BIOLOGICAL COMMUNITIES

Chapter 17Ecology Unit

What happens in communities? We all know that ecology is the study of

interactions among species and/or between species and their respected environments.

We are now going to learn about some of those interactions.

Co-evolution Because organisms are constantly

interacting, wouldn’t it make sense that they would adapt to each other as well?

co-evolution is the back-and-forth evolutionary adjustments (adaptations) between interacting members of a community

Example: plants and their pollinators

Co-evolution happens through many interactions There are interactions in which both of

the species benefit This is called mutualism, and is a +/+

interaction Examples of mutualism are plants and

pollinators, or ants and acacia trees

Co-evolution happens through many interactions Predators and prey co-

evolve as well In predation, one

organism is killing another for food

Predation is a +/- interaction, in which one organism benefits while the other suffers

Prey evolve to better avoid predators and predators evolve to better catch prey

Co-evolution happens through many interactions In their own rights, parasites can

be considered predators because they use other organisms as a food source

However, parasites generally don’t kill their hosts

Parasitism is also a +/- relationship because the parasite benefits while the organism it’s residing in (the “host”) suffers

Hosts evolve to be less susceptible to parasites, while the parasites evolve to either work around the host’s susceptibility or to be able to survive in a variety of hosts

Co-evolution happens through many interactions There are symbioses in

which only one of the two species are affected

In this symbiosis, called commensalism, one of the species is benefitted while the other isn’t affected positively or negatively +/0

Example of this is clown fish in anemones

Co-evolution happens through many interactions Herbivores may not be seen

as predators, but to plants they most certainly are

Plants have different methods for defense against herbivores, both physical and chemical

On the other hand, as plants gain these defenses (such as secondary compounds which chemically ward off herbivores), the herbivores are gaining resistance to these defenses

Some species are necessary in an ecosystem There are some species that

are so important that their population being present is vital for the survival of an ecosystem

These are called keystone species

Changes in the populations of these species can cause huge changes in the structure of a community

Ex: starfish! They keep the population of mussels under control so they don’t take over the ecosystem.

Climate impacts communities How do you think climate impacts

communities?

Climate impacts communities Different organisms fare better in different

climates Climate is the average year-to-year

conditions of temperature and precipitation in an area over a long period of time

Examples of organisms that are seasonal? That live in different places at different points of the year to remain in a similar climate?

Biomes are classified partially by climate So, where do scientists use the

information about biotic and abiotic factors of an ecosystem?

One way this information is used is to classify the different biomes

Biomes are described in terms of abiotic factors such as climate and soil type, as well as the biotic factors of what plants and animals live there.

There are lots of biomes Tropical rain forests

- abiotic: hot and wet year-round with thin, nutrient-poor soil subject to erosionbiotic- many levels of vegetation fighting for sunlight; many species of animals (many with strong abilities of camoflauge)

Located in Central and South America, Africa, and Asia

There are lots of biomes Tropical dry forests

-abiotic: warm year round; alternating wet and dry seasons; rich soil-biotic: leaf shedding trees, plants with thick cuticles to reduce water loss; animals that have long periods of inactivity during the dry season

Found in parts of Mexico, India, South America, and Southeast Asia

Other Examples of Biomes The rest of the biomes include

savannas, deserts, temperate grasslands, temperate woodlands, temperate forests, coniferous forests, boreal forests, and tundra

Each experiences different climates, and therefore hold different types of life (some seasonal, some year round)

Florida’s biome?

Florida’s biome(s) Florida is a majority

temperate forest with some tropical grassland/savanna

Which part of Florida would comprise the tropical grassland?

Florida’s biome(s) Temperate Forest

-abiotic: cold to moderate winters; warm summers; year-round precipitation;fertile soils-biotic: trees that drop their leaves to go dormant in winter; animals that can cope with changing weather, hibernate, or migrate

Savanna/Tropical Grassland-abiotic: warm; seasonal rainfall; compact soils; frequent fires set by lightning-biotic: plants with waxy cuticles to prevent water loss; animals who move when water is low

Organisms have native habitats Every living organism has a

habitat/location that they are native to When these organisms enter an

ecosystem that they are not native to, they are considered non-native to that environment

These organisms can enter the ecosystem in multiple ways, such as?

Organisms have native habitats Non-native species enter the

ecosystems in more than one way Some enter the ecosystem by accident

(such as through importing/exporting goods)

Some are deliberately introduced by humans for reasons such as controlling other populations

Organisms have native habitats Some of these species that are

introduced to new ecosystems do not hurt it

However, some are extremely disruptive to the ecosystem

Those species that are considered disruptive to the ecosystem that they have been introduced to are considered invasive species

Invasive species hurt ecosystems Invasive species can do

many things to hurt the ecosystem1. take food from the native species2. mate with the native species, making hybrid species3. take habitat from native species

Some species that we may have seen around us all of our lives may actually be invasive

Ex: Iguanas in Florida

Ecosystems aren’t just on land Ecosystems are

present in the water as well

Ponds, lakes, rivers, oceans, etc. all contain ecosystems

Ecosystems aren’t just on land Bodies of water have different levels, each with

defining characteristics The photic zone of a body of water is the sunlit

region near the surface-what process can occur?-phytoplankton (algae) and zooplankton (animals that eat phytoplankton) live at this level

The aphotic zone is dark; underneath photic zone-photosynthesis cannot occur-much aquatic life lives in this zone

Ecosystems aren’t just on land Oceans are a great place to find a

diversity of life at many levels Very deep in the ocean, where we have

only recently been able to travel, there have been many interesting (often weird) fish and invertebrates discovered

These animals are accustomed to the deep, cold, high pressure conditions of the deep ocean

Ecosystems aren’t just on land In freshwater bodies (lakes and ponds), there are

also zones of where animals live-the littoral zone is the shallow zone near the shore that holds aquatic plants, predatory insects, amphibians, and small fish-the limnetic zone is farther away from the shore, close to the surface and holds algae, zooplankton, and fish-the profundal zone (not all lakes/ponds have these) is deep water where bacteria and wormlike organisms decay debris and recycle nutrients

Examples of the bizzare

Self Check Think about the environment. What do

you know about the environment? What have you learned and/or heard about the environment in recent years? Who do you think should be responsible for taking care of the environment? Are the government and environmental agencies doing enough? Write your answer in a paragraph.