Species Interactions

describe the different types of species interactions as well as coping mechanisms to competition, predation and coevolution

what are the species interactions

• competition

• predation

• parasitism

• mutualism

• commensalism

• amensalism

“in looking at nature, never forget that every single organic being around us may be said to be striving to increase its number” by?

Charles Darwin, 1859

an interaction between organisms or species in which both require a resource that is in limited supply (such as food, water, or territory)

competition (-/-)

• intraspecific competition and interspecific competition

this happens when members of the same species compete with each other for resources like food, water, shelter, or mates

Intraspecific competition

• for example, if you have a garden with many tomato plants, they might compete for sunlight, water and nutrients

this occurs when members of different species compete for the same resources

Interspecific competition

• for instance, in a forest, rabbits and deer might compete for the same type of plants to eat

• consumption of resources by two species, but one species may limit resource availability to other species

• one species more efficiently uses a resource

exploitative competition

examples of exploitative species

• ants and rodents compete for seeds'

• occur among plants in the forest

happens when organisms directly fight or block each other from accessing resources, rather than just using up those resources

Interference competition

• this can involve aggressive behaviors, physical obstruction, or even producing chemicals to harm competitors

  • animals might physically fight over territory or food

  • plants may release chemicals into the soil to prevent other plants from growing nearby

between individuals of different species, fighting over the same resource

aggression

one species has an advantage over the other

asymmetric

• a biological process where plants affect, often inhibitory, the growth and germination of other species within their space

• production of compounds that inhibit the growth of other plants

• chemical release by one plant species negatively impacts another

allelopathy

• important desert shrub

in coastal sage scrub (California)

• releases catechin into soil

• when absorbed by roots of other plant species, causes wave of cell death to move up roots into stems

• aids invasiveness

• invasive shrub

Paper mulberry (Broussonetia papyrifera)

• releases phytotoxins that gets concentrated in the soil’s upper surface which inhibit the growth of seedlings in many plants such as conifers by killing their germinating seeds

Bracken fern (Pteridium aquilinum)

methods of obtaining evidence of competition:?

• Tansley’s Experiment

• Connell’s Experiment

• Diatom experiment

conducted in 1917, aimed to understand how competition affects the distribution of two plant species, Galium saxatile and Galium sylvestre, in different soil types

Tansley’s Experiment

grows best in calcareous soils as observed in nature

G. sylvestre

grows best in acid, peaty soils, as observed in nature

G. saxatile

what happens when you plant together G. sylvestre and G. saxatile

The results showed that when grown together, G. sylvestre outcompeted G. saxatile in calcareous soil, while G. saxatile dominated in acidic soil. This experiment demonstrated the concept of competitive exclusion, where one species outperforms the other based on environmental condition, influencing their natural habitats

studied competition between two barnacle species, Balanus and Chthamalus in the intertidal zone

Connell’s Experiment

• can survive in the upper intertidal zone (high tide area) because it’s more resistant to drying out

Chthamalus

• out competes Chthamalus in the lower intertidal zone (low tide area) where conditions are better

Balanus

refers to the role or space a species occupies in its environment, including where it lives and how it uses resources

Niche

what can you observe in Connell’s experiment

Connel observed that Chthamalus could survive across the entire intertidal zone (its fundamental niche) but was restricted to the upper zone (its realized niche( because Balanus outcompeted it in the lower zone.

This competition occurs because Balanus grows faster and physically pushes Chthamalus off rocks in the lower zone

• the experiment demonstrates how interspecific competition can limit a species realized niche, forcing it to occupy only part of the space it could theoretically inhabit without competitors

shows how two species, Asterinella formosa (Af) and Synedra ulna (Su), compete for silica, which they need to build their cell walls.

Diatom experiment

what happens when Asterinella formosa (Af) and Synedra ulna (Su) are grown separately?

when grown separately, both thrive. However, when grown together, Synedra ulna is better at absorbing silica. As a result, it reduced the silica levels so much that Asterinella formosa can’t survive, leading to its extinction in the shared environment

effects of competition

• Competitive exclusion principle (Gause’s Law)

• Character Displacement

what leads to competitive exclusion?

• strong competition can lead to competitive exclusion, local elimination of a competing species

what is the competitive exclusion principle

• states that two species competing for the same resources cannot coexist if their niches overlap significantly.

explain the graph

• the principle states that two species competing for the same resources cannot coexist if their niches overlap significantly

• in the graph, species A and B have overlapping zones where they compete for food

• in the overlap zone, one species will outcompete the other over time

• the weaker competitor must adapt, move to a different niche or face extinction

• this principle explain how competition shapes ecosystems and species survival

• evolution of anatomical differences that reduce competition between similar species

character displacement

occurs when a species separates into two separate groups that are isolated from one another

Allopatric speciation

• occurs when population are physically separated by a geographic barrier (e.g mountains, rivers, oceans)

• the separation prevent gene flow, leading to independent evolution and eventual reproductive isolation

• ex: Darwin’s finches evolving on different islands due to ocean barriers

occurs when there are no physical barriers preventing any members of a species from mating with another, and all members are in close proximity to one another

Sympatric speciation

• happens within the same geographic area, without physical barriers

• populations become reproductively isolated due to factors like mutations, polyploidy, or ecological niche differences (eg, preferring different food sources)

• ex: fish in the same lake evolving into distinct species by adapting to different feeding zones

is a driving force for species to evolve adaptations for continued survival

Interspecific competition

strategies to avoid competition

1. resource partitioning

2. temporal partitioning

3. developing specialized niches

• is differentiation of ecological niches, enabling similar species to coexist in a community

• ex: Anolis lizard species demonstrate this strategy

Resource partitioning

occurs when animals use the same resource but at different times (e.g one species feeds during the day while another feeds at night)

Temporal partitioning

give an example of developing specialized niches

ex: through natural selection, different species of honey creepers has evolved a specialized beak to take advantage of certain types of food resource

an interaction where one species kills and eats the other

predation

types of predation?

• carnivory

• herbivory

organism captures, kills, and consumes an animal

carnivory

consumption of plant material by an animal

herbivory

Where an organism (generally insect parasitoid) predates on another insects called host insect by laying eggs near or the host insects

Parasitoidism

• these eggs, hatched into larva that feeds on tissues of host insect and subsequently killed and eaten by the insect parasitoid

• has a life history intermediate between that of a predator and prey

• Consume nutrients and energy from host

Parasitoid

Parasitic activities are limited to?

Parasitic activities are limited to larval stage

Larvae consume the host either?

Larvae consume the host either partially or completely

Adult parasitoid are free-living and may be?

Adult parasitoid are free-living and may be predaceous

Parasitoid are confined to what orders?

Confined to orders Hymenoptera and Diptera

What are the kinds of herbivores?

1. Grazers/folivores

2. Browsers

3. Granivores

4. Frugivores

Consume leafy materials

Grazers/folivores

Eat mostly woody materials and bark

Browsers

Consume plant seeds

Granivores

Consume fruit

Frugivores

What are some feeding adaptations of predators?

Some feeding adaptations of predators are:

• claws

• Teeth

• Fangs

• Stingers

• Poison

• Search image

• Chemoreception

• Auditory sensation

What is the predator adaptation of whales?

echolocation

Prey adaptations include:?

• speed

• Crypticity

• Mimicry

• Camouflage

What is cryptic coloration?

• also known as camouflage

• Helps an organism blend into its surroundings

• Used to avoid detection by predators or prey

• Ex: canyon tree frog

Strategy used by organisms to avoid detection

Camouflage

• involves blending in with the environment

• Can include odor, patterns, shapes or behaviors

• Helps protect from predators or aids in hunting prey

Animals with effective chemical defense often exhibit bright warning coloration called?

• predators are particularly cautious in dealing with prey that display such coloration

Aposematic coloration

What is aposematic coloration?

• bright, conspicuous colors that signal danger or unpalatability

• Warns predators to stay away

• Often associated with toxins or defenses

• Ex: the bright colors of poison dart frogs

Imitation of a poisonous or dangerous species by a non-dangerous species

Mimicry

• a prey species may gain significant protection by mimicking the appearance of another species

A palatable or harmless species mimics an unpalatable or harmful model

• a harmless species mimics a harmful one

Batesian mimicry

Two unpalatable species mimics each other

Mullerian mimicry

• traits that help herbivores feed on plants effectively

Herbivore adaptations

Herbivore adaptation include?

• includes specialized teeth (broad, flat molars-back teeth) for grinding plant material

• Long digestive tracts to break down tough cellulose

• Behavioral adaptations like selective feeding

Have broad, flat molars (back teeth) with rough surfaces, which are used for grinding up tough plant tissues

Herbivores

Poisonous irritating or bad tasting compounds synthesized by plants as a defense

Plant adaptations to herbivores: secondary compounds

Plant adaptations to herbivores include?

• includes physical defenses (thorns, tough leaves)

• Includes chemical defenses (toxins, bitter compounds)

What are secondary compounds?

• poisonous, irritating or bad tasting compounds synthesized by plants as a defense

• Are chemicals not used for growth or reproduction

• Acts as detergents by making plants toxic, unpalatable or indigestible

• Help reduce herbivore and increase plant survival

• Ex: alkaloids in tobacco or tannins in oak leaves

Predator and prey species can?

Predator and prey species can drive each other’s evolution

• intense natural selection pressures between predator and prey populations

Describe cases where two (or more) species reciprocally affect each other’s evolution

Coevolution

The parasite derives nourishment from another organisms which is?

The parasite, derives nourishment from another organisms, its host, which is harmed in the process

Two kinds of parasitism?

Ectoparasites and Endoparasites

• live on the outside of the host’s body

• Feed on blood, skin, or body fluids

• Ex: ticks, lice, fleas

Ectoparasites

Songbirds are often heavily parasitized by?

• by ticks

• The birds are often anemic, stressed and more vulnerable to predation

• Female ticks must have a good blood meal in order to lay eggs

Often infect living organisms, such as plants, animals or other fungi

• fungal parasites

• This shelf fungus releases enzymes to digest the wood of this tree, which weakens the tree and makes it more vulnerable

• live inside the host’s body

• Inhabit organs or tissues (e.g intestines, blood)

Endoparasites

• ex: tapeworms, roundworms, viruses

Is a disease that is characterized by the thickening of the skin and underlying tissues, especially in the legs and genitals. Blockage of the lymph nodes

Roundworms: Elephantiasis

What are the evolution of parasites?

• Parasitism drives hosts to evolve defenses against parasites

  • parasites forced hosts (like humans) to develop defenses

• parasites evolve to efficiently exploit their hosts

  • parasites change and specialize to better survive inside hosts

Is an interaction which benefits both species

Mutualistic symbiosis

Where one species cannot survive without the other

Obligate mutualism

Where both species can survive alone

Facultative mutualism

What is plant mutualism

• plants form beneficial relationships with other organisms

• Ex: plants and pollinators. (bees get nectar, plants get pollinated)

• Ex: plants and mycorrhizal fungi ( fungi help absorb nutrients, plants provide sugars)

What is coral mutualism?

• corals form a mutualistic relationship with zooxanthellae (algae)

• Algae live in coral tissues and perform photosynthesis

• Algae provide oxygen and nutrients; corals offer protection and CO2

What are the types of mycorrhizal fungi?

1. Arbuscular Mycorrhizal Fungi (AMF)

2. Ectomycorrhizal Fungi

• the fungus grows into the soil, extending some distance away from the root

• Penetrates into some of the plant root cells

Arbuscular Mycorrhizal Fungi (AMF)

The fungus forms a mantle around roots and a netlike structure around root cells

Ectomycorrhizal Fungi

• one species benefits and the other is neither harmed nor helped

• Enhances fitness of one species; no effect on fitness of the other species

Commensalism

• an individual species harms another without obtaining benefit

• A nebulous relationship which involves chemical interactions such as allelopathy effect in plants and antibiosis

Ammensalism