Last Science Test of 7th Grade

Study hard, finish strong. (is not fully done does not include lessons 6 and 7 and is not based off of the study guide as that has not been given out yet.

System

A group of interacting, interrelated, or interdependent parts forming a complex whole

Ecosystem

A system made of  living and nonliving parts that  interact to support life.

Abiotic

The non-living parts of the environment.

-Sun

-Soil type

-Weather

-Air

Biotic

The living parts of the environment.

-Animals

-Plants

Habitat

A habitat is a place where a population of organisms live.

-Desert

-Forest

-Grassland

-School yard

-Ozarks

Organism

Any living thing, plant or animal.

Niche

How an organism fits into an ecosystem.   Its role or job in an ecosystem. 

-No two organisms can fill the same niche at the same time (for very long)

Autotroph

Produces their own food. For example, a plant uses photosynthesis to convert sunlight into food and energy

Heterotroph

Consumes food produced by other living things

Symbioses

When two organisms live in close contact

Commensalism

 One species gets food or shelter from the other without harming the other species

Mutualism

 Two species live together and they both benefit

Parasitism

One species nourishes itself while the other is harmed.

Population

The number of species in a specific area

Community

Several populations interacting in the same area 

Ecosystem

A biological community of interacting organisms and their physical environment

Biome

A large group of ecosystems spread out over a major geographical area. Flora and fauna (plants and animals) adapted to a specific climates.

Biosphere

The part of the earth’s crust, water, and atmosphere that supports life.

Biodiversity

The variety of life in an ecosystem.  The greater the diversity, the healthier/more stable the system.   

Population Size

Total amount of organisms of a single species in an area.

Demographics

Characteristics of a population, such as age, habits and  traits/group traits.  

Population density

How the population is spread out in an area  

Population Spacing (in general)

Populations can be spaced differently. The differences help animals in different ways.

Clumped

Gathered around resources

Uniform

Evenly spaced, lots of resources. Usually animals that are territorial have this

Random

No pattern, populations move frequently.  Plants  follow this pattern when seeds can be randomly dispersed by the wind. 

Geographic Range

Physical limits of the population.  Such as temperature, rainfall or competition

Population Growth

A growth curve shows how fast a population of organisms will grow. 

Carrying Capacity

The maximum population size the environment can sustain.  

Limiting Factors

Specific conditions that limit the growth of a population.

Biological limiting factors

redation, parasitism, mutualism, disease

Non Biological limiting factors

Temperature, precipitation, pollutions, amount of sunlight, water. 

Energy in Ecosystems

All energy on the Earth comes from the sun.

Models

Tools used to represent complex topics and make them easier to understand. 

Food Chain

Food chains demonstrate the transfer of matter and energy from one organism to the next. 

Trophic Level

Each level in the food chain. Trophic means energy.

Primary Producers

Pull nutrients from the soil and manufacture their own food via photosynthesis.  

Primary consumers

Herbivores that eat plants (primary producers)

Secondary consumers

Carnivores that eat herbivores

Tertiary Consumers

Carnivores that eat other carnivores

Apex predator

Predators in the top of the in food chain. 

Food webs

A system of interlocking and interdependent food chains.

Energy Pyramids

Models that represents energy transfer in an entire ecosystem.  They help us understand why certain populations of organisms are very large and other populations are very small.

Cycle

A cycle is a model that is used to show how elements, compounds or energy are used in an ecosystem. 

Abiotic and biotic factors

All ecosystems are a unique mix of biotic(living) and abiotic(nonliving) components.  

Conversation of matter

Matter is never created or destroyed; it is converted from one form to another.

Water cycle

The sun is the driving force of the water cycle.  

Radiation from the sun heats our planet and drives this cycle. 

Water cycle terms

Evaporation: Water evaporating into the atmosphere

Condensation: Water condenses into droplets

Precipitation: Water falls to the Earth as rain, sleet, snow or hail. 

Transpiration: Water being transferred from living things, like leaves giving off moisture

Carbon cycle

A model that explains how carbon is converted back and forth throughout our ecosystems.

All living things are made of carbon.

Plants and carbon cycle

Plants use photosynthesis to collect carbon from the atmosphere and convert it into sugar. 

Nitrogen

Nitrogen is the most abundant element in the atmosphere.  (78%)

Nitrogen is an important building block of all biological life ( proteins and DNA)

Nitrogen cycle

Nitrogen is pulled from the atmosphere by plants that can grab it from the air.  

This is called nitrogen fixation

In the ground, bacteria and decomposers can convert the nitrogen to forms that can be used by plants.

Succession

The process of change of species in an ecological community over time.  

Succession is a slow, gradual process of change.

Primary succession

Growth of organisms in an ecosystem that hasn’t had life before. 

Involves pioneer species:  Tough species that can colonize environments with very little nutrients. 

Benefits of pioneer species

These photosynthetic organisms will decay and cause weathering.

This will allow soil to form which leads to the growth of larger vascular plants.  

Secondary succession

Change and growth at a site that was severely disturbed or wiped out by a disaster of some sort. 

Example a wildfire volcanic eruption, or lightning strike. 

Existing soil is fertile from previous plants and seeds.  This leads to much faster growth compared to primary succession.

Climax Community

A community of plants and organisms that are stable and has grown to maximum size. 

Climax communities are reffered to as_____________?

 old growth forest.

Why is succession important?

Succession provides diversity to biotic communities.