Biology 1

Introduction to Ecology

Ecology: the study of the relationships living things have with

each other and their non-living environment.

Biotic Factors: all the living things in an environment

What biotic factors can you identify?

Abiotic Factors:

All the non-living factors in an environment.

The soil (dirt) in an environment cannot be called simply abiotic or biotic. Discuss.

Species: a group of organisms that can interbreed and produce fertile offspring in

nature.

A few shark species What does it mean that these sharks are

different species?

VocabularyHabitat (address)

The place an organism lives.

Think of a zoo. There is usually an attempt to mimic the organism’s “habitat.”

Niche (occupation) The role that an organism plays in its environment.

How does the organism obtain food? What are some of its relationships with other organisms?

Can you describe the habitat and niche of some organisms?

Vocabulary: Levels of Ecology

Organism (any single living thing) Population (members of same species living in one place)

Community (different populations interacting in an area) Ecosystem (a complete community + its abiotic environment) Biosphere (all parts of Earth where life exists, both biotic and abiotic)

Population: a group of the same species living in the same area at

the same time.

Community: interacting groups of populations

Ecosystem: a community and its abiotic environment.

A Freshwater Pond

lighthumidity

Mineral content

Water temperature

Biomes (not required): Large, ecologically similar areas.

Biosphere: all the interdependent and interrelated ecosystems of the earth

Population Ecology: the interactions of one population, especially relating to

population size

What increases population size?• Natality (births)• Immigration (moving into a

population)

What decreases population size?• Mortality (deaths)• Emigration (moving out of a

population)What are some factors that would influence natality and mortality rates? Immigration and emigration?

Natural Resources:• Things organisms need to survive

Limiting Factors (environmental resistance):• When resources are in short supply

and impact population growth.

Carrying capacity: the maximum population than an environment can

sustainably support

A population may plateau OR temporarily overshoot the carrying capacity. If overshot, survival depends of severity of overshoot and speed of environmental recovery.

Compare and

contrast these

graphs.

Apply population ecology ideas to the global human population.

COMMUNITY INTERACTIONS: Relationships between species

Relationship Effect

3 types of Symbiosis:A continuing and close relationship between species

Mutualism + / +

Commensalism + / 0

Parasitism + / -

Pathogen / Host + / -

Not considered symbiosis

Predator / Prey + / -

Herbivore / Plant

+ / -

Competition - / -

MUTUALISM: a + / + interaction

Lichens: an alga and a fungus!

What benefit does each species receive?

MUTUALISM: a + / + interaction

Cleaner Wrasse and Parrot Fish

Ants and Acacia Trees

What benefit does each species receive?

MUTUALISM: a + / + interaction

Ants and Aphids

PARASITISM: a + / - interaction

PARASITISM: The Cuckoo

PATHOGEN / HOST: a + / - interaction

COMMENSALISM: a + / 0 interaction

Scavengers benefit from dead

organisms that are not affected.

Cattle Egrets eat the insects that

these cattle scare up.

COMMENSALISM: a + / 0 interactionShark and Remora

PREDATION: a + / - interaction

HERBIVORY: a + / - interaction

COMPETITION: a - / - interaction

Male weaver birds: compete to attract a

mate. This is INTRASPECIFIC competition:

competition within the same species

COMPETITION: a - / - interaction

Invasive starlings will out-compete native bluebirds for

nesting holes. This is INTERSPECIFIC competition:

competition between different species

Energy and Ecology:ALL living things need both matter and energy.

Matter and energy are transferred:• between organisms• between organisms and the abiotic

environment

What is different between the transfer of ENERGY and the transfer of MATTER?

MATTER: the same atoms are use over and over again. Matter is recycled, not “lost”.

ENERGY: flows one-way through the biosphere and leaves the Earth. A new input of energy is continually needed.

All organisms need energy to live.

Energy and Ecology

Where do you get your energy?

How did the things you eat get their energy?

Trace the energy back to its source. What is the source of energy for (almost) all living things?

Ecology Vocabulary

Tip: Learn word parts to help you understand new terms:

Prefixes:“Auto” = by itself“Hetero” = from others

Base-word:“Troph” = energy (obtaining food)

Sometimes you see the suffix:“ic” = pertaining to

Can you think of examples of words that have these parts?

Trophic Levels: how organims obtain energy (their food)

All organisms need energy to live.AUTOTROPHS (producers): Most

use energy directly from the sun

produce their own food by photosynthesis in chloroplasts

often plants (also some bacteria, lichens, etc)

Also break down food when and where needed to release energy (respiration)

All organisms need energy to live.HETEROTROPHS get energy from

consuming other organisms

often animals that release energy by respiration in their

mitochondria

Two major types of Heterotrophs:

Consumer - a living thing that eats other living things to survive. It cannot make its own food.

Examples…humans, fish, spiders

Decomposer - an organism that breaks down and digest the remains of organisms.

Examples…. fungi and some bacteria

Decomposers are essentialbecause they are the

nutrient recyclers!Kinds of Decomposers:1.) detritovore: (have a mouth) feed on dead organisms or their wastes

eg. worms, millipedes, dung beetles2.) Saprotroph: (without a mouth) secrete digestive enzymes into their environment and absorb the nutrients.

eg. Bacteria, fungi

What is the difference between Detritivores and

Saprotrophs?

• Detritivores usually have mouths, Saprotrophs do not.

• Detritivores are mostly animals while saprotrophs are mostly bacteria and fungi.

• Detritivores consume lumps of dead organic matter separately, while saprotrophs absorb chemically digested food.

• Saprotrophs digest their food externally, whereas detritivores do it internally in their digestive system.

Remember to follow the energy!

Find several major errors / omissions in this diagram (from a respected publisher!)

Food chain: One possible energy pathway through an ecosystem.

Shows who eats whom.

Let’s play “follow the energy!” The arrows show you where it goes!

Food web: All possible energy pathways through an ecosystem.Shows alternative food choices.

Trophic Levels and Levels of Consumers

First TrophicLevel

Second Trophic Level

Third Trophic Level

Fourth Trophic Level

Note that the trophic level is always one more than the consumer level. Why?

Food Web: Problems with Trophic Levels

What is the trophic level of the fox?

1

2

3

1 1

2

3

4

2

3

4

5

We know that energy is transferred. How much?

About 10% between trophic levels.

Trophic Level: Position in a food chain

Energy Efficiency in Food Consumption

Why is it said that eating vegetarian food can reduce food shortages and

starvation?

Why can only 10% of energy be transferred to the next trophic level?• Not all organisms

are eaten• Not all parts of

organisms can be digested

• Converting energy for the functions of life is not 100% efficient (some is always) lost as heat

Energy is not created or destroyed. If only 10% of energy is transferred to the next trophic level, where is the rest?

Cycles in Nature:ALL living things need both matter and energy.

Matter and energy are transferred:• between organisms• between organisms and the abiotic

environment

What is different between the transfer of ENERGY and the transfer of MATTER?

MATTER: the same atoms are use over and over again. Matter is recycled, not “lost”.

ENERGY: flows one-way through the biosphere and leaves the Earth. A new input of energy is continually needed.

Cycles of Matter:Water, Carbon, Nitrogen, etc.

CARBON CYCLE

Follow the carbon atoms.

Where do they go?

combustion

Bio =

Biodiversity

What does “Bio” mean?

Biodiversity

Diversity = Variety

What does “Diversity” mean?

There are 3 components of biodiversity

1. Diversity within genesChihuahuas, beagles, and Rottweilers are all dogs—but they're not the same because their alleles are different.

Chihuahua BeagleRottweilers

2. Diversity of speciesFor example, there about 260 species of monkeys, 5,000 species of dragonflies, and 350,000 species of flowering plants.

Saki Monkey Golden Skimmer Meadow Beauty

3 components of biodiversity

3. Variety of ecosystemsPrairies, Ponds, and tropical rain forests are all ecosystems. Each one is different and supports a unique set of species.

Paines Prairie

Hoh Rain Forest

Florida Sand hill Pond

3 components of biodiversity

Which has more biodiversity?

A B

Threats to biodiversity

1. Habitat destruction or loss including1. Land cleared for agriculture, construction,

resource extraction, etc.

2. Climate change impacts

3. Pollution

2. Invasive Species

3. Direct hunting or exploitationFor a video about biodiversity watch

“Extinction!” video from the evolution unit.

Why do we want biodiversity?1. Intrinsic Value = Something that has value in and of itself. Do we value all life?

2. Utilitarian Value = Something that has value as a means to an end. What do we get from biodiviersity?

• Food, shelter, medicine, and other products

• Stable ecosystems and epidemic-resistant species

• Ideas for research and sources of new information

The Earth is losing species at an alarming rate

• Some scientists estimate that dozens of species are going extinct each day, many of which humans never studied

Madagascan RosyPeriwinkle

This periwinkle was used in traditional medicine and became endangered due to habitat destruction. Scientists found that it has anti-cancer properties. It now gives us cisplatin, one of our best treatments for leukemia.

We came close to losing this species. What else might we be losing every day without knowing it?

Solutions, not just problems

• Eco-Tipping Points– Small actions that lead to large

positive changes– For more information

• A Thailand case study– Reversing Tropical Deforestation– Video presentation