3B1 Ecosystem Relationships

Question 1

What is an organism?

Answer 1

A single living entity.

Organisms include plants, animals, fungi, and microorganisms.

Question 2

Define:

Population

Answer 2

A group of individuals of the same species in a specific area.

Populations interact and reproduce within their environment.

Question 3

True or False:

A population can consist of different species.

Answer 3

False

A population consists of individuals of the same species.

Question 4

What is a community?

Answer 4

A group of interacting species in a specific area.

Communities are formed by various populations coexisting in a habitat.

Question 5

True or False:

A community includes only populations of the same species.

Answer 5

False

A community includes populations of different species.

Question 6

What is the relationship between populations and communities?

Answer 6

Populations make up communities.

A community consists of multiple populations of different species living and interacting in the same area.

Question 7

What are intraspecific relationships?

Answer 7

Interactions between individuals of the same species.

These relationships can be positive, negative, or neutral, affecting the survival and reproduction of the individuals involved.

Question 8

What is competition in intraspecific relationships?

Answer 8

It is when individuals of the same species compete for limited resources.

Resources such as food, shelter, and mates are often limited, leading to competition for their acquisition.

Question 9

True or False:

Intraspecific competition can lead to the elimination of weaker individuals.

Answer 9

True

Individuals that cannot access resources may not survive or reproduce, reducing their numbers.

Question 10

What is altruism?

Answer 10

When an individual helps another at a cost to itself.

This behavior is often seen in cooperative species where helping others improves the overall survival of the group or species.

Question 11

How does altruism benefit a species?

Answer 11

It can boost group survival and improve the chances of passing on genes.

Altruistic behaviors can increase the fitness of relatives, known as kin selection, or of the group as a whole.

Question 12

Fill in the blank:

Altruistic behavior often involves __________ to help others at the cost of an individual’s own resources or safety.

Answer 12

self-sacrifice

This self-sacrifice may increase the reproductive success of others in the group, particularly relatives.

Question 13

True or False:

Altruistic behavior can sometimes be directed toward non-relatives in some species.

Answer 13

True

In some cases, individuals may help non-relatives, which can indirectly increase the chances of their own survival or future reproductive success.

Question 14

What is territoriality?

Answer 14

The defense of a specific area against others of the same species.

This behavior is often related to securing resources like food, mating opportunities, or nesting sites.

Question 15

How does territoriality impact intraspecific interactions?

Answer 15

It reduces competition by granting exclusive access to resources.

Territorial behaviors can help individuals avoid costly conflicts over resources.

Question 16

Fill in the blank:

_________ is a behavior in which one individual helps another, sometimes at a cost to itself, in hopes that the favor will be returned.

Answer 16

Reciprocity

Reciprocity in intraspecific relationships is common in social species where individuals exchange favors.

Question 17

True or False:

Competition only occurs during times of resource scarcity.

Answer 17

False

Competition can occur anytime resources are limited or when individuals vie for mates or territory.

Question 18

What is the outcome of intense intraspecific competition?

Answer 18

It may lead to natural selection.

Intense competition drives evolutionary changes as individuals with advantageous traits are more likely to survive and reproduce.

Question 19

Define:

Interspecific relationships

Answer 19

Interactions between individuals of different species.

These relationships can affect the survival, reproduction, and distribution of species in an ecosystem.

Question 20

What is mutualism?

Answer 20

A relationship where both species benefit.

Both species provide something beneficial to each other, such as food or protection.

Question 21

How does mutualism benefit both species?

Answer 21

Both species gain resources or protection, enhancing survival.

An example is the relationship between bees and flowers: bees get nectar, and flowers get pollinated.

Question 22

True or False:

Mutualism can only occur between plants and animals.

Answer 22

False

Mutualism can occur between different types of organisms, including plants, animals, and microorganisms.

Question 23

Fill in the blank:

In parasitism, the ________ benefits at the expense of the host.

Answer 23

parasite

Parasitism is a harmful relationship for the host but beneficial for the parasite, which gains nutrition or shelter.

For example,* tapeworms* are a common parasite that live in the intenstines of mammals. It absorbs nutrients from the host’s food, depriving the host of those nutrients.

Question 24

What type of relationship involves one species benefiting while the other is unaffected?

Answer 24

Commensalism

An example is barnacles attaching to the skin of whales; the barnacles gain mobility and access to nutrient-rich water, while the whale is unaffected.

Question 25

How does commensalism **differ** from mutualism?

Answer 25

In commensalism, one species benefits, while in mutualism, both benefit. ## Footnote **Commensalism** doesn't provide any benefit or harm to the other species involved, unlike **mutualism** where both gain advantages.

Question 26

# True or False: In commensalism, the benefiting species **always** improves the survival of the other species.

Answer 26

False ## Footnote In commensalism, the other species is **neither** helped nor harmed, so there is no impact on its survival.

Question 27

What is **predation**?

Answer 27

A relationship where one species hunts and consumes another for food. ## Footnote This is common in ecosystems and plays a crucial role in regulating populations.

Question 28

# Fill in the blank: In predation, the \_\_\_\_\_\_\_\_ **benefits** from hunting and consuming the prey.

Answer 28

predator ## Footnote **Predators** are usually adapted to capture and kill prey, often with specialized hunting techniques or physical features.

Question 29

# True or False: Parasitism is **always** harmful to the host species.

Answer 29

True ## Footnote Parasitism harms the host by taking resources or causing disease, which can reduce the host's fitness.

Question 30

What does the term **coevolution** refer to?

Answer 30

The process by which two species **influence** each other's evolution. ## Footnote Coevolution often occurs in predator-prey and mutualistic relationships, where changes in one species lead to adaptations in the other.

Question 31

What is a predator's **role** in an ecosystem?

Answer 31

They **control prey populations**, maintaining ecosystem balance. ## Footnote By controlling prey numbers, predators prevent overpopulation and the depletion of resources.

Question 32

What is a **mutualistic** relationship between fungi and plants called?

Answer 32

Mycorrhizal symbiosis. ## Footnote Fungi *provide* plants with nutrients from the soil, and in return, plants supply fungi with sugars produced during photosynthesis.

Question 33

# True or False: Commensalism is **always** a permanent relationship.

Answer 33

False ## Footnote Commensal relationships can **change** over time, especially if environmental conditions change or if the relationship evolves into mutualism or parasitism.

Question 34

What is an **example** of mutualism?

Answer 34

Birds **eating** ticks off large mammals. ## Footnote The bird gains a food source (ticks), while the mammal benefits by having parasites removed, improving its health.

Question 35

How can parasitism **lead** to evolutionary changes in species?

Answer 35

Hosts **develop** defenses, while parasites improve exploitation. ## Footnote This ongoing *arms race* can drive adaptations in both the parasite and host species.

Question 36

# True or False: Two species can have the **same** niche in an ecosystem without competing.

Answer 36

False ## Footnote If two species occupy the same niche, they must *compete* for the same resources, which can lead to one species outcompeting the other.

Question 37

What is **resource availability** in an ecosystem?

Answer 37

The **availability of resources** like food, water, and shelter to species. ## Footnote Resource availability directly impacts population sizes, as species need these resources for survival and reproduction.

Question 38

What are limiting **factors** in an ecosystem?

Answer 38

Factors that **limit** population growth, like food, predation, and climate. ## Footnote Limiting factors *determine* the carrying capacity of an environment, meaning they control how many individuals the ecosystem can support.

Question 39

# Define: Carrying capacity

Answer 39

The **largest population** an environment can support. ## Footnote When a population exceeds its carrying capacity, resources become strained, leading to competition and a decrease in population size.

Question 40

# Fill in the blank: Critical population size is the \_\_\_\_\_\_\_\_ **number** of individuals required for a population to survive and reproduce successfully.

Answer 40

minimum ## Footnote Below this size, a population may face a high risk of **extinction** due to inbreeding, reduced genetic diversity, or other environmental factors.

Question 41

How does predation **impact** population sizes?

Answer 41

It **reduces** prey populations and helps maintain ecosystem balance. ## Footnote Predators regulate prey populations by removing individuals from the ecosystem, which can indirectly affect the growth of other species.

Question 42

What is **ecological succession**?

Answer 42

The **change in species structure** of an ecological community over time. ## Footnote Succession occurs in *stages*: primary succession starts in a barren environment, while secondary succession occurs after a disturbance in an existing community.

Question 43

# True or False: Ecological succession **always** results in the same stable community.

Answer 43

False ## Footnote Succession may lead to **different** stable communities depending on factors such as climate, soil, and species interactions.

Question 44

What is a **keystone** species?

Answer 44

A species that has a **disproportionately large** effect on its ecosystem. ## Footnote For example, *sea otters* control sea urchin populations, preventing overgrazing of kelp forests and preserving the marine ecosystem's balance.

Question 45

# Fill in the blank: Invasive species are \_\_\_\_\_\_\_\_ species that **harm** local ecosystems.

Answer 45

non-native ## Footnote Invasive species can **outcompete** native species, reducing biodiversity.

Question 46

How do invasive species **alter** ecosystems?

Answer 46

By **outcompeting** native species and altering environmental conditions. ## Footnote They can change food webs and displace native organisms.

Question 47

What causes ecosystem **disturbances**?

Answer 47

* Natural events * Human activities ## Footnote Both can **disrupt** habitats and species populations. Human activities can include pollution or deforestation, while natural events could include earthquakes or wildfires.

Question 48

What is the role of **pollinators** in ecosystems?

Answer 48

They **facilitate plant reproduction** by transferring pollen. ## Footnote Pollinators are essential for the reproduction of many crops and wild plants.

Question 49

# True or False: The **loss** of pollinators would have a massive effect on ecosystems.

Answer 49

True ## Footnote It would severely disrupt plant reproduction and the food web.

Question 50

# Fill in the blank \_\_\_\_\_\_\_\_ species are those that **naturally** occur in a specific habitat or environment.

Answer 50

Native ## Footnote **Native** species are adapted to the local environment and play important roles in maintaining ecosystem balance.