Science

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Ecology Textbook

Sections 2.1 and 2.2

SpeciesPopulationsLimiting factorsCommunitiesHabitatsNichesCooperationCompetitionSymbiosis

Species• Scientists group living

things according to their shared characteristics

• The smallest grouping is a species

• Scientists consider organisms to be members of the same species if the organisms are so similar that they can successfully reproduce

Cinnamon Cinnamon Green CheeksGreen Cheeks

Yellow-sided Yellow-sided Green CheekGreen Cheek

Population• A group of

species that live in a particular bounded area is a population.

• In ecology, members of the same species that live in a different area belong to a different population

What is a large group of species

in a bounded area?

A

Population

Factors Affecting Populations

For any population to thrive, there must be enough food, water, light and living space. These factors are known as limiting factors.

Limiting factors determine how many organisms can live in an environment.

An environment contains only limited amounts of water, food, or living space. When any of these factors becomes scarce it can affect population size.

Name the four limiting factors that affect populations

Food

Water

Light

Living space

How Limiting Factors Affect A Population

Plants make their own food. All other organisms obtain food and energy by eating other organisms.

Food is a limiting factor because only so much is available in an ecosystem.

Food

The cells and tissues of plants and animals are made primarily out of water.

All living organisms need water to move materials throughout their body’s tissues and cells.

Water

Plants and other organisms that make their own food need sunlight to carry out photosynthesis.

If light is limited, the growth of these organisms will also be limited.

Light

Organisms need space to live, reproduce and obtain resources.

Living space

The place where an organism lives is called it’s

habitat.

Carrying Capacity

The largest population that an environment can support over a long period of time is known as the environment’s carrying capacity.

What is the largest population that an environment can

support over a long period of time

Carrying

Capacity

When a population grows larger than its carrying capacity, limiting factors cause the population to get smaller.

Example- Example- Drought

= decreased plant production = decreased food

supply = increased starvation

Habitat

• The natural environment in which a living thing gets all the it needs to live is called it’s habitat.

• Habitat is the physical location where plants and animals live

• A habitat is filled with many different species.

Future Natural Habitat for ManFuture Natural Habitat for Man

What is the physical location where plants and

animals live known as?

A

Habitat

Niche• The role that each organism

plays in a habitat is referred to as its niche.

• The niche an organism fills in a habitat is not limited to its place in the Food Web.

• Generally no two species have the same niche

Niche Examples

• Trees may be seen as a producer of leaves that the caterpillar consumes.

• Trees may also provide a nest for birds or other animals or insects

Community

A group of populations that live in a particular area and interact with one another are called a community.

Populations of frogs, fish, cattails, and snakes live in a pond community

What is the difference between a

community and a population?

A population is a large group of species that live in a particular area

A community is a variety of populations that live and interact together in a particular area

The Environment can be organized into five levels

1. Organism- a single living thing

2. Population- a group of organisms of the same species that live in the same area

3. Community- made up of the living components of the ecosystem

4. Ecosystem- living and non-living factors interact to form a stable system

5. Biome- similar climate, plants, and animals throughout an area

Name the five levels of an environment

1. Organism

2. Population

3. Community

4. Ecosystem

5. Biome

Cooperation• Sometimes organisms work

together in a way that benefits the whole group

• Killer whales hunt in packs known as Pods

• Lions live in family groups called prides in which members hunt in teams and share the kill with everyone

Interactions and Relationships Among Organisms

Competition

Predation

Symbiosis

The relationships and interactions that species form in an ecosystem can be divided into these three categories.

CompetitionCompetition occurs when two or more individuals or populations try to use the same limited resource such as food, water, shelter, space or sunlight.

Competition may occur within species or between species. Only those organisms able to get the resources they need will survive.

Examples:

Two herbivores competing for the same plants.

Different species of trees competing with each other for sunlight and space

PredationPredation is a type of feeding relationship in which one animal

captures and eats another animal for food.

The animal that is eaten is the prey.

The animal eating the prey is the predator.

Predator-prey relationships help to keep an ecosystem in balance by preventing any one population from getting too large.

Symbiosis

A close, long-term association between two or more species is called Symbiosis.

The individuals in a symbiotic relationship can benefit from, be affected by, or be harmed by the relationship.

Often one species in a symbiotic relationship lives in, on, or near the other species.

Symbiotic relationships that occur in nature are classified into of these three

groups:

Mutualism

Commensalism

Parasitism

MutualismMutualism is a relationship in which both species benefit.

Example

Pollination

A relationship between flowers and insects

A flower provides a food reward to an insect in the form of nectar (a sugar rich solution). If the food reward is large enough, the insect is likely to go looking for flowers of the same plant species after it is done visiting the first flower. The flower species then gets its pollen passed on to another plant so that it can reproduce.

Commensalism

Commensalism is a type of symbiosis in which one species benefits while the other seems to be unaffected.

Example

The clown fish and the sea anemone

The clown fish lives among the deadly tentacles of a sea anemone. The anemone's tentacles contains nematocyst, which paralyzes the anemone's prey and protect it against predators. Yet the clown fish is not stunned. Living within the anemone's tentacles, the clown fish gains protection, as well as food from leftovers of the anemone's meals.

ParasitismParasitism is a symbiotic association in which one organism benefits while the other organism is harmed.

The organism that benefits is called a parasite. The organism that is harmed is called the host.

The parasite gets nourishment from the host. The host in turn is weakened and may die.

Some parasites live outside the hosts body. Example: ticks or fleas

Other types of parasites live inside the host’s body: Example: tapeworms

Name and describe three symbiotic relationships in

nature.

The

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