Ecology: An Explanation

Define

• Ecology - study of the interactions that take

place among

• Biosphere - part of Earth that supports life,

including the top portion of Earth's crust,

the atmosphere, and all the water on Earth's

surface

• Biotic – living organisms

• Abiotic – non-living material

Define

• Biome - large geographic areas with similar climates and

ecosystems

• Includes:

– TUNDRA

– TAIGA

– DESERT

– TROPICAL RAINFOREST

– TEMPERATE RAINFOREST

– DECIDUOUS FOREST

– DESERT

– GRASSLAND

Define

• Organism – one of any living thing

• Population - all the organisms that belong

to the same species living in a community

• Community - all the populations of

different species that live in an ecosystem

Define

• Ecosystem - all the living organisms that live in

an area and the nonliving features of their

environment

• Habitat - place where an organism lives and that

provides the types of food, shelter, moisture, and

temperature needed for survival

• Niche - in an ecosystem, refers to the unique ways

an organism survives, obtains food and shelter,

and avoids danger

Define

• Limiting factor - anything that can restrict

the size of a population, including living

and nonliving features of an ecosystem,

such as predators or drought

• Carrying capacity - largest number of

individuals of a particular species that an

ecosystem can support over time

Define

• Pioneer species - a group of hardy organisms, such as lichens, found in the primary stage of succession and that begin an area's soil-building process

• Climax community - stable, end stage of ecological succession in which the plants and animals of a community use resources efficiently and balance is maintained by disturbances such as fire.

What is an ecosystem?

• An ecosystem refers to all the animals, plants, and nonliving things found in one place, and the way they all interact together.

• Different plants and animals live in different ecosystems.

• Different ecosystems can be close together.

• Some animals belong to several ecosystems.

What is an environment?

• Everything that affects an animal makes up its environment – where it lives, the weather and all the

living things it comes into contact with.

• Every living thing, including people, has an effect upon the environment.

Animal Adaptation

• All living things have to be suited to their environment pass on their genes.

• They must adapt (change) to the environment if they want to survive. – Carnivore - meat-eating animal with sharp

canine teeth specialized to rip and tear flesh

– Herbivore - plant-eating mammal with incisors specialized to cut vegetation and large, flat molars to grind it

– Omnivore - plant- and meat-eating animal with incisors specialized to cut vegetables, premolars to chew meat, and molars to grind food

Define

• Succession - natural, gradual changes in the

types of species that live in an area; can be

primary or secondary

• Primary succession – takes where no soil

exists

• Secondary succession – takes place where

soil is already present

How is the seal adapted to its environment?

Flippers to help it swim.

Streamlined shape.

Thick layer of body fat to keep it warm.

Strong teeth to catch fish.

Forward-facing eyes for clear vision ahead.

Hind legs have evolved into a a strong rudder-like tail.

Homes and Habitats

• The place where an animal lives is called its habitat.

• An animal lives where it can find food, water, shelter and a mate.

Living things

• All living things (organisms) need food (nourishment) to live.

• Living things in an ecosystem depend on each other for food.

•Herbivore – Animals that eat ONLY PLANTS are called

herbivores (or primary consumers).

•Carnivore – Animals that eat OTHER ANIMALS are called

carnivores.

•carnivores that eat herbivores are called secondary

consumers

•carnivores that eat other carnivores are called tertiary

consumers

•Omnivore - Animals and people who eat BOTH animals and

plants

Define

• Carnivore – eat omnivores or other

carnivores [other consumers]

• Herbivore – eat producers

• Omnivore – eat producers and consumers

Carnivores

Some animals, like the kingfisher, eat only other animals. These animals are

called “carnivores”.

Herbivores

Some animals do not eat other animals. They survive on plants and are known

as “herbivores”.

Omnivores

• Some animals, like us, eat both plants and animals.

• These animals are called “omnivores”.

Define

• Producer - organism, such as a green plant or alga, that uses an outside source of energy like the Sun to create energy-rich food molecules

• Consumer - organism that cannot create energy-rich molecules but obtains its food by eating other organisms

• Decomposer – consume wastes and dead organisms

Producers

• Plants are living organisms. They need nourishment to survive.

• Plants do not eat other plants or animals.

• Receive nutrients from dead matter

• Plants are called producers, because they make their own food inside themselves.

Consumers

• “Consume” means “eat”.

• Animals are consumers because they “eat” (consume) food provided by plants or other animals.

Define

• Predator – an animal that hunts and kills

other animals for food. A predator is a

consumer [carnivore or omnivore]

• Prey – an animal that is hunted and caught

for food. Prey is a consumer; it may be a

herbivore, omnivore, or carnivore.

Predator

A predator eats other animals.

Cats eat fish. So do bears!

Prey

Any animal which is hunted and killed by another animal for food is prey.

Predator

Prey

Match the predator to its prey.

Predators and Prey

Some animals are predators, some are prey - some are both.

The predator eats the prey, and the prey gets eaten by the predator.

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Why there are more

herbivores than

carnivores?

In a food chain, energy is passed from one link to another. When a

herbivore eats, only a fraction of the energy (that it gets from the

plant food) becomes new body mass; the rest of the energy is lost as

waste or used up by the herbivore to carry out its life processes

(e.g., movement, digestion, reproduction). Therefore, when the

herbivore is eaten by a carnivore, it passes only a small amount of

total energy (that it has received) to the carnivore. Of the energy

transferred from the herbivore to the carnivore, some energy will be

"wasted" or "used up" by the carnivore. The carnivore then has to

eat many herbivores to get enough energy to grow.

Because of the large amount of energy that is lost at each link, the

amount of energy that is transferred gets lesser and lesser .

http://www.vtaide.com/png/foodchains.htm

Define

• Food chain - chain of organisms along

which energy , in the form of food passes.

An organism feeds on the link before it and

is in turn prey for the link after it.

• Food web - Complex network of many

interconnected food chains and feeding

relationships; a group of interconnecting

food chains

Food Chains

A food chain shows what is eaten.

The fly is eaten by the thrush.

Food Chains

A food chain shows what is eaten.

The lettuce is eaten by the rabbit.

Food chains always start with a plant.

The lettuce is eaten by the slug, the slug is eaten by the bird.

Food Chains - a Reminder

• A food chain shows which animals eat other animals or plants.

• Plants don’t eat things.

• A food chain starts with what gets eaten and the arrows point towards what does the eating.

• Food chains only go in one direction.

Where do the arrows point?

The top of the food chain.

Some animals are said to be at the top of the food chain. This is because they are not hunted

by other animals.

No other animal hunts the lion. The lion is at the top of the food chain. Can you think

why?

Food Webs

• In the wild, animals may eat more than one thing, so they belong to more than one food chain.

• To get the food they need, small herbivores may eat lots of different plants, and carnivores may eat many different animals.

Food Webs

We can show this by using a food web, which is just a more complicated version of a food chain.

owl fox

rabbits

grass

mice

berries seeds

Breaking the Chain

• Organisms living in a habitat depend on each other.

• If one part of a food chain dies out or is greatly reduced, the consumers have to find alternative food, move away, or starve.

• This then affects more consumers in the same way.

Define

• Energy flow through an ecosystem - the

movement of energy through an ecosystem

through food webs. The transfer of energy

from one organism to another.

Define

• Energy pyramid – a way of showing

energy flow. As the amount of available

energy decreases, the pyramid gets smaller.

Each layer on a pyramid is called a trophic

level.

Energy Pyramid:

A diagram that

shows the amount

of energy that

moves from one

feeding level to

another in a food

web.

www.learner.org/.../life/session7/c

loser5.html

Describe each of the following terms:

Endangered or Extinct?

• The number of people in the world is growing at an alarming rate.

• But this is not true for all animals.

• In some cases, there are only a few of one type of animal left in the wild.

• These animals are endangered.

• If they die out completely, they become extinct.

Why does this happen?

There are lots of reasons why animals become endangered or extinct.

The most common are:

• loss of habitat (woodlands cut down, rivers drying up, hedgerows removed).

• chemicals or pollution poison the animals.

• hunting (for sport, their fur, tusks or meat).

Caring for the Environment

• It is in our own best interests to look after the world we live in.

• If a habitat is lost or damaged, it has an effect on everything else, even if we do not see or understand it straight away.

• Remember - once something becomes extinct, it’s gone forever!

Which diagram

best shows the

energy

transformation

from sunlight to

chemical energy

in an organism?

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• B – understand that plants are one of the organisms

(producers) that make their own food in this

process (photosynthesis).

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• Choice C is the correct answer because it identifies the

greatest limitation of this model.

• Since food webs are complex, not all organisms can be

included in one model.

• This diagram also illustrates how the flow of energy is

represented by arrows in a food web. The energy from the

organism that is consumed flows to the consumer.

• For example, the food energy from the deer flows to the

mountain lions because mountain lions eat deer.