organisms and the environment

How is energy released?

Energy is released during processes, such as respiration and ultimately become heat energy, which is transferred to the surroundings

Define a producer, a consumer, a food chain and a decomposer

A food chain shows a transfer of energy from one organ organism to the next beginning with a producer example

grass → grasshopper → lizard → snake → eagle

a producer is an organism that makes it’s all organic nutrients usually using energy from sunlight through Photosynthesis

a producer is an organism that makes it’s all organic nutrients usually using energy from sunlight through photosynthesis for example, green plants are consumers

A decomposer is an organism that gets its energy from dead or waste organic material for example bacteria fungi

What is interdependence?

Interdependence means organisms depend on each other to remain live, grow and reproduce for example bees depend on flowers for food and flowers depend on bees for pollination

Define overharvesting give 3 examples and its 5 effects

Overharvesting is taking too many organisms from a population, causing their numbers to decrease for example

• over fishing

• excessive hunting

• harvesting animals for body parts

effects:

• It’s population decreases

• predators that feed on it may have less food

• It’s prey may increase of because of fewer predators

• it disrupts the entire food web

• the species may eventually become endangered or extinct.

what does introducing a foreign species mean (1)

what that introduced species may do (6) and it’s effect (1)

Introducing a foreign species means introducing a species into a habitat where it does not naturally occur.

The introduce species may :

• compete with native species for food

• eat native species

• have few natural predators

• reproduce rapidly

• reduce populations of native species

• disrupt existing food webs.

This can reduce biodiversity and cause native species to become endangered

draw a pyramid of numbers

Draw a pyramid of biomass

Why is the pyramid of biomass better than a pyramid of numbers?

A pyramid of numbers can be misleading because organisms can be very different sizes , e.g one tree can support One thousand insects but but a pyramid of biomass takes the mass of organisms into account. It gives a better representation of the amount of living organisms at each trophic level.

Draw a pyramid of energy

Explain the transfer of energy in a pyramid of energy and 4 reasons why energy is lost

Amount of energy decreases at each higher traffic level. energy is lost as it passes between traffic levels because energy transfer between traffic levels is not 100% efficient.

energy is lost because :

• organisms use energy for respiration

• energy is released to the environment as heat

• energy is used for movement

• energy is used for growth and reproduction

In a pyramid of energy, why may they not be another trophic level?Z

Energy is lost at each traffic level solar energy is available to the next level. Eventually, there is insufficient energy to support another traffic level.

Why is it more efficient for humans to eat crops directly rather than feeding crops to livestock than eating the livestock

When crops are fed to livestock much of the energy in the crops is lost by the livestock because it uses energy for

• respiration

• producing heat

• maintaining body functions

• movement

• growth

and only some of the energy from the crops become part of the livestock biomass

What is the population? What is a community and what is an ecosystem?

A population is a group of organisms of one species living in the same area at the same time

a community is all the populations of different species in an ecosystem for example, in a lake, the community could include :

• fish

• insects

• amphibians

• plants

• algae

• 
  

an ecosystem is a unit containing the community of organisms and the environment interacting together .

ecosystem = community + nonliving environment. The environment includes facts such as

• water,

• soil,

• temperature,

• light,

• and mineral ions

What are the four factors affecting population growth?

Food supply, competition, prediction disease

How does food supply affect population growth?

If there’s plenty of food organisms have enough energy and nutrients to grow and reproduce, this can increase population size if food becomes scars competition increases and organisms may die or reproduce less

How does competition affect population

Competition occurs when organisms compete for limited resources such as food, space and mates more competition. Can we reduce population groups?

How does prediction affect population Size

predators kill and eat prey so when there are more predators that you were prey, and when the fewer predators the prey population increasesz

How does this disease affect population size?

Disease can spread easier when there are many organisms in a population disease can :

• increase death rate

• reduce population size

• reduce population growth

What happens at phase a,b,c,d

A → lag face

• the small population population increases slowly

• they are few organisms reproducing so the population increase is small

  
  

B → exponential (lag )phase

• population increases rapidly.

• There are plenty of resources such as food and space

• there’s a little competition

• population can increase because organisms are reproducing successfully.

C → the stationary Phase

• population size becomes constant

• resources like food and space become limited

• competition increases

• birth rate equals death rate

• population reaches its max level for that environment

• 
  

D → death Phase

• death rate surpasses birth rate

• population size decreases this can happen because there isn’t enough food wns space

• waste may accumulate and disease may spread.

What is a limiting factor and give 4 examples

Limiting factors affect that prevents population from increasing beyond the certain size. The factors include

• food supply

• disease

• competition

• predation

As population becomes larger, there’s more competition for food and space. This reduces the rate of population growth and helps cause the dictionary Phase.