Questions and Answers
Animals are an amazingly ___________ group of organisms.
Diverse
Animals share certain characteristics, which are features that can be _________.
Inherited
Unlike plant cells, animal cells do not have ______.
Cell walls
Also unlike plant cells, animals cells cannot make their own food. They do not have _________ for photosynthesis.
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All animals are _______, meaning they must eat their organisms to get the nutrients they need.
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All animals are ________. All animals are _____.
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A vertebrate is an animal with an internal, segmented _______.
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Humans are ________.
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Most animals we think of are vertebrates, but vertebrates make up less than _____% of all known species.
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Most animals are ________. They have no backbones.
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Because of their body plan, ______ may be the most primitive animals on Earth.
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Sponges have no _____ or ______.
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They are _____, meaning they cannot move.
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Sponges do not have mouths. They are ______. This means they strain food particles from the water.
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Cnidarians move using simple ____ and muscles.
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A common example of a cnidarian:
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Flatworms do not have _____ or lungs.
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They are flat and thin because they have no _______ system.
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______ are diverse animals. They include very different animals such as oysters and squids.
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Some annelids are referred to as ______ worms.
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Segmentation refers to the repeated _____ of an annelid's long body.
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Roundworms are found in almost every _____ on Earth.
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These worms are not only one of the most numerous species on earth, but they also have the most diversity among species. Many roundworms are ______.
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A _______ lives in the digestive tract of its host, where it feeds on the host's blood.
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A _______ lives in the gut of its host. Infections usually occur when a person eats or drinks something that contains its eggs.
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________ and sea urchins are two common echinoderms.
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Arthropods are the most ______ animal phyla on earth.
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Arthropods are ______ with an exoskeleton made of chitin.
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How do arthropods move? Very stiff cuticle plants are separated by more flexible ones. The flexible cuticle plates act as ____ so the animal can move.
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_______ (or growth): the shell cannot grow. An arthropod must shed its exoskeleton in a process called ________.
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Some arthropods are _________ vectors. They spread human diseases.
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______ (1347-1350) killed millions of people living in Europe. It is caused by a bacterium carried by a _________.
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Study Notes
Animal Diversity and Characteristics
- Animals are a diverse group of organisms with various characteristics that can be inherited.
- This diversity suggests all animals share a common ancestor dating back millions of years.
- Animals differ from multicellular organisms, notably through features like the lack of cell walls in animal cells.
Nutrition and Cell Structure
- Animal cells lack chloroplasts, necessitating dependence on other organisms for nutrition.
- All animals are heterotrophs, meaning they obtain nutrients by consuming other organisms.
- Animals are categorized as eukaryotes and are predominantly multicellular.
Vertebrates vs. Invertebrates
- Vertebrates possess an internal, segmented backbone; humans are classified as vertebrates.
- Vertebrates constitute less than 5% of all known animal species, while the vast majority are invertebrates, which lack backbones.
Primitive Animals: Sponges
- Sponges are among the most primitive animals, with fossils over 570 million years old.
- They are unique in that they lack muscles and nerve cells and are sessile (non-moving).
- As filter feeders, sponges extract food particles from water without mouths.
Cnidarians and Other Invertebrates
- Cnidarians, such as jellyfish, possess simple nerve systems for movement.
- Flatworms do not have stomachs or lungs and are thin due to the absence of a circulatory system.
- Mollusks include a variety of forms like oysters and squids, exhibiting diverse dietary roles.
Annelids and Roundworms
- Annelids, including earthworms and leeches, are segmented, characterized by repeated sections in their bodies.
- Roundworms thrive in nearly every ecosystem and show significant diversity; many are parasitic.
- Examples of parasitic roundworms include hookworms and pinworms, which infect hosts through contaminated soil or food.
Echinoderms and Arthropods
- Echinoderms such as sea stars and sea urchins possess internal skeletons made of tiny plates.
- Arthropods represent the most successful animal phylum, making up over three-quarters of known animal species.
- They are invertebrates with chitin exoskeletons, paired jointed appendages, and segmented bodies.
Movement and Growth in Arthropods
- Arthropods have a stiff cuticle with flexible joints that facilitate movement.
- Molting is the process by which arthropods shed their exoskeletons to accommodate growth.
Human Health Impact
- Some arthropods act as disease vectors, spreading illnesses such as the bubonic plague, which is caused by a bacterium delivered through fleas.
- The bubonic plague historically decimated populations in Europe from 1347-1350.
Overall Significance
- Understanding animal diversity and their categories is crucial for grasping biological concepts and their applications in health and ecology.
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Test your knowledge on key concepts from Biology Unit 14 with these flashcards. Each card addresses essential terms and definitions related to animal characteristics and cell structures. Perfect for review and preparation for exams.
