equation: Population density = # of individuals / unit area
6. Limiting factors limit the growth of populations. Some limiting factors for populations are weather conditions, space,
food, and water.
7. The size of a population can vary, but usually stays near its carrying capacity because of the limiting factors in its
habitat.
Interactions Among Living Things
1. Natural selection works like this: Individuals whose unique characteristics are well-suited for an environment tend to
survive and produce more offspring. Offspring that inherit these characteristics also live to reproduce.
2. A niche includes what type of food the organism eats, how it obtains this food, and what other organisms eat it.
3. Every organism has a variety of adaptations that are suited to its specific living conditions and help it survive.
4. Three major interactions among organisms are competition, predation, and symbiosis.
5. In an ecosystem, there are limited amounts of food, water, and shelter. Organisms that share the same habitat often
have adaptations that enable them to reduce competition.
6. Predators have adaptations that help them catch and kill their prey. Some examples are a cheetah’s speed, and the
ability of owls and bats to hunt at night.
7. Prey have adaptations that attempt to help them avoid being killed and eaten. These can include warning coloring,
false coloring, protective covering, mimicry, and camouflage.
8. The three main types of symbiotic relationships are mutualism, commensalism, and parasitism.
9. Example of mutualism…In South America, stinging ants live only in acacia trees which have thorns that protect the ants
from predators. The ants attack other animals that approach the tree.
10. Example of commensalism…Bird builds a nest in a tree. The bird gets a place to live while the tree is unharmed.
11. Example of parasitism…Fleas and ticks on a cat or dog.
Cycles of Matter
1. Energy enters most ecosystems as sunlight which begins the process.
2. Energy moves through an ecosystem when one organism eats another.
3. Cycles of matter are important to our environment. These cycles include the water cycle, carbon cycle- oxygen cycle
and nitrogen cycle.
4. The processes of evaporation, condensation and precipitation make up the water cycle.
5. The processes by which carbon and oxygen are recycled are linked. Producers, consumers and decomposers play
roles in recycling carbon and oxygen.
6. Nitrogen cycles from the air to the soil, into living things and back into the air or soil.
7. Each organism in an ecosystem fills the energy role of producer, consumer or decomposer.
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