Invertebrates: The Little Creatures That Run the World

These flashcards cover the essential concepts related to the importance, diversity, and ecological roles of invertebrates, including various phyla and current environmental issues affecting them.

What defines invertebrates?

Animals without a backbone.

What percentage of all described species of animals are invertebrates?

96%.

How many phyla are represented in invertebrate groups?

More than 35 phyla.

What is a positive characteristic that invertebrates do not share?

No single positive character in common.

Why are invertebrates important to study?

They are direct/indirect causes of many human, animal, and plant diseases.

Where do most invertebrates lie in food webs?

At or near the base of most food webs in all habitats.

What fields have invertebrates contributed to our understanding of?

Gene expression, cell division, aging, and more.

What is the primary structural characteristic of Phylum Porifera?

They have only cellular organization (Parazoa).

What shape are asconoid sponges?

Small and tube-shaped.

What structure do sponges use to create water currents?

Beating of flagella (choanocytes).

What are the reproductive methods of sponges?

Asexual reproduction by fragmentation or budding.

What are spicules made of in sponges?

Silicon or CaCO3.

Which cnidarians have a tissue level of organization?

Cnidaria.

What unique feature do cnidarians have?

Specialized stinging cells called cnidocytes.

What are the two body forms of Cnidarians?

Polyp and medusa.

How do jellyfish move?

They float in open sea with a thick mesoglea.

What type of cnidarians have nematocyst-bearing tentacles?

Feeding polyps (gastrozooids).

What is unique about Anthozoa?

They have no medusa stage.

What do corals rely on for photosynthesis?

Zooxanthellae.

What do coral reefs serve as a habitat for?

25% of all marine life.

Which areas are known as the Coral Triangle?

Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands, Timor-Leste.

What effects caused coral bleaching in 1998?

The El Niño/La Niña climate pattern.

What disturbances threaten coral reefs?

Disease, sedimentation, pollutants, and climate change.

What happens during ocean acidification?

Increased CO₂ lowers the pH and affects coral growth.

What impact does a lower pH have on coral?

It blocks growth and can lead to dead coral.

What is the Great Barrier Reef known for?

Being the world's biggest single structure made by living organisms.

What is the economic value of the Great Barrier Reef?

$56 billion.

How much of the Great Barrier Reef has bleached since 2016?

Half of the reef.

What are ctenophores commonly known as?

Comb jellies.

How do ctenophores capture their prey?

Using long tentacles with colloblasts.

What kind of gut do ctenophores possess?

A complete gut with mouth and two anal pores.

What type of reproduction do comb jellies undergo?

They are hermaphroditic.

What is unique about the muscle arrangement in sea anemones?

They have both circular and longitudinal muscles.

What role do zooxanthellae play for corals?

They assist in photosynthesis and nutrient supply.

What is the consequence of crown-of-thorns sea stars on coral reefs?

They can contribute to coral bleaching.

What defines the dominant structure of sponges?

Saclike bodies perforated by many pores (ostia).

How is the water expelled from a sponge?

Through the osculum.

What features identify hydrozoans?

Colonies of polyps with hard, chitinous coverings.

What is the primary issue faced by coral reefs according to recent studies?

Climate change leading to increased temperatures and ocean acidification.

What is the relationship between ocean acidity and coral growth?

Increased acidity leads to weaker corals.