Ch.32 - Animal Diversity

Question 1

Ch.32 Goals

1. Defining characteristics of animals; describe general stages of embryonic dev.
2. Identify closest Protist ancestor, key fossil finds, and timing of major events
3. Recognize diff types of symmetry and groups incl
4. Interpret relationships depicted in phylogenies of animals

Answer 1

Ch.32 Goals

1. Defining characteristics of animals; describe general stages of embryonic dev.
2. Identify closest Protist ancestor, key fossil finds, and timing of major events
3. Recognize diff types of symmetry and groups incl
4. Interpret relationships depicted in phylogenies of animals

Question 2

What is an animal?

Answer 2

Eukaryotic

Multicellular; cells lack cell walls

Heterotrophic; obtain nutrients by ingestion

Have tissues that dev fr embryonic layers

• Tissues: groups of similar cells that act as a functional unit

Question 3

Animal cells lack cell walls. How are they held t/g?

Answer 3

Structural proteins

• Collagen - most common; only found in animals.

Question 4

Name two types of specialized cells

Answer 4

Muscle

Nerve

Question 5

T/F: animal reprod is exclusively sexual.

Answer 5

False

Some asexual reprod too

Question 6

What are the basic stages of embryonic dev?

Answer 6

Fertilization

Cleavage (mitotic div w/o cell growth) → Blastula

Gastrulation

Question 7

_______ are sexually immature and morphologically distinct from adult; specialized for eating and growth.

Answer 7

Larva are sexually immature and morphologically distinct from adult; specialized for eating and growth.

Question 8

Metamorphosis is the developmental transformation from larva to ______.

Answer 8

Metamorphosis is the developmental transformation from larva to juvenile.

Question 9

______ genes det morphology of organisms by laying out the location of the axis

Answer 9

Hox genes det morphology of organisms by laying out the location of the axis

• Found in ALL animals, but not in any other orgs
• Highly conserved, but prod wide variety of body plans.

Question 10

Estimated that animals split from fungi about ________ years ago

Answer 10

Estimated that animals split from fungi about 1 billion years ago

• Choanoflagellates: protists; closest to animals

Question 11

__________ are the closest protist relative to animals

Answer 11

Choanoflagellates are the closest protist relative to animals

Question 12

Early members of the Neoproterozoic Era (1 bil-542 mya) included _______ biota

Answer 12

Early members of the Neoproterozoic Era (1 bil-542 mya) included Ediacaran biota

Question 13

The Cambrian Explosion occurred ____ to ___ MYA, during the ________ Era.

Answer 13

The Cambrian Explosion occurred 542 to 251 MYA, during the Paleozoic Era.

• Marked earliest fossil appearance of many major groups of living animals.

Question 14

Most fossils fr Cambrian explosion are bilaterians, orgs w which traits?

Answer 14

Bilaterally symmetric form

Complete, one-way digestive tract

Question 15

Which era followed the paleozoic era, and featured the origin and diversification of dinosaurs?

Answer 15

Mesozoic (251 - 65.5 MYA)

Question 16

Diversification of mammals occurred in which era?

Answer 16

Cenozoic (0-65.5 MYA)

Question 17

Animal diversity continued to increase through the Paleozoic, but was punctuated by ___________

Answer 17

Animal diversity continued to increase through the Paleozoic, but was punctuated by mass extinctions

Question 18

Animals began to make an impact on land by ____ MYA.

Vertebrates made the transition to land around ____ MYA.

First mammals emerged during the ________ Era.

Answer 18

Animals began to make an impact on land by 450 MYA.

Vertebrates made the transition to land around 365MYA.

First mammals emerged during the Mesozoic Era (251–65.5 MYA).

Question 19

A ________ is a set of morphological and developmental traits

Answer 19

A body plan is a set of morphological and developmental traits

Question 20

Differentiate symmetry of body plans in sponges, cnidaria/ctenophora, and everything else.

Answer 20

Sponges (porifera): asymmetric

Cnidaria and Ctenophora: radial

Everything else: bilateral

Question 21

Describe radial symmetry

Answer 21

Top/bottom, but NOT L/R or front/back.

Typ sessile or planktonic (drifting or weakly swimming)

Question 22

Describe bilateral symmetry

Answer 22

Animal can only be divided by a single plane, running the length of the body

Question 23

Bilaterally symmetrical animals have:

Answer 23

Bilaterally symmetrical animals have:

• A dorsal (top) side and a ventral (bottom) side
• A R/L side
• Anterior (front) and posterior (back) ends

Many also have sensory equip, such as a brain, concentrated in anterior end

Often move actively and have a CNS

Question 24

__________ are a collection of specialized cells isolated from other tissues by membranous layers

Answer 24

True tissues are a collection of specialized cells isolated from other tissues by membranous layers

• Sponges and a few other groups lack tissues

Question 25

Tissues are the result of the _________ that occurs in development

Answer 25

Tissues are the result of the **gastrulation** that occurs in development

Question 26

\_\_\_\_\_\_\_\_ are diff layers created w/i the embryo

Answer 26

**Germ layers** are diff layers created w/i the embryo * **Ectoderm**: layer covering embryo’s surface * **Endoderm**: innermost layer, lines developing digestive tube (**archenteron**) * **Mesoderm**: b/w ecto/endoderm. * Only in triploblastic (bilateral) animals.

Question 27

Animals w *radial* symmetry are diploblastic, due to the presence of which two germ layers?

Answer 27

**Ectoderm**: layer covering embryo’s surface **Endoderm**: innermost layer, lines developing digestive tube (archenteron)

Question 28

Which germ layer is only present in triploblastic, bilateral animals? What is its fxn?

Answer 28

**Mesoderm**: b/w ectoderm and endoderm Forms muscles and other organs found b/w digestive tract and outer covering

Question 29

A _______ is a true body cavity, derived from mesoderm

Answer 29

A **coelom** true body cavity, derived from mesoderm * **Coelomates**: animals possessing a true coelom * Most *triploblastic* (bilateral) animals are coelomates

Question 30

Diff b/w a coelom and pseudocoelom

Answer 30

**Pseudocoelom**: body cavity derived from the mesoderm **and endoderm** * **Pseudocoelomates**: triploblastic (bilateral) animals that possess a pseudocoelom

Question 31

\_\_\_\_\_\_\_\_ are triploblastic animals that lack a body cavity

Answer 31

**Acoelomates** are triploblastic animals that lack a body cavity

Question 32

What is the purpose of the coelom/body cavity?

Answer 32

Fluid cushions organs Can act as a “skeleton” Separation from body’s surface

Question 33

Coelomates and pseudocoelomates refer to \_\_\_\_\_, NOT clades

Answer 33

Coelomates and pseudocoelomates refer to **GRADES**, NOT clades

Question 34

Coelomate animals can be divided into which two groups, based on events in their dev?

Answer 34

**Protostome** - spiral and determinate cleavage **Deuterostome** - radial and indeterminate cleavage

Question 35

Coelomate animals are divided into protostomes and deuterostomes based on which types of cleavage?

Answer 35

**Spiral vs radial**: * **Spiral**: daughter cells lie b/w pairs of cells above them. * **Radial**: cells aligned directly on top of ea/o. **In- vs Determinate**: * **Determinate**: fate of ea embryonic cell is set v early on. * **Indeterminate**: ea cell produced by early divisions retains capacity to dev into a complete embryo. •Stem cells, identical twins

Question 36

Summarize protostomes vs deuterostomes

Answer 36

**Protostomes**: solid masses of mesoderm split to form the coelom **Deuterostomes**: mesoderm buds from the wall of the archenteron to form the coelom

Question 37

A _______ is an indention fr wh the archenteron devs during gastrulation

Answer 37

A **blastopore** is an indention fr wh the archenteron devs during gastrulation Think: **D**euterostome & **A**nus, bc D & A closer in alphabet **P**rotostome & **M**outh, bc P & M closer in alphabet

Question 38

In protostome dev, the blastopore becomes the \_\_\_\_\_\_, while in deuterostome dev, the blastopore becomes the \_\_\_\_\_\_.

Answer 38

In protostome dev, the blastopore becomes the **mouth**, while in deuterostome dev, the blastopore becomes the **anus**.

Question 39

Common ancestor of all animals

Answer 39

Metaozoa clade

Question 40

What is meant by sponges being "basal animals"

Answer 40

First lineage to split off

Question 41

Animals w true tissues form which clade

Answer 41

**Eumetazoa** * Diploblasts are basal (first lineage to split off) fr this clade

Question 42

What are the three major clades of bilaterian animals?

Answer 42

Ecdysozoa Lophotrochozoa Deuterostomia

Question 43

Ecdysozoans shed their exoskeletons through a process called \_\_\_\_\_\_

Answer 43

Ecdysis (molting)

Question 44

Lophotrochozoa are defined by which structure?

Answer 44

**Lophophore** - feeding structure formed by a crown of ciliated tentacles around the mouth

Question 45

T/F: Ecdysozoans have some kind of exoskeleton or hard outer covering

Answer 45

TRUE Ecdysozoans have some kind of exoskeleton or hard outer covering

Question 46

\_\_\_\_\_\_\_ are basal to all animals

Answer 46

**SPONGES** are basal to all animals

Question 47

T/F: all deuterostomes have a pseudocoelom

Answer 47

TRUE all deuterostomes have a pseudocoelom

Question 48

T/F: sponges have no true tissue

Answer 48

TRUE sponges have no true tissue